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Energy/Electricity Storage and Use/Grid Connection => Off-Grid, Batteries & Inverters => Topic started by: book_woorm on November 05, 2015, 10:51:51 AM



Title: UPS and Growatt SP2000 unit
Post by: book_woorm on November 05, 2015, 10:51:51 AM
Anybody tried connecting a the 48v LIFEPO4 battery of a Growatt SP2000 to a UPS yet? Ok you would need to take out the old SLA's and disable the charging circuit in the UPS and the UPS would need to be a 48v one. This strikes me as a relitavely cheap way of getting both self consumption and a backup supply for things like solar thermal controllers and borehole pumps.


Title: Re: UPS and Growatt SP2000 unit
Post by: roys on November 05, 2015, 11:14:38 AM
Oh interesting, I have a 48V UPS waiting for a use.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 05, 2015, 11:29:46 AM
What make and model number is the UPS have you got? I haven't sourced one yet I need something like 4 amp to drive the single phase/capacitor run pump plus 200 watts or so for solar thermal/heating controls/fridges etc.


Title: Re: UPS and Growatt SP2000 unit
Post by: roys on November 05, 2015, 11:51:04 AM
It is a Compaq R3000h so it has about a 2800 VA output.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 06, 2015, 09:31:59 AM
Hi all,

I am currently running some tests on my own build.

I have got 2 ups systems,
1. A 6 kva socomec sicom 48v battery set up
2. A 10kva apc smart 10000xli a 200v DC battery set up.
my first tests will concentrate on the smaller ups, a socomec sicom 6kva. This has a 48v sealed lead acid battery.

I also have 2 sets of lithium batteries,

Set 1 is a Nissan Leaf set of 14 modules, these are lithium cobalt manganese chemistry, are in 2 sets of 7 modules to make either a 7.5 kWh 48v system for the socomec sicom ups, or as 96v battery as a half battery for the 10kva ups. I'd need another 14 Nissan Leaf modules to complete the battery, I'd imaging I'd get these quite soon.

Set 2 is a lifepo4 battery 48v 165ah system giving 8 kWh energy storage, I've been using this battery in a Toyota Prius plug in hybrid conversion for 18 months with no issues, only removed to fit a leaf battery with 16kwh for more range.

I have already run the ups from the leaf battery, and it is still set up and working, and it works very well.
Charging is done by a 48v 1kw meanwell power supply, these are reliable units and reasonably cheap for what they are. They can be adjusted from 44v to 58v so can be adjusted to match the battery full capacity setting with alittle time. For instance, the leaf modules can be charged to 4.2v max, I take them to 4.1v max and the charger is set to 57v and works well. The charger is switched off using a cell log device that has an alarm switch that can be set to whatever cell voltage you choose within the parameters of the cell chemistry. I have had this type of set up working on the Prius plug in conversion with no issues, and still use the same set up with the leaf batteries in the Prius too, which I am still using today.

So, it can be done, as I am currently setting up a similar system using my own equipment, it has gone through 5 full cycles only with no problems. The ups reports no power left as it still thinks the original battery is fitted, but in practice it keeps running until it's switched off and the battery is recharged. When the ups is then switcjphed back on with a full battery it reads full.

These home energy solutions are really great and the lithium chemistry is very very good, with current prices though I feel they are too expensive.

Anthony.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 06, 2015, 10:18:35 AM
How did you turn off the battery charging system in the ups? I've not been able to find service manuals for these things, the manufacturers seem to keep this information under wraps.

I'm looking for an automatic change over from grid to standby to keep a number of critical systems alive and the standard switch over in a UPS will do what I want but I need to disable the battery charging. I'm intending putting those critical systems on their own distribution unit down stream of the UPS. I'm also thinking of taking the Growatt SP2000 230v supply from the critical systems distribution unit and putting the output of the solar inverter back into the same panel. On mains failure I can then let the inverter sync to the UPS and keep taking power from the sun and lighten the load on the battery.


Title: Re: UPS and Growatt SP2000 unit
Post by: biff on November 06, 2015, 03:20:04 PM

(http://s4.postimg.org/dc9z3c67t/DSCF0334.jpg) (http://postimg.org/image/dc9z3c67t/)

(http://s13.postimg.org/eiyoepi0j/DSCF0331.jpg) (http://postimg.org/image/eiyoepi0j/),
       Would these not be a bit heavy for the Prius, ?
                                           Biff


Title: Re: UPS and Growatt SP2000 unit
Post by: roys on November 06, 2015, 04:49:03 PM
Biff take it these are your old lead acids, pity the scrap price is at a low just now.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 06, 2015, 06:00:39 PM
Nice one biff, I thinks the suspension legs instead of being vertical would be horizontal with those in the boot.....

Hi book worm,

The tests I've been doing are with the socomec sicom ups.
This ups has a separate battery box and its own charger built into the box, so, what I did was purely remove the original batteries from the box (4 rows of 12v lead acid) and connected up my leaf battery. The ups is never powered on at the same time as the my own separate meanwell power supply charger so the charge circuit of the ups is never operational.
In fact as I can cold start the ups without AC power connected to it, there is no need for AC power at all with it. This way there's no need to consider the ups battery charge circuit as it won't have an AC supply for it to operate, at least in my set up. Not sure if that makes sense to you.
I can contro the meanwell power supply with voltage cut off relays or cell alarm relays. Won't power on again until I press a start switch.
Ask away if you'd like more info.

Thanks.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 06, 2015, 06:11:50 PM
Just noticed too those grow at units are over 3000 plus vat for 4kwh of lifepo4 storage, wow. I didn't pay that for a 24kwh Nissan Leaf pack.
I was considering selling my 8kwh lifepo4 pack as it's different chemistry to the leaf pack and integrating them together won't be easy.

I have had another leaf pack that I sold on with alittle profit to help me with my project, may be getting another one soon.
Anthony.


Title: Re: UPS and Growatt SP2000 unit
Post by: biff on November 06, 2015, 06:35:25 PM

(http://s15.postimg.org/l4hi1dfk7/DSCF0335.jpg) (http://postimg.org/image/l4hi1dfk7/).
   Yes roys,
        Scrap lead is a bit low in price is right but that can change overnight, and then I will send these on. :crossed
                                           Biff


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 12, 2015, 04:37:29 PM
Has anybody come across this piece of kit?  http://www.ebay.co.uk/itm/221919476559?euid=d2d8047dafbb4236967361f06324c49d&cp=1.

I'm told its made by Victron! and you can turn the charging circuit off.

It looks as though I might be easier to use than hacking an APC UPS to work with LiFEPO4 batteries. I would prefer not going down 'glyndwr1998's' route of manually switching over. By the way where do you get Nissan Leaf batteries from? The people I've asked down here in the South West all say the batteries have to back to Nissan when a car is written off.

I'm also looking at alternative sources of Growatt SP2000 unit. You can get them without the battery for 1000 is the best I've found so far Then you can have a battery as big as you can afford.





Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 12, 2015, 07:20:45 PM
Hi bookworm,

Funny enough I have been looking at those low frequency inverters too, but the 5kva model. They are polish. I have tried find out out info on them from other forums but very little that I can understand.

I have obtained the Nissan Leaf packs from a salvaypge yard, from an accident damaged leafs. I have got a few contacts now set up so they have the opportunity to contact me when one comes in.
The batteries in the leaf are owned not rented, so they are part of the car and can be sold to anyone who has an interest in buying one.
The Renault Zoe, fluency and twizy are battery rentals, in those cases the company responsible for the rental agreement arrange the recovery of the battery and it is sent back to Renault.
The battery in the Peugeot ion, Citroen czero and Mitsubishi are all also owned, so the salvage yards are free to sell them on too.

Honestly, the hack to the ups isn't great or technical, all old school stuff like temperature controllers with relay outputs to control temp, voltage meter with relay output to control pack overall voltage and cell log devices to have individual cell monitoring with relay output to alarm if cells go out of tolerance.
The charger is also set up to deliver slightly less than pack absolute high voltage so in the event of all other controls failing, the charger will never deliver more than what the battery can take, once the battery voltage reaches the charger output voltage no current flows.

Of course a bms could be purchased and installed at vast expenxpsive for peace of mind, but I have chosen to stay with old school stuff and relays rather than a heap of electronics and balance circuits.

I haven't finished my battery back up yet, waiting for the voltage meters. I've got the temp controller, cell loggers, DC circuit breakers etc... As soon as the voltage reg turns up I'll finish the set up, run some tests, then post pics and blog of how it works for anyone who's interested.

If you would like any info, ask away, I'll help if I can.

Anthony.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 13, 2015, 10:28:34 AM
Hi, I've managed to get this from the people who are selling the polish inverters https://www.dropbox.com/s/j983gegjmpti9o0/Manual%20E%20and%20W%20eng.pdf?dl=0

The other thought I had if I cant find out how to turn off the charging circuit in the ups was to put a diode between the LiFePO4 battery and the ups. It would be large and throw away a lot of heat but it would protect the battery from the SLA charger. 


Title: Re: UPS and Growatt SP2000 unit
Post by: roys on November 13, 2015, 02:56:29 PM

I haven't finished my battery back up yet, waiting for the voltage meters. I've got the temp controller, cell loggers, DC circuit breakers etc... As soon as the voltage reg turns up I'll finish the set up, run some tests, then post pics and blog of how it works for anyone who's interested.

If you would like any info, ask away, I'll help if I can.

Anthony.

I would certainly be interested in reading about the in and outs of this project, good luck with it.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 13, 2015, 04:42:11 PM
Turns out the Volt units are not compatible with LiFePO4!!! Just have to keep searching.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 13, 2015, 05:33:10 PM
This is the issue I found.

Trouble is the off grid stuff is designed for lead acid and with lithium batteries new to market there's not a lot about for reasonable money.

Also, there's a lot of bad press regarding lithium cells and their volatile nature. I am no battery expert but did read a great deal on lithium battery technology before I took the plunge and convert my standard Prius to a plug in Prius using lithium batteries. There are a few different lithium technologies available of which 2 are mainstream in the ev market.

Limnco2, or lithium cobalt manganese, all ev manufacturers use this tech, high energy density
Lifepo4 lithium ferrous phosphate, Chinese designed, a lot of use in the phev and ev conversions, not much Oem ev usage

Lipo or lithium polymer, very high energy density, not used at all in the ev industry hobby remote control stuff. Very unstable out of its operating parameters.

Most self converted electric vehicles use lifepo4 as they were cheaper to purchase, but as crashed Nissan leafs become available, most ev converts I know through various forums would opt for the leaf packs as they will be cheaper.
I have been using lifepo4 for about 2 years, had no issues with them at all, very stable, don't go out of balance, easy to charge, no profile, just charge to max voltage or your desired max voltage per cell. In my case that would be charge to 3.5 v and discharge to 2.8v, well within the manufacture tolerance of 3.8v and 2.5v.
For this project I will be using a current limiting meanwell 750watt 48 v power supply as a charger,


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 14, 2015, 09:47:10 AM
Hi, glyndwr1998 - I to have researched the chemistries available. Having seen the sort of ventilation that the GPO used to have for its battery banks and the consequences of a ship fire started by SLA's that weren't sealed! coupled with my neighbours horror stories of lithium ion on aeroplanes (he was an air accident investigator) I'm going to go for LiFePO4. I just hope the prices start to come down.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 14, 2015, 11:14:14 AM
Lifepo4 is a good choice, I have been using them for 2 years with no issues.

How many kWh capacity are you looking for, I am on a few ev forums where members sometimes sell on their old packs for upgrades in range.
Most of the horror stories surround the lipo chemistry.

The leaf cells too are very good.

Anthony.


Hi, glyndwr1998 - I to have researched the chemistries available. Having seen the sort of ventilation that the GPO used to have for its battery banks and the consequences of a ship fire started by SLA's that weren't sealed! coupled with my neighbours horror stories of lithium ion on aeroplanes (he was an air accident investigator) I'm going to go for LiFePO4. I just hope the prices start to come down.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 15, 2015, 12:27:49 PM
I'm contemplating adding some more panels at the same time as I get battery kit - But being in a National park I need planning permission to modify the roof so that I can put panels where the dormers won't shade them, then there's the wood work as well. A job for the spring I think.

As a mater of interest what can you get a 'Leaf battery' for? and what are its dimensions, the scrap yards around here are not being very helpful. I like the idea of a big battery something around 22KwHrs I believe.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 15, 2015, 02:12:47 PM
Hi bookworm,

A Nissan Leaf complete battery is quoted as being 24kwh, with about 22kwh useable.
The pack is split into 3 modules,
Module 1 is 24 cells in a block, 196v max voltage,
Modules 2 and 3 are 12 cells in a block and 98v each.

They can easily be reconfigured using the existing battery buss links.

The apc 10kva ups I have has an input for an external 200v DC battery so maybe module 1 can fit with this type of ups fairly easily.

For a 48v ups system you'd need only 7 cells in series, this is how I have my leaf module configured. 7 cells is about 3,5 kWh and I have 2 in parallel making 14 cells at roughly 7 kWh with a couple of spares.mwith the voltage parameters I want to run to the working capacity would be more to 6 kWh so shorten the depth of discharge and extend battery lifespan.

A complete leaf battery at 24 kWh would fetch 3000 quite easily, and would not hang around long at that price either.

Lifepo4 currently sells for about 1 per ah plus vat in the UK.

I have recently sold a leaf battery complete for similar and could have sold it 5 times over at that.
In a complete state they fill the whole floor pan of a leaf, YouTube shows a good video of a leaf battery tear down that'll give you an idea of individual cell size and whole pack size.

Anthony.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 16, 2015, 04:35:49 PM
I'm curious; What is your thinking to use 7 cells for each nominal 48V battery made up from 'leaf' cells, that comes out at 57.1666v? Ok so there are few cells left over once you've made up 6 lots of 7 cell batteries so you can eliminate any that aren't too hot. Am I right in thinking each leaf cell is actually 4 pouches in 2x2 series-parallel or is it parallel-series?

I know the chemistry of LiMnCo2 is different again, but at what voltage are you going to turn the charger off on the charge part of the cycle and at what discharge voltage are you going to shut down the inverter to prevent over discharge?


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 16, 2015, 07:38:01 PM
Well, I looked on the ev forums at the charge cycle for their 48v lead acid packs and they seem to be charged to 57.5v, of course they will drop back alittle from that setting.

I've set the power supply to 57v, that equates to about 4.1v per cell, the leaf cells are 2 in parallel 2 in series, so one built cell would then be 8.2v, the charger at 57v is alittle less than this.
The cells can go to 8.4v max voltage.

The cut off voltage will be set to 50.5v, that equates to around 3.6v per cell, or 7.2v per built up leaf cell. The lowest r commended voltage for these is 2.5v,or 5v per built up cell, so well within lowest range to save the battery life. Also, the discharge curve drops quite rapidly after 3.5v.

I figured the ups must be ok operating at 57v as that what it is set to charge to, I'm no expert, so I ran a few cycles at these settings and everything worked ok. Had a 6kwh actual capacity with this working voltage range.

So, charge max set point will be 57v

Max discharge set point 50.5v.

I have got hold of a few Peter Perkins type bms slave boards, and a master, that could be used to run and contro the pack, the settings on the slave and master picaxe chips would need to be reprogrammed to work with the leaf cells, but they are in the voltage range so could and should work ok, I haven't any programming experience at all, so it's a massive learning curve for me personally with the bms system, but I do have one full system here that could be used, it's just I'd need to learn how to use it, and to diagnose it if things started to go wrong with it.

At least with the system I will be using its old school voltage, temp and current sensing via relays, I can cope with this ok.

I wish I had someone local who was a hobbyist like me who knew how to program and could show me some basic commands just to get me to learn only what I need to, ie, program voltage and temp parameters in c+ or arduino.
I have 2 complete 16 cell slave boards enough for 2 48 v systems, and 1 master unit, an arduino or duinomite can be used for the second system if I knew what I was doing.

Anthony.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 16, 2015, 07:56:32 PM
Also, there is a chap on a German photovoltaic forum from Norway that uses I think 2 complete leaf packs in a 7 in series configuration working with a sunny island and that works very well, so I figured if he's using 7 in series successfully then I'll try it too.


Title: Re: UPS and Growatt SP2000 unit
Post by: roys on November 16, 2015, 08:41:54 PM
Hi glyndwr1998 where about in the world are you roughly speaking, as this sounds an interesting project.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 16, 2015, 09:18:31 PM
Hi Roy's,

South Wales valleys buddy, a small town called Aberdare.

Most of my parts came today, so I can start wiring up the 12v control circuit tomorrow, I'm still waiting on a 12v power supply for the supply to the relays, but I can use a battery for testing purposes.

I'm going to,use a programmable voltmeter with current shunt to measure the pack voltage and current, this has the facility to switch a relay on max and min voltage, current overload too. And visually provides an instant voltage and current delivery form the pack at any time.

I've got 2 programmable temperature controllers that have a relay swtich output to keep an eye on the battery packs

2 junsi celllog 8m devices will keep an eye on individual cell voltages and these can be programmed in various ways, ie, cell max and min settings, pack max and min settings, cell variance between cells, cheap but effective.

I'm hoping to start the wiring of the control circuit tomorrow.

Hi glyndwr1998 where about in the world are you roughly speaking, as this sounds an interesting project.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 17, 2015, 09:51:03 AM
Can you reprogramme the top voltage on the Celllog it appears to only goes up to 43V or are you going to use one over 4 cells and the other over 3 of the pack. Might not work though as I think the cells need to be in serial pairs which would might snooker use on your 7 cell pack even if you can reset the top voltage.

As I'm after something very similar myself 'd like to help, but I'm 150 miles away via the Severn bridge on Dartmoor. I've done quite a bit of Arduino programming in the last few years and I learnt to program many years ago on a LEOII (machine code, 5 hole punched tape etc.). I've found the thing that takes the most time is physically designing and setting up the sensor interfaces to the chip. Lots of issues there of electrical and mechanical security not to mention safety. The software is not too much (for me anyway) provided you don't run out of space on the chip, then you have to start dismantling the code of the libraries to make custom versions that save space. I'm having to do that on the second generation of my differential thermal controller to get the extra functionality in (more channels, better web interface, better download of data log files etc )



Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 17, 2015, 10:14:16 AM
Hi bookworm,

I have been using the cell loggers for over 2 years in the Prius conversion and they work very well.
The have an 8 cell input, so can read any cells up to 8, so 1 cell logger does 7 cells ok, I already have these fitted and working ok for my cycle test runs on the ups.

I'm going to start on the wiring later, and when I'm finished I'll do a video walk through and put it on YouTube, please bear in mind I'm no expert, so the experts out there will probably pick a lot of holes in what I'm doing, so, I'll listen to that advice and maybe revise to revision 2 after the experts cast their eyes over what I am doing.
I think I'll be ok though, got most things covered, I have got something similar already running in the Prius at 265VDC, and just basically copying the control circuit plus additional temp controllers.
There is a small electronic circuit via a breadboard, basically the cell loggers output via a transistor that is very sensitive or weak, so I take that output and onto a breadboard, through a resistor and connect to an opto isolator, this protects the Vella logger and provides total isolation to other circuits.
All wil become clear in the photos and video.

The Peter Perkins BMS was developed over on the battery vehicle society forum and has proven to be very successful and reliable.
I have the 16 cell slave boards, and version 2 master, basically the save boards have a pic 12f683 to each cell to read cell temp and voltage on a slave bus, the data is transmitted from the slaves onto the master bus and passed to the master pcb, this then extrapolates the cell info, has cell parameters set up and balancing circuits to balance the cells at the top end, balance resistors open at 3.6v, max charger cut off 3.8v. These levels are too high for me for lifepo4, I'd rather open the balance at 3.45v and max cell voltage 3.55v.
From running the lifepo4 in the Prius for over a year, the voltage climbs very quickly past around 3.48v.
All this was see signed before the arduino and similar micro controllers became available.
The las
a newer version has been designed on the forum by a chap called Greg fordyse, using a ltm 14 cell chip designed for battery management, his later type also works very well, it is open source, I cell board doing 14 cells costs about 60 in parts, and the controller he used was a duinomite, the later models of this type of platform from olimex use very fast dual and quad core cpu tech like in mobile phones, and can be used as master controllers to comms to slave ic,s via a I2C protocol, which is sadly out of my depth at the moment.
I'm a time served mech eng 50 yrs old, got a degree in mech eng, ok At electrics, and am very keen to learn to program, I'm sure if I sat down with an expert for a day, I'd get the basics enough to get by and learn along the way.
I have got Plc experience via my manufacturing experience and have sat a 2 day Plc course to program and fault find on Plc circuits, so it's not alien to me, and I can learn very quickly, but am much better being shown and examples rather than reading on my own.

I am learning every day on this project and really enjoyed converting the Prius too to a plug in hybrid using 16kwh of Nissan Leaf cells.

Anthony.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 17, 2015, 01:10:03 PM
The Peter Perkins bms is open source, I have the latest revision of the code in txt and hex format, the same for the master pcb.
With the advancement in technology over the last few years, very powerful micro controllers now exist for little money, a olimexino pcb that has many I/o pins, hdmi out, 4gb on board ram, supports uart has Ethernet, and much much more is around 40 euros, it can operate well as a master controller communicating to a slave via a twisted pair of cables on I2C platform, code is easy (apparently) if you know what your doing, and are very stable.
I just wish I knew how to use them. If they were Plc ladde based based I'd be ok.


I've found the thing that takes the most time is physically designing and setting up the sensor interfaces to the chip. Lots of issues there of electrical and mechanical security not to mention safety. The software is not too much (for me anyway) provided you don't run out of space on the chip, then you have to start dismantling the code of the libraries to make custom versions that save space. I'm having to do that on the second generation of my differential thermal controller to get the extra functionality in (more channels, better web interface, better download of data log files etc )




Title: Re: UPS and Growatt SP2000 unit
Post by: roys on November 17, 2015, 04:09:59 PM
Hi Anthony, pity you are so far away, I am up in Scotland.  I will be following this project with interest though.
PS I have a 300mA selectable voltage up to 12V wall wart transformer if you need it?


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 17, 2015, 05:21:45 PM
Hi bookworm,

Re the cell logger devices, I am sorry I made a slight error in my description,

To clear things up, I have 7 leaf cells and as they are parallel and series makes actually 14 cells, and 2 cell loggers monitor the 14 cells per pack, so in total for me I have 4 cell loggers in total, 2 on one pack and 2 on the other, if that makes sense. On each pack cell logger 1 has all 8 cells monitored, cell logger 2 monitors the remaining 6 cells making all 14 cells covered.
Same on pack 2.
Sorry for the confusion.

Made a start today, bought a wooden base to mount the equipment on, and planned the cable run and equipment positions. A few other things cropped up with th wfamily to had to down tools. Won't have time tomorrow to do anything at al so back to it on Thursday now.

Hi Roy's, thanks for the kind offer of the power supply, I think I have everything I need now, I have ordered a meanwell power supply for the relays, that'll be here soon. Thanks for the offer anyway, much appreciated.

Thanks to all your interest with this, it's a damn shame the Oem stuff is really expensive, wouldn't have to mess around with all this otherwise. I havent really noticed the lifepo4 prices come down in price either lately, a 24kwh pack in lifepo4 at current prices would cost nigh on 6000 plus vat. Ouch.....



Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 18, 2015, 09:44:46 AM
Indra had some Synopoly 100AHr LiFePO4 cells on fleabay the other day for 105 each so I think even your 6K is a bit shy.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 18, 2015, 12:26:36 PM
Indra had some Synopoly 100AHr LiFePO4 cells on fleabay the other day for 105 each so I think even your 6K is a bit shy.

Agreed, it was a very conservative estimate, and indra are the cheapest oitlet I have seen for lifepo4, prob another 20% at least on top of that plus the vat on top of that, with that a leaf pack at 3k is very very good value that is if you could get hold of one.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 20, 2015, 10:21:29 AM
Hi Antony, Just a thought in the set up your putting together which side of your battery are you connecting to earth or are you expecting the UPS to do that for you? From the circuit diagrams I've seen in a conventional UPS with its proprietary batteries & battery boxes the earth is both in the inverter and in the battery box.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 20, 2015, 04:26:03 PM
Excellent question, hadn't really considered the earthing.. Oops.

The additional battery box that came with the socomec ups had no additional points of connection for earth or anything else, so I'd assume the earthing is acheived through the ups, and all I have done is disconnect the original battery connections x 4 and connect my batteries to the original connections, ensuring the protection of the original battery circuit could be utilised.
Any suggestions, I'd rather be super sure and safe than wing it.

Thanks very much for the help.

As a progress, I've now completed the wiring off the battery to the battery box via the current shunt and DC circuit breakers, tested the voltage / current programmable meter, all is working ok, on a  2 kW load on the ups the voltage was showing 55.6v and the current was 39 amps, checked with my multimeter and DC clamp meter, readings were nigh on the same, so very pleased with that.
I'll continue with the 12v control circuit over the weekend, it won't take long to do its just getting the time to get into the shed, family pecking away at my time at the moment.....

Anthony.

Hi Antony, Just a thought in the set up your putting together which side of your battery are you connecting to earth or are you expecting the UPS to do that for you? From the circuit diagrams I've seen in a conventional UPS with its proprietary batteries & battery boxes the earth is both in the inverter and in the battery box.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 20, 2015, 07:58:51 PM
Hi Antony,
       So step one is successful. Doing the quick sum Output/DC volts x Amps your getting a 92% efficiency from the UPS I would have thought it should be a bit better than that. You are throwing away 168 watts some where. I presume that you are using an electric heater as the load for testing. Can you measure the AC Amps & volts at the same time? If its a fan heater the motor driving the fan will have a reactive component giving a power factor of less than one which will knock the efficiency back. Use a pure resistive load if you can in the first instance.
       When my mate tested his water wheel system a few decades ago we rounded up all the electric fires in the village as a test load and were surprised to discover how inductive all those old coiled electric heater filaments in there ceramic holders actually were! If you've ever done professional load testing on generators of 100's KVA upwards you will have heard that the load banks that you can hire from the likes of 'TestBank' have specially wound non-inductive resistors to make up the load.
       If you are going to run motors in fridges heating systems etc you will also need to do your tests with those inductive loads, VA is not watts as you know anyway. Florecent lights have a leading PF and switching power supplies throw god knows what up in the way of harmonics. If your interested there is a method shown in my Fowlers pocket book that lets you work out the phase angle/power but it needs 3 volt meters and known non inductive high power resistor in series with the load. 


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 20, 2015, 08:21:39 PM
Hi bookworm,

The load was a 2kw fan heater, I'll try to ripen a test on it tomorrow to see what it is actually consuming when powered up.

To be honest and probably being abit naive, and being mechanically biased not electrically, I haven't considered the effects of different equipment on the pf or harmonics. I did intend using a switch mode power supply to run the 12v supply for the 12v cut off relays and control circuit. Does that have a bad detrimental effect of the condition of the supply?
I'm open to any suggestions you may have?
I'll take a photo tomorrow to show you what I have and where I have got to at the moment.

Thanks again.
Anthony.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 21, 2015, 09:04:32 AM
Hi Antony,
        A couple of other things I forgot to mention:-
           The UPS will take some power even running on no load, so what V and A are going into the unit when its running without an AC load. This is an overhead you just have to put up with.
           The other is what is the output voltage and what is the rated voltage of your heater? I seem to remember that you were talking about a 10KVA UPS which would be significantly under run a 2KW so could well have a slightly high output voltage especially as it has a higher DC input.  If the heater is rated 2KW at 230v and your UPS is putting out 235v then the chances are that the heater is throwing out 2087watts (P = volts squared/ resistance) so you are losing something less than 100 watts which will be a mix of the Power Factor and the standing current needed to make the inverter work any way.
         I would not worry about switching mode power supplies too much unless you have other problems after all that's what all computers use


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 21, 2015, 02:28:49 PM
Hi again,

checked the power taken by the socomec sicom 6kva ups while idling is 64 watts. Ive taken a 2 pics with where i am at the moment, should be with this post.

Do you think its worth starting my own thread with this set up rather that hijack your original, what do you think?

In the photos you will the the socomec ups and additional battery box, the leaf batteries with meanwell power supply, on the top of the batteries is the base where the wiring will be located, you will see the 125v dc 63 amp circuit breakers, one breaker per battery bank, the current shunt,  the programmable volt / curent meter, and cell loggers with cell voltages displayed. Plus the breadboard with the 4N35 opto isolators in readiness for the cell logger alarm outputs circuits.

The battery wiring is done in 60 amp auto grade multi strand flexi cable, very similar to the original battery cabling that is inside the ups battery box. I have looped some of the cables due to excess length, doesnt look too tidy, but read from the net that ideally all the cables have to be the same length to ensure the same loadings are applied to each battery that is connected in parallel.

The cables from the current shunt and dc breakers attach to the rear of the ups battery box via 75 amp anderson connectors.

It is what it is at the moment, what are your thoughts.

Just for info, ive also attached a pic of a 16kwh leaf battery in the back of my prius plug in conversion.

2 of the 3 pics wont load, they are too big, only 750kb though, any ideas


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 21, 2015, 04:11:52 PM
ok, after much reading .....lol..... found a resize app fr win10, so have now resized the other 2 photos for the forum use.

thanks


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 21, 2015, 04:59:55 PM
Hi OK so it looks like a lab workbench experiment at the moment. I suggest that you get some small cable tray (http://www.discount-electrical.com/cables-management-c1/metal-cable-management-c14/metal-cable-tray-c22/50mm-light-guage-cable-tray-3-metres-p1292/s1571?utm_source=google&utm_medium=cpc&utm_term=unitrunk-50mm-light-guage-cable-tray-3-metres-ld50t&utm_campaign=product%2Blisting%2Bads&gclid=COq8uY75ockCFUg8Gwod904ACQ ) and some nylon Tywraps and tidy the wiring up so its all anchored down. Don't use PVC square trunking with the clip on lids, it Burns and gives off toxic smoke. Remember that you are throwing a lot of amps around so those wires need air space around them. Keep the control wiring wall away from power cables and if they have to be near one another cross them at right angles to minimise any cross talk. this is often a cause of untraceable non repeatable faults. Also label each wire several times in its length it will save a lot of time tracing any faults you get.

Don't worry about the hijack we seem to be the only people going down this route your just a few steps in front. Several weeks in and I still don't have any detailed answers from Growatt or their agents. Either something is amiss or they are not to hot on customer relations. This is an interesting picture that I was sent on Face book the other day (http://)


Title: Re: UPS and Growatt SP2000 unit
Post by: roys on November 21, 2015, 05:42:13 PM
 Hi g-1998
Still following this thread with interest, well done to you and bookwoorm.

If I was to be a little critical, sorry, the crimping of your brown wires, they look like about 1.5mm, they should be in a red or blue crimp and get a set of ratchet crimpers.  Using the right crimps and crimpers can save a lot of pita intermittent faults further down the line.
For interest a general rule of thumb:
Red up to 1.5mm
Blue 1.5 to 2.5mm
Yellow above 2.5 to 6mm

If you want me to make you up a small selection pack of crimps and send you them just let me know.

Keep up the good work.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 21, 2015, 06:41:02 PM
hi bookworm, love that picture, so true

For sure yes it is a workbench test project at the moment. I was going to use the automotive type split round conduit to protect the cables and looms, of course keeping the load and control looms apart. get it working and cycling correctly, with all control circuit in, working and set to the parameters.

Hi Roys,

i used those cables only to check that the shunt and programmable controller were working, they were leices of cable i had lying around with the crimps already on, so i used them to try, you are absolutely correct thoungh, and thanks for the kind offer of the terminal crimps, ill pop down to screwfix and pick up a pack of each. Thanks for the input.

I received news off a contact that i have with the strong possibility of another leaf pack in the next 2 weeks, from a 2013 model with 8000 miles covered, not sure if the cells inside are the gen1 or gen2 type, either way they are very good cells. Ive already had 2 packs off him, kept the one myself and sold the other on at modest margin to help with the purchase for me project equipment requirements.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 22, 2015, 09:40:10 AM
Hi Anthony,
     Well I've got some answers from Growatt. The good news is they use a Battery MONITORING System at the cell level on the battery to control the on/off of the charge/discharge, but the main diverter unit only works with Lead Acid or LiFePO4. So I guess it wont handle the extra volts needed for Lithium Cobalt. That's a pity, at 13p /WHr the Leaf battery is dammed good value. I don't want to invent a zero power to the grid put it in the battery system myself if I can help it.

      Growatt haven't yet answered about tapping off the battery to feed another inverter or how batteries are paralleled. That should not be a problem on the DC side but I don't see enough connectors available for the control/monitoring cables. I'll also need to pick up a low battery warning to shut down the secondary inverter.

      I've worked out how to stop a native UPS from trying to back charge the Li battery pack down the DC cables as though it was an SLA. A pchannel MOSFET a zener diode and resistor will act as a very low forward voltage diode so current can only flow from the Li pack to the UPS. An 1XTR170P10P would suit the volts/current I'm thinking of, and only waste about 0.9 watt compared to a power diode which would throw off nearly 80watts I'm looking at a few quids worth of components and a box which I will need for the fuse anyway this a lot simpler than trying to take the innards of the UPS apart.(http://)

      I just need to work out how to add a low voltage turn off to this incase the UPS I get does not have a 'remote off' input. There seem to be plenty of circuits ideas when you Google this sort of thing. I'm in the process of drawing up how I intend to put the bits together so the solar inverter still works and gives power to the property when the grid goes off with out infringing the G53 requirements. The feed through relay in the UPS is essential to this. I'll post the diagram when its tidy.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 22, 2015, 10:41:11 AM
That growatt unit uses a battery labelled a bpi swing 5300, a Boston power product, using google they won the contract to supply Darfon who is a subsidiary of benq who distribute the growatt system.
If you googled Boston power you will find reference to their partnership with benq, and the contract to supply the battery modules for the growatt product.
The battery discharge curve resembled that of a lithium cobalt cell rather than a lifepo4 cell, and it has a non voltage of 3.65v whereas a lifepo4 has a non voltage of 3.2v.
Have a Google, I would need to research the cells in full to have confidence that the product and manufacturer will still be around the honour any warranty period.
A lot of the Chinese cell manufacturers have disappeared leaving a lot of end users high and dry


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 22, 2015, 10:44:12 AM
The beauty of the leaf cells is that if a cell failed, there I'll be plenty of leafs around in the future to replace a whole pack or weak individual cells as there will be more and more leafs appearing in the breakers yards


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 22, 2015, 10:48:24 AM
Hi bookworm,

What would be your ideal system, the growatt battery modules connected to your own ups or a complete growatt system?
The growatt battery module is 100ah @48v, around 5kwh, maybe 4kwh useable, and a max discharge rate of 2kw,


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 22, 2015, 01:33:10 PM
Hi Anthony,
          I see what you mean I also found this http://midsummerwholesale.co.uk/pdfs/sp2000-growatt-battery-installation-guide.pdf. It certainly looks more like Lithium cobalt. but maybe that is more than one battery! being sold this sheet is for the EIA02-002 whereas the ones you see advertised including on 'midsummer wholesale' are GBLI 5001. More questions to ask.
          Just looked back at your other threads and comments from others about change over switches, Something I need to add to my overall schematic.
          An idle power consumption of 64 watts for a 6000VA UPS does not sound too bad. Did you re do your basic trial yet to find out how much the fan heater was actually absorbing when you were putting in 2168watts?


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 22, 2015, 04:05:48 PM
I'd want to know all about the growatt and batteries etc before making a commitment to purchase.mi would have thought if a fault occurs with such a system it s a service engineer call out repair, and won't be able to alter cell parameters etc to reduce depth of discharge etc for your own running parameters etc....

There are many advantages of a plug and play install, but a hefty price is to be paid for the privilege.

At least with a home design, there is the time and effort to design, build and install, but then you have a full understanding of its function and how to repair if a failure occurs.

I would be very interested in duplicating your designs and cut off methods in my own install if that's ok. It's good to have an electronics guy on board as its a very weak point of mine personally.

As far as the socomec sicom 6kva is concerned, the power consumed was 1990 watts with the ups and heater running, with a power factor of 0.99.
This was measured with a plug in type energy meter, not sure how accurate it is but its ok as a reference. As far as the idle running is, well, it's a case of having to put up with that side of things, everything is going to consume precious watts, and if your exporting those watts, better to capture them in our own batteries and suffer the inefficiencies of the systems.
I'd rather this route than maybe 10,000 for a manufactured plug and play system. 10,000 I definately don't have, time and effort I have in abundance, I care full time for my disabled 18 year old son who has cerebral palsy from birth, so these type of things keep my mind occupied and off the daily stresses of caring and worrying for our son.

I hope between us we can build a system that's efficient, effective, useable and above all cost effective. I'll help all I can with batteries and the experience I have had in running them in the Prius for over 2 years, 6 months on the leaf cells.

Anthony.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 22, 2015, 06:05:58 PM
Hi Anthony,
         The reason I looked at Victron, SMA, Nednap Samsung and now Growatt is because these systems natively divert what you would have exported to the grid into a battery. People like Shuco are so expensive you wonder if they will ever sell any kit. There are now some cheaper Chinese offerings out there now but when you look closely their DC connection is a bit of plastic 30 amp chocolate block and that is going to melt at the powers they claim. They also claim to work with all sorts of Battery chemistries but you cant find the details of how they are set up or work.

         Of the more robust Only SMA Sunny Island throttles back the main Sunny Boy PV inverter to charge the battery and minimise export. They only work with Lead Acid. I would have to throw the existing inverters out.

         Victron have a couple of incarnations and I seen their kit in the marine environment it used to only work with Lead Acid. It is primarily designed to boost a poor shore supply when you tie up in a marina but has been re programmed to do the sort of thing we are looking for, however, they have produced a bit of kit that uses Lithium but the battery is rather small. I would have to throw the existing inverters out.

         Nednap's first offering had a software glitch and the only way you can get info from the unit is to let it send gen to their website and then you get it back again which is no good if your broadband goes down. It isn't a backup supply either. I would have to throw the existing inverters out.

         Samsung's offering is pricey and like Shuco I haven't looked to much. I would have to throw the existing inverters out.

         As you say Growatt is part of Benq who look to be a fairly stable company. The unit claims to be able to use both Lithium and Lead batteries and can be retro fitted to an existing system. It works by stripping the DC from the PV until the battery is fully charged then sending the rest to the inverter. If you don't consume all this then the balance is exported. If there isn't enough power coming from the PV then it outputs the battery to the inverter up to the point of zero export or battery depletion. You can buy the unit without the battery which is one of the reasons I'm interested in it and Leaf batteries. There are a couple of variants in the pipe line SP1000 and SP3000. Hence I'm asking them a lot of questions.

         A reason to go for manufactured kit is my age, now I might have 30 years left but who knows and my other half can't cope with the inherent time delay we get on the thermo actuated valves on the UFH ( but she does understand the need to keep the place up to temperature because of the thermal time lag of warming the concrete in the floor up). Just have a thought for who would sort out a problem in your system to keep the lights on for your son if you were seriously ill? Sorry I don't know how bad his condition is. In my old company my accountant had CP and his official way out of the building in the event of a fire was to abseil 40m down the middle of the stairwell - we kept a spare wheel chair at the bottom for him.

         Enough about my reasoning for where I'm going the diagram should tell you a lot more when I finish it and post it.

         Feel free to use the MOFET idea you need to know the peak Source to Drain voltage it has to sustain including any nasty noise spikes and the max surge current it would have to put up with. No use just saying its a 48v system and 100 amps at 6KVA output your charging up to nearer 60v and the spike can be double that. What is the current going to be with a low battery and the surge current to start a 1HP motor at that point well 6KVA when the battery is down to 42volts is 143 amps and a 1Hp motor is 750w with a x7 surge for a few cycles which is another 5250 watts so you would be looking for a MOSFET that can sustain 70V and 150 amp AND a surge of 120v 300amp. There is a reasonable tutorial here https://www.fairchildsemi.com.cn/Assets/zSystem/documents/collateral/onlineSeminars/Understanding-Modern-Power-MOSFETs-PPT.pdf. and mouser have a simple filter list to chose the device you want http://www.mouser.co.uk/Semiconductors/Discrete-Semiconductors/Transistors/MOSFET/_/N-ax1sf?gclid=CMjb5piqnMkCFVW7Gwod8r0CeQ

         I didn't realise until recently that the native BMS on the Leaf pack was split into two with an optocoupler in the middle as well as in and out see http://www.mynissanleaf.com/viewtopic.php?f=8&t=17470 could you use it as is when you get to your 10KVA UPS?


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 22, 2015, 07:03:12 PM
I just browsed the miss leaf bms hack, it's amazing what poeple can do.

I do have the bms here, I utilised some of the power cables in the Prius build but the bms and harness I still have.

It would be very good to learn that if the leaf could be broken into 2 parts, both with 24 cells and 200v would be a good voltage for the 10kva apc ups that I have. It's the big black box you can just see sitting on top of the 6kva iOS in the pic I posted.
Thanks for finding that info, no doubt that thread will expand over the months to a microcontrol master communicating with the can signals and getting charger controls, ah count etc... Link up to a 7" tablet with the elm327 and got a visual display too of the battery in real time. One for the wish list for sure.
On a personal level, my son has quadriplegia cerebral palsy, means all his limbs are affected, he has only just started talking a very basic language with single words, no sentences, he is wheelchair bound, can't feed himself... Etc.. I suppose you can imagine the level of care and input he requires daily.
He has gat a through floor lift to his bedroom, so a back up power supply will prove invaluable in the event of an outage to continue to use the lift to get him into bed etc..... The more I think about it, the more I'm leaning to wards a bigger battery myself now.
Thanks again for your help, I'm sure you and I will find a good working solution for our needs, with their and assistance I'm sure we can progress to a fully working system fit for purpose.

Anthony


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 23, 2015, 09:46:35 AM
Hi bookworm,

I'm in the same situation really, I have 2 Sma inverters that are connected and working with my 7.5kw grid tie kit, and don't want to loose them.
I installed a system for my brother before the summer to divert all otherwise exported energy, it's called the mk2pvrouter by robin emley, it is based on an arduino so can be programmed to do exactly what you want it to. I will need one soon when my meter gets changed but don't need one yet...... If you know what I mean.

When I do get one (as they are very very good units) I'd set it up as so,

If exported energy less than 750 watts, divert to the immersion heater,
If exported energy more than 750 watts, open up output 2 and divert to battery store via meanwell power supply, and excess beyond 750 watts gets exported to the heat store via output 1.
Both ouptuts are triac outputs and fully proportional.
They are very programmable if you know arduino, can add more output as required. I definately will be getting one. If interested pm me on it, as i can give you details vial pm.

My other son, who is a twin to his brother who has the cp, he's ok thankfully and has just started an apprenticeship with Arqiva as a broadcast ans electronics engineer, servicing, maintaining the TV and emergency services broadcasts, he has been with me on these projects so he could manage them in the future.
For sure his education through the apprenticeship especially in the electronics side will help me in the future.

Anthony.



Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 24, 2015, 01:59:21 PM
Hi Anthony,
          Is the meanwell PSU/charger happy getting its supply from a burst firing diverter like the Mk2router? Whilst your system chokes off what might go to the grid, to use that power at some other time you have to manually change over. Also I don't see how you can boost the output of the PV inverter to minimise import when the weather is dull. The Growatt is supposed to do both.

          I've finally got my system diagram together, It probably needs a couple more isolators when I've had time to think about FMEA and I'm pretty sure I'll put in some plug and socket connections as well.
(http://)

          The things requiring unbroken power are connected to the 2nd consumer unit which normally gets its supply hard wired through the UPS. The double pole RCBO's in the main consumer unit and the manual changeover switch are there to make sure you can still feed those circuits on the 2nd consumer unit if any thing in the UPS/PV side gives up. I still need to enable a remote shutdown of the UPS on low battery. I've found a chip that will drive a MOSFET isolator http://www.linear.com/product/LTC4359, which will also stop the native charger in the UPS interffearing with the Li battery. If I can get a battery warning signal out of the Growatt then good if not then I'll need another voltage monitoring circuit across the battery. I might just have one anyway as there is still the potential of excess generation going to the grid. It would give an inhibit input into a Mk2 router so that it does not turn on while the battery is still charging. I could then heat some towel rails electrically in the summer rather than flashing up the gas boiler.

           I like this design because it  takes power you would other wise export and uses it to either boost the PV output for a net zero import and it is extendable. If you have a second set of panels facing a different direction, which is something else I'm after if the planers allow, then you just need another Growatt, battery and reverse feed protection circuit. Once its set up you can leave it to its own devices.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 24, 2015, 07:47:24 PM
Hi bookworm,

Lovely diagram that is.

May I ask what the function of the growatt is.
I ask as it won't work in my situation, in that, if the solar pv is directed to the growatt, and some power goes into the batteries and some into the grid tie inverter, that's great, however, my grid tie inverter has an energy meter  on the AC output side that clocks up the generation units, if some of that power is put into the battery directly of the solar pv, then that will reduce the quantity of feed it tarrif payment.
Maybe you are not considering a fit payment, if you are then how do you get that pewer that has been put into the battery recorded as a kWh for payment purposes, as some will inevitably be taken np by the ups on dark nights without registering it throughout the energy meter for fit purposes.

The meanwell psu should be ok functioning on and off repeatedly, but I have got 7.5kw of solar with another 3 kW too soon hopefully, so should be well over 750 watts most of the time from March onwards.
I suppose the system could run like this perhaps,
Leave the ups on and ready to provide energy from the battery, all the time, when the solar pv is providing less energy that demand, the ups steps in and takes up the additional requirements, and more will get diverted back to the ups via the pv router, and so on etc, not very efficient I know but it could be done.
I see it thought as a night time provision with a manual switch over, yes it's primitive but until such a time this hybrid kit becomes affordable, it'll have to do, there is no doubt in time I will for sure have a system that will be fully automatic in the future, but prices will have to fall considerably first. The early adopters always get stung, maybe in 3 or 4 years time this equipment will be freely available at reasonable prices.
Anthony.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 25, 2015, 09:00:02 AM
Hi Anthony,
      Yours is a common misconception about the Growatt SP2000. When the output from the PV is low or non existent, it boosts the input to the solar inverter from the battery (assuming there is capacity left in the Battery) up to the point where export/import is zero or the max rating of the inverter is reached. So if I don't have a mains failure then everything from the panels goes through the Generation meter eventually. There are naturally some losses but as my panels are bigger than my inverter I will still get more out than I do currently. Anyway with FITs falling through the floor you are only sensibly going to get paid for what you export so it is better to give up the 5p/ unit exported and use it yourself rather than buying at 15p/unit.

      Now conventionally when the mains fail you inverter stops and you are loosing those units that the PV would have generated. The only generation units I loose are those the UPS steals from the battery when the mains fails and the UPS inverter fires up, but I don't lose those units that the PV produces during a mains failure because the solar inverter will re sync to the UPS then depending on the load on the 2nd consumer unit either
a) there will be enough solar power to top up the battery and power the house with the UPS just providing the 50Hz sync, that output gets metered.
b) there isn't enough sun and the Growatt boosts the Solar inverter, that gets metered too.
c) its dark the and the UPS steps into the breach. That bit of power I loose.

      Under Mains failed condition to get the solar inverter to take the lions share of the load and the UPS to only provide the sync signal I will have to set the output of the UPS down to 220 volts. Like that the natural behaviour of the Solar inverter will go to a higher voltage because it is designed to push power into the grid and it will provide more power than the UPS. That is a balancing act that will require some experimentation at different loads.

      The only way of getting all the possible units through the generation meter is to have a separate battery for the UPS which is charged from the AC side of the supplies not the DC.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 25, 2015, 02:16:05 PM
      The only way of getting all the possible units through the generation meter is to have a separate battery for the UPS which is charged from the AC side of the supplies not the DC.

I'm sure some could do similar, charge the battery from mains at 15p and clock up the gen meter and sell it back at 48p if on the original tarriff. Not that I would do such a thing of course.


Title: Re: UPS and Growatt SP2000 unit
Post by: Sprinter on November 25, 2015, 03:10:04 PM
When i originally toyed with the idea of the Growatt i though that i read that the max battery size was 100AH for Lithiums and 150 for lead based batteries, but you guys seem to be talking about putting a great deal more batteries behind the P2000 unit.

Have i missed something or is the recommended 100 150 AH battery systems just that, a recommendation rather than a maximum capacity?


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 25, 2015, 04:53:20 PM
Hi sprinter,

Bookworm is going down the growatt route, I'm not fully conversant with the specs, I know bookworm has been in contact regularly ironing out the spec details with them.

I'm purely going down the battery and ups route until this equipment becomes more affordable for me at least.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 25, 2015, 05:49:45 PM
        As far as I can make out the Growatt SP2000 is limited to a 2000watt charge/discharge rate so that is 40 odd amps. A bigger battery will just take longer to charge. They only offer any warranty with their own battery.
        I've got an hour by hour spreadsheet  with actual solar input and house usage for the last 5 years and if I could have had one of these units 5 years ago I would never have hit that limit. I've also made a variant of what the input would have been if I had 4KWp of panels and that only hits the limit for a couple of hours. There are admittedly a number of times each summer where I would be exporting because the battery was full and this gets worse with more panels. You would need something in the order of 2MWHr battery to be in a position where you don't export anything and even that battery would only be fully charged 21% of the time and fully discharged 22% of the time. With a 4KWp PV two Growatts SP2000's and a full reconfigured leaf battery I would be at full charge 20% of the time and full (80%DOD) discharge 27% of the time.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 25, 2015, 06:01:25 PM
I've just got some more answers there is going to be as SP1000 available in January for the 1800 mark including battery (not sure if this is the Wholesale price ex VAT). It's a down rated SP2000 with the same battery??? That throttles the charge /discharge to 20 odd amps. It makes me a bit suspicious as the wholesale price for the battery on its own is currently 1700. I wonder what has being giving them trouble? There is also an SP3000 on test at the moment which is supposed to be released Q3/4 next year.

The BMS is said to be a monitoring system not a management system tough they still haven't answered the $64,000 question about shunt resistors.


Title: Re: UPS and Growatt SP2000 unit
Post by: jonesy on November 25, 2015, 06:18:11 PM
Under Mains failed condition to get the solar inverter to take the lions share of the load and the UPS to only provide the sync signal I will have to set the output of the UPS down to 220 volts. Like that the natural behaviour of the Solar inverter will go to a higher voltage because it is designed to push power into the grid and it will provide more power than the UPS. That is a balancing act that will require some experimentation at different loads.
Some things that occur to me.  The growatt gets its info from the clamp. With no mains import/export there during power fail, how will it know what to deliver.
The synchronisation of the solar inverter (GTI) with a UPS has been discussed to death and largely abandoned* due to the way a GTI normally operates.  However, if the growatt can just provide enough power to the GTI so there is no surplus, theoretically. If there is an excess (and there will be, as you have 2 closed loop controls there 1. UPS 2. growatt & GTI), there are 2 possibilities. The UPS objects to the power in, and blows the H bridge mosfets, or the UPS changes automatically into charge mode and charges the battery.
I don't think setting the UPS voltage down will change anything, as the GTI aims to export at just above the mains level ie current only flows between a voltage difference.
Check your GTI isn't the HF type, as IIRC the panels ie the growatt/batteries? are not always isolated from the mains. SMA have a guidance doc.
I personally wouldn't fit RCBO on the UPS/change over feeds.  Some GTIs specify RCDs where the panels aren't isolated, but I've not come across anything for UPS. The RCD reduces the availability. If you want one, you'll need to use either larger or time delay upstream to give discrimination.
Depending on your house earthing scheme, you must ensure that UPS is hardwired.  If not, if the supply plug becomes lose when on load, you will the board neutral/earth connection, thus leaving you with a floating mains system.
The fault current available from either the GTI, or UPS (or both) will be pretty low. What this means in practical terms is that a live to earth fault on a 32A breaker on a ring main will not clear in the prescribed 0.4s.  Possibly never, and IIRC you are not permitted to rely on the RCD to perform that function, but it probably would. Have a look at the sunnyisland for typical breakers - it'll be say 6A/type B.
Even if all your various items growatt/ups/gti are electrically isolated, each will have leakage currents through the (HF) transformers.  Whilst I'm not an advocate off earthing battery packs, you probably need to think about if and how you are going to keep one terminal near earth.
Interesting thread this.

*there is a successful modification of a UPS for off grid use here http://www.fieldlines.com/


Title: Re: UPS and Growatt SP2000 unit
Post by: bxman on November 25, 2015, 09:51:07 PM
Have either of you looked at the Nedap ?

I think most problems have been sorted out apart from their strange battery voltage  management ideas  but they are resolvable so I am informed .


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 26, 2015, 03:58:56 PM
Hi Jonesy,
          Firstly I'm asking a lot of questions of the Growatt guys and the subject of tapping off their battery for a UPS and marrying a UPS with the GTI will  go to their designers in Shenzhen once I've got a non disclosure and design rights agreement back from them. I don't mind if they eventually exploit the idea provided I get a royalty for it.

          This will be a hardwired system. Most UPS that I've come across earth the -ve terminal of the battery in the bridge and the AC floats, reliying on external bonding to the neutral. So how the GTI is earthed is a relevant question. Does anybody know how the Fronius IG series are wired up. That's what I've got at the moment. Getting the balance of power output right between the UPS and the Solar inverter is a matter of impedances and paralleling generators. I've seen multiple UPS's with paralleled outputs before. As the UPS has got to handle some motors without the benefit of soft start it will be rated far bigger than the mere arithmetic sum of the loads.

Hi bxman,
          I walked away from Nedap a couple of years ago because they would not release their control/monitoring software for 'local use' Everything had to go to their server and back again.  There are 2 problems with this, the user is relying on at least two third parties one of whom (BT) does not give a dam about somebody elses' operation critical control signals and what happens when Nedap go to the wall as a business or decide to stop supporting the product!! Didn't this happen with Encsys or have I got the wrong company. Nedap might not have been the most expensive but they were twice the price of some of the others.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 26, 2015, 06:11:00 PM
My neighbour and friend had the enecsys inverters fitted with his solar pv. He isn't technical at all, and last year he knocked my door to say that all his inverters were off line and he couldn't tell if any of them were not operating as he had no way of interrogating them as the enecsys servers were now off line.

He has had 3 inverters fail too so this worried him greatly.
I did some research on his behalf and found freeware software so he could monitor his inverters locally himself. He was very appreciative to me for helping him out.

So it goes to show, local monitoring is the only way really, enecsys and nedap  have for sure taken the wrong road with that decision.


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 27, 2015, 04:06:26 PM
Hi Jonesy,
        I hope you di not think that yesterdays response trivialised the points you bought up on paralleling a UPS and Solar inverter, far from it, its just that I think the subject requires a more considered reply. The behaviour of the two units when coupled is something that I have on my list for a proper FMEA. There are a couple of learned papers on the subject of parallel operation of UPS's etc that use inductors for load balancing god knows what that does to power factors I need to do some reading up. Trouble is ones paper is in Spanish and the other in Danish, I have yet to find versions in English, when I can get hold of them I might understand the formula and form a view on the suitability of the ideas.

        I am already including a MOSFET and a LTC4359 control chip as a super diode in the battery supply to the UPS. This protects the battery from the UPS's inbuilt charger and the UPS from reversed battery connections. It should also stop a back feed through the inverter from the AC side. People tend to forget that once there is a positive voltage difference between gate and source on an N channel MOSFET that current can flow in either direction so I guess your worried that the bridge circuit will act as switched diode bridge when the GTI tries to push excess power into the UPS. One way that I have in mind to stop this is to use the Growatt's natural abilities to reduce both import and export to zero. This could be done under emergency conditions if there was a CT between the UPS and the 2nd Consumer unit. How to switch between the two is currently exercising my mind as I would need to tap into the UPS's transfer signals, but I don't want to ask questions about the CT's circuitry until the 'non disclosure' agreement is in place.

        On the subject of protection; Some of what I have seen so far appals me and even the best is not as good as it could be. BS7671 calls for UPS's to be able to operate distribution circuit protection devices (para 560.6.11). Now if you are feeding a 32amp ring main from a 2KVA UPS then you've got a weasel pee poor design anyway and I agree the breaker probably would not trip.  Glyndyr1998 is using 6KVA and 10KVA UPS's so it is something he needs to carefully think about with the smaller unit but the bigger one will be ok. For myself I'm looking at a 3 or 4 KVA UPS feeding radial distribution circuits (Rainwater pump 4 amp, a couple of fridges/freezers an amp, Solar Thermal system controls another amp, CH boiler controls 2 amps and ethernet routers another amp) There are 5 motor start currents to be accommodated but the chances of then all cutting in at the same time are remote. I've initially chosen RCBO's in the main consumer unit for the AC input to the emergency system because you need to protect the other circuits in the house from the UPS etc playing silly buggers. You don't want an earth fault/line neutral imbalance in the emergency circuits throwing the whole board off. However given the high failure rate on RCBO's and the need for double pole isolation I'll probably change them for a RCCB and individual MCB's.

        On the question of Mods to UPS's I've heard of the field lines web site but I never been able to get in to it do you have any other references. Also if you have any other relevant thoughts about what should go into the FMEA please let me know.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 27, 2015, 06:47:45 PM
Hi bookworm,

you have obviously put a great deal of time and thought into your system, I don't know what your experience is, but it sounds considerable, I'm mechanically biased myself so most if not all of what you discussed in the previous post went woooshhhh straight over my head.

I will not run my ups in tandem with the inverter, I haven't got the skills to integrate it smoothly or conduct a trial and make electronic mods to counterbalance any issues arising from the possible integration issues of the equipment.
Hence, I shall manually disconnect my mains from the grid in the night time and run the house from the ups using light loads only.

I'll use the 6kva initially, as its nearly ready to use, and I will install the 10kva ups when I get hold of another leaf pack to work with it.

I shall then probably sell on the 6kva ups complete with the 7.5 kWh leaf battery and my own built protection circuitry and equipment.
When do you think you'll be informed with sufficient information to take the plunge and purchase the equipment and start on the installation? I'd love to see a few pics of it when it's installed.

Anthony.


Title: Re: UPS and Growatt SP2000 unit
Post by: jonesy on November 28, 2015, 02:09:47 PM
There are a couple of learned papers on the subject of parallel operation of UPS's etc that use inductors for load balancing god knows what that does to power factors I need to do some reading up.
If you manage a (google) translate I'd be interested in a look.  With the growatt installed, you change the GTI sort of into a controlled supply, so paralleling is possible.  Otherwise a GTI isnt parallelable (is this a word?) It's an all or nothing device. With 2 paralleled, common sync, UPS, even if the load share is unequal, one does not back feed the other. The GTI could still push power into the UPS and reverse it.  Whilst I'd missed the fact that the battery is blocked, this would not necessarily stop the UPS trying to go into charge mode. It will depend how the UPS responds to reverse power.  I've only seen one reference to it on fieldlines (which seems to have been down for a week now) I'm still at a loss as to how the GTI maintains islanding when the powerjack ups is in charge mode; maybe it only checks at start up.
As I'm risk adverse, I'd say a 'normal' ups would not respond well to reverse power, because the internal CT/software won't be looking for it, or worst still will sum the 180 deg import.  
In terms of inductance and PF, I'd say you'd need some pretty enormous ones to affect PF.

This could be done under emergency conditions if there was a CT between the UPS and the 2nd Consumer unit. How to switch between the two is currently exercising my mind as I would need to tap into the UPS's transfer signals, but I don't want to ask questions about the CT's circuitry until the 'non disclosure' agreement is in place.
Could you add a double pole switch to the power transfer switch?
       On the subject of protection; Some of what I have seen so far appals me and even the best is not as good as it could be. BS7671 calls for UPS's to be able to operate distribution circuit protection devices (para 560.6.11). Now if you are feeding a 32amp ring main from a 2KVA UPS then you've got a weasel pee poor design anyway and I agree the breaker probably would not trip.  
A lot of people just do what they always do. You can meet 560.6.11 by fitting a suitable breaker after the UPS.  No discrimination, but that's not necessarily a electrical safety issue.
Using radials as you suggest is sensible and avoids the on/off grid change of protection requirements.

Just thinking out loud, I'm not sure I'd even use the GTI/growatt during a power cut. The ups can handle everything. Plus if there is some unexpected operating between the devices, you could end up trashing the ups & gti, so you lose income when the power returns, pending gti repair. You would lose the FIT on the element 'off grid' - fairly trivial? It's all about the risk of the event happening and the risk of an incident during that period!

I'll have a think about the FMEA. Do you have a starting point of standard terms? I've spent days discussing them only to find a peculiar problem downstream caused by something out of the norm.



Title: Re: UPS and Growatt SP2000 unit
Post by: rogeriko on November 28, 2015, 09:22:37 PM
Why all this talk about inneficient UPS's forget them, just use a Sunny Island and everything will work perfectly.


Title: Re: UPS and Growatt SP2000 unit
Post by: biff on November 29, 2015, 12:12:26 AM
Hi Roger,
      It might be the price and also the desire to recycle. ;D
                                       Biff


Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 29, 2015, 11:45:34 AM
Recycling yes. Sunny Island only works with a sunny boy inverter you can't retrofit it to another existing system and apparently it is only compatible with lead acid.


Title: Re: UPS and Growatt SP2000 unit
Post by: rogeriko on November 29, 2015, 12:07:03 PM
Sunny Island can control several different inverters with frequency shifting. It can also control ALL inverters if you use the battery voltage to control dump loads. If the Sunny Island cannot shut down or limit your inverter at least it creates a proper grid and can accept the exess GTI output to charge batteries. Battery voltage can be controlled by switching loads AC or DC. Simple.


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 29, 2015, 12:48:06 PM
I for sure haven't considered the sunny island purely down to cost at the moment, it's as simple as that for me.

When the costs come down and more users share their experience with them, how they are operating in real life use terms not brochure terms, how they do integrate with other equipment without comms or teething issues, and their capabilities to utilise lithium battery packs... This is the information that I would like to read.

There is a guy on the photovoltaic forum in Germany that has cuccessfully utilised quite a few Nissan Leaf battery packs with a sunny island, but he also had a sunny boy inverter. He is using them successfully.

I'd like to know how the island communicates with non Sma equipment and how the frequency shifting is set up and controlled.
Thanks.


Title: Re: UPS and Growatt SP2000 unit
Post by: rogeriko on November 29, 2015, 01:33:18 PM
The Sunny Island gradually increases the grid frequency from 50 to 52 as the batteries are charged. The Sunny Boy sees the increase in frequency and lowers its output accordingly, at 52hz it has cut the output to zero so no problems overcharging the batteries. As soon as a load is turned on the battery voltage drops, frequency changes and the Sunny Boy kicks back in to cover the load. Obviously this can only occur in an off grid situation. Sunny Islands are huge in Germany because the Gov't gives subsidies for battery storage. An interesting document from Enphase describing how to connect their microinverters to an off grid battery system. If your grid tied inverter dosnt support frequency shifting then a dump load setup is required.  Victron inverters could be used as well not just SMA gear.

https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwjox9n_2bXJAhUGORoKHbtGBx4QFggmMAA&url=http%3A%2F%2Fwww2.enphase.com%2Fglobal%2Ffiles%2FEnphase_Application-Note_AC-Coupled-Battery-Based-Systems.pdf&usg=AFQjCNHr2BZQODoZ_itEVP1sIHd6cnO6Cw&sig2=1nsdGFTsZygQ6lQvbYhG9Q&cad=rja


Title: Re: UPS and Growatt SP2000 unit
Post by: glyndwr1998 on November 29, 2015, 03:51:25 PM
Hi roger,

I'm hopeful that in 2 years these sunny islands may have reduced in cost to a level where're becomes practical and affordable to make a judgement call to opt to go over to that system.

I do have sunny boy inverters, I have a sb3800 on an East facing 3.5kw array, and I have a 4000tl with a 4 kW west array, both are grid tied and have consent off dno for a 7.5kw connection. I've also got plans for an additional 3kw utilising a abb 3.6tl inverter, I can't use that to the grid, so have to look at integrating an off grid with that. I've seen a few cheap Chinese hybrid off grid type inverters that look good value but the quality is very questionable that's why a ups is an option at the moment for me as I picked them up at a good keen price, but they are good quality well made reliable units.
Ideal for me at the moment to give me an option in the home if and when a power outage occurs to allow me to continue using the disabled equipment I have at the home like the through floor lift to get my disabled son into his bedroom.
Thanks for your input and help.

Anthony.



Title: Re: UPS and Growatt SP2000 unit
Post by: book_woorm on November 29, 2015, 04:31:45 PM
Hi Rogeriko,
        Interesting what you are saying about Sunny Islands I can understand how frequency shifting would work when islanded. However what happens in a grid connected scheme with Sunny Boy/Sunny island set up. Can the pairing reduce the power you export to nothing and put it in the battery (I'm assuming the battery needs charging). Similarly (when there is capacity in the battery) can it take power from the battery and/or panels and boost the grid supply to the property so you import nothing? The Sunny Island will never raise the frequency in a grid connected system there is just too much inertia and I can't see how it works.

         I rather got put off SMA by the lack of knowledge of the guys they had on their stand at EXCEL a few years ago. I don't want lead acid anyway as I had to sort out a rather frightening experience once with a battery bank that was not as well ventilated as it should have been. I would rather deal with superheated steam than an acid fire.


Title: Re: UPS and Growatt SP2000 unit
Post by: jonesy on November 29, 2015, 06:04:44 PM
The software in the newer SI operates in what could be described as an interesting way. The way to avoid the interesting operation is to only connect SMA gear to the battery.  If the SI cannot control all of the battery aspects it puts the off grid frequency to 60Hz when it detects a rising battery voltage. It thinks that the over voltage is coming from connected GTIs, so puts the frequency up to turn them off.
Iirc there are competitor SI products which merge the battery, pv, genny, grid etc.  I did look at the SI about 5 years ago, but the cost was too much.  It'll come down in due course.