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Energy/Electricity Storage and Use/Grid Connection => Off-Grid, Batteries & Inverters => Topic started by: dan_b on May 08, 2017, 09:57:38 AM



Title: My PowerVault - small milestone
Post by: dan_b on May 08, 2017, 09:57:38 AM
So my PowerVault experiment continues, and in April it passed a small milestone - I got 100kWh of electricity back out of the unit for the month.  Always nice to have a big round number like that - am approaching 300kWh in total now since install too.  Feels like the summer months from April-September will be nice and solid.


Title: Re: My PowerVault - small milestone
Post by: dan_b on August 20, 2017, 02:59:23 PM
If anyone's interested, here's what my PowerVault has discharged these last few months.
Jan - 30.67kWh
Feb - 31.25kWh
March - 74.02kWh
April - 102.88kWh
May - 97.14kWh
June - 103.94kWh
July - 94.27kWh


Title: Re: My PowerVault - small milestone
Post by: Tombo on August 20, 2017, 03:30:09 PM
Hi Dan,
How much power has been fed in to it?
Thanks


Title: Re: My PowerVault - small milestone
Post by: dan_b on August 20, 2017, 03:33:35 PM
Eer, pass, sorry! PowerVault claims a 80% round-trip efficiency for my battery chemistry, so I suppose you could work it out from that?

I know how much my SolarPV generates per-day/week/month too, but again that doesn't taken into account how much the house uses before the PowerVault sees the spare electrons.


Title: Re: My PowerVault - small milestone
Post by: smegal on August 20, 2017, 04:00:42 PM
If anyone's interested, here's what my PowerVault has discharged these last few months.
Jan - 30.67kWh
Feb - 31.25kWh
March - 74.02kWh
April - 102.88kWh
May - 97.14kWh
June - 103.94kWh
July - 94.27kWh

Thank you for posting that information. It's good to see a real world example.

Is your ImmerSUN still providing a lot of heat as well?


Title: Re: My PowerVault - small milestone
Post by: TheFairway on August 20, 2017, 06:07:03 PM
What are your equivalent import figures?

How much do you think you are limited by battery capacity/discharge rates?

Your winter month figures are probably better than I could achieve due to shading/pitch but i would like to think I could eek out a bit more than that in shoulder/summer months with a battery with more capacity, except with some of the recent weather patterns lasting several days.


Title: Re: My PowerVault - small milestone
Post by: dan_b on August 21, 2017, 01:16:05 PM
Here are my 2016 vs 2017 import figures in kWh

Jan 368   vs    285
Feb 221   vs    254
Mar 249   vs   177
Apr 153   vs   85
May 163   vs   84
Jun  145   vs   72
July  123  vs    72!

So a definite real dent in my import.

2016 vs 2017 ImmerSUN figures

Jan 14.9   vs    1
Feb 21.9   vs    3.3
Mar 35.6   vs   9.9
Apr 51      vs   54
May 88     vs   55.9
Jun  84    vs   79.1
July  122  vs    69

As you can see, the ImmerSUN has taken a significant hit in the low months Jan-Mar, but once April hit, there has been enough surplus generation to cover self-consumption, charge the battery and divert to the hot water tank.  No gas for the hot water from late April to now. 


I know I'm limited a bit by discharge rate - for example when the electric oven is used to cook, and if several other big-ticket items are all on at once we can trip over the 1100W limit and import, but it's pretty good otherwise.  I think the fact that hte charging is limited to 800W helps keep the ImmerSUN active too.     I can see though that I'm limited ultimately by usable capacity of 4kWh.  Might have to look at hacking the unit once I'm finished with the UKPN trial and seeing if we can add some extra batteries :)



Title: Re: My PowerVault - small milestone
Post by: TheFairway on August 21, 2017, 04:36:56 PM
Thanks. That's a useful set of data.


Title: Re: My PowerVault - small milestone
Post by: dan_b on September 13, 2017, 10:15:45 AM
Bit disappointed this morning to say the least.  Here's the story...

Last week I had a call from PowerVault saying they wanted to run a full charge-discharge cycle on my battery as a diagnostic maintenance check, so could I give them permission to access my battery remotely and basically consume 4kWh of electricity from Midnight last Monday to test it.

This morning I just got a call saying the results of the test show that my Lead Acid batteries are already worn out and need replacing after just 9 months!  They claimed they received a faulty batch of batteries from their supplier and will replace them under warranty next week, with a different battery from a different supplier (Gel apparently?) but that doesn't exactly bode well does it.  The warranty re-starts with the replacements, but I must admit I'm feeling like I made a bad decision at the moment to go this route! 

I guess if they burn out every 9 months and they keep replacing them under warranty each time it doesn't really cost me anything and keeps my batteries fresh, but that doesn't feel sustainable... I did ask if they could swap them for Lithium free of charge as part of the replacement, but alas not.

I'm off to drink some coffee. Will use my 1kW kettle to make the hot water. At least the sun is shining and my panels are putting out 1.68kW at the moment, so that'll be a green cuppa...



Title: Re: My PowerVault - small milestone
Post by: Tigger on September 13, 2017, 10:36:16 AM
Dan,

Relax, seriously. 

Your supplier has put their hand up to supplying faulty equipment and is replacing them free of charge AND restarting the warranty from the date of change.

You don't seem to appreciate how lucky you are, there are hundreds if not thousands of people out there who long for service half as good as you're getting.

Now ring them up and say thank you for being such an excellent supplier  ;D

Ian.

p.s. I am in no way connected to PowerVault, just in case you were wondering......



Title: Re: My PowerVault - small milestone
Post by: dan_b on September 13, 2017, 10:39:42 AM
Yeah, you're absolutely right -  their customer service on this is spot on, they pro-actively raised it with me.  I'm chilled  :cross


Title: Re: My PowerVault - small milestone
Post by: Tigger on September 13, 2017, 10:43:05 AM
Of course, we'll all have set a marker in our diaries for 9 months from now to watch out for a post from a very angry dan_b  whistle


Title: Re: My PowerVault - small milestone
Post by: dan_b on September 13, 2017, 10:45:00 AM
LOL!

Here's a video of batteries exploding in slow motion

https://www.youtube.com/watch?v=cnaYtU_CiJ4


Title: Re: My PowerVault - small milestone
Post by: dan_b on September 19, 2017, 12:35:41 PM
So have got 6 of these going into my Powervault at the moment, anyone know much about them?


(https://s26.postimg.org/a4hltgqnp/IMG_4299.jpg) (https://postimg.org/image/a4hltgqnp/)

(https://s26.postimg.org/57418cool/IMG_4300.jpg) (https://postimg.org/image/57418cool/)


Title: Re: My PowerVault - small milestone
Post by: RIT on September 19, 2017, 04:31:06 PM
So have got 6 of these going into my Powervault at the moment, anyone know much about them?


(https://s26.postimg.org/a4hltgqnp/IMG_4299.jpg) (https://postimg.org/image/a4hltgqnp/)

(https://s26.postimg.org/57418cool/IMG_4300.jpg) (https://postimg.org/image/57418cool/)


Only the details posted elsewhere, such as at

     http ://www.alpha-batteries.co.uk/12v-110ah-leoch-powabloc-tubular-gel-battery/

And only the PDF sheet makes any real sense as it indicates a 40% loss of capacity if you cycle 1,700 at 70% DOD, not something shown in the rest of the text. This figure does at least fit within the stats used by Powervault, even if Powervault does not make any statements regarding long term capacity. Their quoted Tubular Lead Acid warranty only kicks in if the battery drops below 50% capacity, which would indicate it's become scrap and even then they only really offer a discount off their replacement parts.


Title: Re: My PowerVault - small milestone
Post by: dan_b on September 19, 2017, 05:10:52 PM
They're physically bigger and heavier than the batteries that were removed - the engineer said they weighed about 3kg more each than the others. 


Title: Re: My PowerVault - small milestone
Post by: RIT on September 19, 2017, 05:49:13 PM
They're physically bigger and heavier than the batteries that were removed - the engineer said they weighed about 3kg more each than the others. 

Which should indicate that the plates (well tubes) are thicker than those used in the old batteries - always a good sign.

Were the old batteries branded? Or were they some no-name product that PowerVault may now be regretting trying.


Title: Re: My PowerVault - small milestone
Post by: TheFairway on September 19, 2017, 06:02:50 PM
Is your 4kWh (your sig says 4kW) taking into account (say) 70% DOD or you you really only have usable 1.2kWh before you reach the 70% DOD mentioned earlier where capacity is severely limited.

Or does some other process prevent loss of capacity after a relative short period of time?

Or am I confusing 70% DOD as 70% capacity remaining ie 30% usable, instead of 30% remaining, 70% used.

Even if latter, 2.8kWh capacity would still only be a small percentage of daily usage. But theni guess, from DNO perspective, its not about powering for long periods, its about smoothing demand.


Title: Re: My PowerVault - small milestone
Post by: dan_b on September 19, 2017, 07:03:50 PM
The original spec of the LA AGM battery i got supplied with was an 8.8kWh battery pack, with a warrantied usable capacity of 4kWh down to 50% DoD for 800 cycles.
It looks like these are Tubular Gel batteries? According to PowerVault that should be a 5.kWh pack with a usable capacity of 4kWh down to 70% DoD for 1800 cycles.
Do we think that's reasonable?  With 6 of these in there, is that the right maths?

I didn't manage to snap any pictures of the old batteries, so don't know what make they were.


Title: Re: My PowerVault - small milestone
Post by: RIT on September 19, 2017, 08:32:43 PM
The original spec of the LA AGM battery i got supplied with was an 8.8kWh battery pack, with a warrantied usable capacity of 4kWh down to 50% DoD for 800 cycles.
It looks like these are Tubular Gel batteries? According to PowerVault that should be a 5.kWh pack with a usable capacity of 4kWh down to 70% DoD for 1800 cycles.
Do we think that's reasonable?  With 6 of these in there, is that the right maths?

I didn't manage to snap any pictures of the old batteries, so don't know what make they were.


With 6 of those, I think you have a very good long-term deal. It also seems that PowerVault is leaves a lot of slack in its specs as those batteries provide 5.8kWh with a C5 rating and 6.5kWh with a C10 rating, which seems to be the operational rating they use in their specs (6 x 90Ah)


Title: Re: My PowerVault - small milestone
Post by: dan_b on September 20, 2017, 10:16:40 AM
Managed to discharge 4.75kWh from the new batteries last night which is interesting considering they were only commissioned at 2pm yesterday afternoon.  I assume they must have been fully charged when delivered?

It's all a learning experience...


Title: Re: My PowerVault - small milestone
Post by: TheFairway on September 21, 2017, 06:13:06 PM
Out of curiosity, did you need to get G83(?) permission. If so how long did that take?

I was speaking to Tesla today and was surprised that it needed G83 or higher permission depending on what level the Powerwall output is capped - 3.6kWh or 5.xkWh - and that took some time to arrange. Apparently batteries are a bit of an education topic for the DNOs.

Also, the function to time shift charging is a UK only option, and will be available via software update later this year. But the battery backup functionality will not be available in UK until later 2018 - iirc its available in Aus now as it was primarily developed for that market. But that adds more boxes and cost to the install - advised it probably would not be worth it in UK as grid stability for most is good - still like idea of having lights on during a power cut to impress the neighbours - how vain!


Title: Re: My PowerVault - small milestone
Post by: dan_b on September 21, 2017, 07:11:06 PM
No grid permission was required or even mentioned.  Maybe the very high output power of the Telsa PowerWall (which can hit 7kWp with 5kW sustained) has something to do with that?  My PowerVault only outputs at up to 1100W, so nowhere near the 4kW solarPV connection restriction.

Funnily enough my PowerVault was installed as part of a trial being run by my DNO specifically to look at the impact of domestic-size batteries on the local network.  The UKPN Trial includes battery systems from PowerVault, Sonenbatterie and a couple of Tesla PowerWalls, so they are looking at it.

PowerVault has an option to re-charge overnight on low-tariff electricity.  In fact they're running a trial with one of the utility firms (Tonik I think) to see what a good time-of-use tariff looks like for domestic battery owners, and whether they can actually offer it as a package deal.

The recent video about the PowerWall on FullyCharged talked about Tesla developing a module that would allow you to use the battery as a house back-up in the event of a powercut - it's certainly not availble in the UK at the moment.  The PowerVault actually has 1x 13A socket on the front panel to which you can connect a device and it will power that in the event of a powercut - maybe a fridge or something...


Title: Re: My PowerVault - small milestone
Post by: RIT on September 21, 2017, 07:11:40 PM
But the battery backup functionality will not be available in UK until later 2018 - iirc its available in Aus now as it was primarily developed for that market. But that adds more boxes and cost to the install - advised it probably would not be worth it in UK as grid stability for most is good - still like idea of having lights on during a power cut to impress the neighbours - how vain!

Well if all the doom and gloom merchants are right I can see another use for battery backup/home isolation. Their claim is that with all the PV being installed local areas will see their voltage rise so much that the PV inverters will start to back off and so cause stability problems as they keep switching on and then off. I get the feeling that the real chance of this is sod all, but if you have a nice isolated house you can just disconnect and get on with life.


Title: Re: My PowerVault - small milestone
Post by: M on September 21, 2017, 07:40:32 PM
The DNO 'stuff' threw me a while back, till I realised it was the control of excessive export issue again. I wonder if the Powerwall 3.68kW takes the PV system into account, or if under some very odd circumstances they could both be exporting? Though of course, why empty your batt to the grid, but what if we're being paid for it, but then why would the grid be desperate for battery discharge if PV gen is high ...... head hurting!

I've got a 5.9kW export limit, so I wonder how that applies to the batt, if at all.

Fun times ahead, again.


Title: Re: My PowerVault - small milestone
Post by: Tiff on September 21, 2017, 09:25:14 PM

A power wall/vault system is an embedded generator and in theory treated the same as a PV system of the same TIC with regard to DNO and G83/G59.

Dan - I'm really not surprised those lead batteries failed, I don't think they are suitable for a powerwall type system, lithium batteries are vastly better for a powerwall application. It would have been interesting to monitor the SG of the lead batteries over that time rather than voltage.

Sounds like they have used better batteries as a replacement so maybe you will get 12 months out of this set. Rinse and repeat the warranty replacements until the end of warranty and then get some nice LiFePO4.


Title: Re: My PowerVault - small milestone
Post by: dan_b on September 22, 2017, 08:35:40 AM
Tiff, what does SG mean?
They have replaced them with a different type of LA battery it would seem yes, so we'll see. As you say though, if I end up burning through another set within the warranty period and they replace them again I'll be doing ok - just not particularly green is it!

In the 3 days since the new batteries have gone in, the daily diversion is at least 1kWh/day higher than before.


Title: Re: My PowerVault - small milestone
Post by: Tiff on September 22, 2017, 09:05:17 AM
SG - specific gravity. The most reliable way to tell the state of charge. The problem with lead acid in this type of use, especially if deep discharges are a regular thing is that the batteries may not be getting a full recharge often enough. That last 5-10% of charge on lead can take some time and is also very inefficient, a lot of the input energy is just used to make bubbles. Once the lead is fully charged, if you still have surplus PV output then you can't store it.

That's where lithium has a major advantage, no need to worry about getting full or equalisation charges. The lithium will even last longer if never fully charged.

Battery banks in this setup is a very different use case to off grid. Off grid focuses on lifespan and keeping em fully charged. Powerwalls its all about cost per kWh stored, so it may make more sense to work the batteries hard. For many lead batts you get the same lifetime kWh regardless of 10% DOD or 90% DOD.



Title: Re: My PowerVault - small milestone
Post by: sam_cat on September 22, 2017, 09:06:02 AM
Tiff, what does SG mean?

Specific Gravity

https://www.freeasestudyguides.com/battery-specific-gravity-test.html



Title: Re: My PowerVault - small milestone
Post by: brackwell on September 22, 2017, 09:10:35 AM
I am having issues with domestic batts and i have come to the conclusion that they can only work if we have time of use tariffs otherwise,

Once one has used the self generated leccy then it cannot be used twice obviously.  So when the load is greater than supply then batts have no function. This naturally occurs in winter but can occur at other times if you increase the loads.
So if all one is doing is charging a batt instead of supplying one of these loads then nothing is achieved in fact worse with the batt losses.

So if we have enough load there is nothing for batts to do and so we need to use the loads sequentially and have enough of them.

The cost of the batts installed and replaced every x yrs make it very questionable.

The losses of the batts 20% ?  means that one is no worse off energy wise than if they had not bothered to capture that 20%  

Due to charge and discharge rates of the batts means that significant amounts of leccy must get exported to the grid and high demand loads cannot be supplied without the grid.

This is like off grid living whilst connected to the grid and that does not work either in my opinion.

I just dont get it.

Ken


Title: Re: My PowerVault - small milestone
Post by: RIT on September 22, 2017, 05:43:57 PM
I am having issues with domestic batts and i have come to the conclusion that they can only work if we have time of use tariffs otherwise,

Once one has used the self generated leccy then it cannot be used twice obviously.  So when the load is greater than supply then batts have no function. This naturally occurs in winter but can occur at other times if you increase the loads.
So if all one is doing is charging a batt instead of supplying one of these loads then nothing is achieved in fact worse with the batt losses.

So if we have enough load there is nothing for batts to do and so we need to use the loads sequentially and have enough of them.

The cost of the batts installed and replaced every x yrs make it very questionable.

The losses of the batts 20% ?  means that one is no worse off energy wise than if they had not bothered to capture that 20%  

Due to charge and discharge rates of the batts means that significant amounts of leccy must get exported to the grid and high demand loads cannot be supplied without the grid.

This is like off grid living whilst connected to the grid and that does not work either in my opinion.

I just dont get it.

Ken

A future possible question as and when time of use tariffs become mainstream is going to be why install the PV. In all likelihood, things like the PowerWall will drop quite a bit over the next few years and if we see time of use tariffs with over night rates down at 4p per kWh it may make more sense to just install a battery that charges itself up overnight and discharges during the high cost hours.

If FiTs ever gets withdrawn there maybe little value in installing any PV+battery solution.


Title: Re: My PowerVault - small milestone
Post by: dan_b on December 09, 2017, 02:11:23 PM
Today marks exactly a year since my PowerVault experiment began.
In those 12 months, it's discharged 867kWh back into my house.
Best month was June, where I did 103.94kWh
Worst month was January, where it did just 30kWh.

So far it's been charged purely by spare SolarPV, which is obviously biased to the sunny months where I'm still generating more than I can use in the house or in the battery. In the darker months, there's often barely been enough SolarPV to cover house demand let alone charge the battery (last December it went 5 days with 0 discharge), and those of course are the months where my demand is going to be highest due to long dark nights.

So, I've decided to try switching to an Economy7-type tariff in order to re-charge the battery at night on low-rate juice and feed that back into the house during the daytime to see if that makes any difference to my electricity bills.  It will make the battery work harder during the winter months at least.

The one I'm going with is with Tonik Energy - they're running a trial with people with batteries to test smart meters and time-of-use tariffs, but to start with it's just a straightforward E7-type package.

Let's see how it goes!


Title: Re: My PowerVault - small milestone
Post by: morrisok on January 11, 2018, 01:17:29 PM
Hi Dan,

I would do the maths before switching to Economy 7.  With a 4KW battery unless you are a very low use house you will probably pay more during the day than you will save with the 4KW you buy cheaply over night.  If you had a 10KW or 20KW system I imagine it would make a lot more economic sense to be on Economy 7.


Title: Re: My PowerVault - small milestone
Post by: linesrg on January 11, 2018, 04:39:05 PM
dan_b,

I've just run my figures through Tonik and they are, at best, £113 a year more expensive than Bulb (who I'm currently with).

At 35% night time usage Economy 7 still makes sense for us but whenever I do comparisons I still run a check on quotes with and without Economy 7.

It will be interesting to hear how you go with the smart meter and TOU tariffs.

Regards

Richard


Title: Re: My PowerVault - small milestone
Post by: marshman on January 11, 2018, 05:39:48 PM

At 35% night time usage Economy 7 still makes sense for us but whenever I do comparisons I still run a check on quotes with and without Economy 7.


Agree with Richard there. You need to get quotes for both with and without E7. The comparison sites will not do it for you. I found this out a couple of years ago when I did a search on several sites , ticking the E7 box. Then did another without E7.  Without E7 it was about 10% cheaper.  This year it is the other way round as I have changed our usage pattern.

Roger


Title: Re: My PowerVault - small milestone
Post by: dan_b on January 11, 2018, 10:30:00 PM
Ok well I've done it now anyway - got my smart meters fitted 2 days ago and they've put me on their trial tariff which is the following

daytime - 14.4p /kWh
Midnight - 7am - 8.8p /kWh

So last night for the first time, the battery charged up overnight from the grid giving me a full battery at 7am this morning.  Combination of battery discharge and a tiny tiny bit of solar generation around noon meant I didn't import anything until 4.25pm.

I also ran the dishwasher at 1am last night rather than during the day, and will run the washing machine tonight at 1am as well.

At this time of year my solar production is really poor anyway (today was just 401Wh, the day before was 122Wh!) so the battery would be going days without getting any charge at all - so that's kind of money wasted as far as that's concerned.  I thought it was worth trying this as at least I'll get more use from the PowerVault if nothing else!

I'm happy to still be treating this as all as a bit of an experiment.  Year 1 was just to see what the battery did and the impact it had with the solarPV in place- which was 865kWh of battery discharge (ie avoided import), and a drop in the work the ImmerSUN does by about 300kWh  (in 2017 the ImmerSUN took 369kWh vs 630kWh in 2016).

So year two is to see if I can make the battery work a bit harder for me - particularly in the months of Jan-Mar, and Oct-Dec where battery diversion was low (e.g. Jan 2016 was just 30kWh, so 1kWh/day average, vs June 2016 which was 103kWh, 3.3kWh average).

I imagine what I might have to do is reduce or stop the E7 charging from between June-Sept as in those months I'll be generating, and therefore storing, plenty of solarPV, so no point paying to import and fill up the battery first!

Let's find out though  :angel:






Title: Re: My PowerVault - small milestone
Post by: TheFairway on January 12, 2018, 09:24:09 AM
Whats the standing charge on that tarrif?

I almost went for a Smart meter recently but as it was SMET 1 I declined. Apparently SMET 2 meters should be available latter part of this year. I was only after them to fit an isolation switch which would have been free if I had Smart meter fitted at the time. As im not paying for the isolation switch anyway, it wasn't a big thing to sway me.

My thinking is whats the point of a Smart meter now if its not so smart if/when I change supplier.

My supplier (Octopus Energy) said that there was no penalty for taking the "smart" meter but they do plan on introducing various tarrifs like Electric Car friendly ones - not sure how different that would be to E7/10.

For anyone in the know, is there an automated way of knowing what Tarrif a "smart" meter is on? ie does it publicise its tarrif on network - even better, can you know what the up coming tarrifs are? Im not talking about looking it up on a website, im talking about automated triggering devices to charge/switch on/off etc based on the tarrif.


Title: Re: My PowerVault - small milestone
Post by: Sprinter on February 09, 2018, 02:51:55 PM
Just read this thread as i have been looking at batteries again recently, I found a Growatt SP3000 from a UK supplied with 9.7Kwh of storage for £3750 (assumed plus vat to £4500) plus delivery, we have also had a local firm knocking on my door for a while asking me if i am ready for batteries yet, to which i recently said yes get me a quote for the Growatt SP3000 with the 9.7 Kwh pack, turns out the initial price was £5750 fully installed, so that's £1250 for half a days work to install it, rip off.

Anyway, recently i also got a quote from PowerVault for their system, 6Kwh @ £5850, not bad i thought but still a little more than i want to pay, then a stroke of luck, and email from PowerVault telling me about a joint part funded scheme where they are supplying 4Kwh systems,  using either:
1, First Life (brand new) for £2899 (10 year warranty)
2, Second Life (Ex Renault) for £1899 (5 year warranty)

these are very tempting costs (installed), after reading this thread (in full) i am going to try to decide over the weekend if i am going to go for a Growatt system and install it myself, or one of the PowerVault systems.

Just in case anyone else is interested in the trail the details are on their web site, but you need to live in London or Cornwall and have it paid for and installed before the end of March.

After reading this thread and Dan's additional use of the batteries from overnight charging in the winter i think the Powervault is coming out on top, it also has an emergency socket that will run in a power cut which may well save hundreads of quids worth of tropical fish and the freezers if necessary).



Title: Re: My PowerVault - small milestone
Post by: RIT on February 09, 2018, 06:23:09 PM
The project offering discounted batteries can be found here

     https://peteproject.com/

They are also offering to replace hot water tanks with ones that can be monitored over the internet. I'm not that sure why, but if you need to replace your tank due to age it would be worth dropping them a line.


Title: Re: My PowerVault - small milestone
Post by: Sprinter on February 09, 2018, 09:01:47 PM
I also asked them if i could upgrade the 4.4kw scheme related device to a 6kwh one, the responce was yes btonly the first life battery option, at just over 1k extra.

Think i will probably go with that option


Title: Re: My PowerVault - small milestone
Post by: Iain on May 21, 2018, 11:08:00 PM
Hi
From this thread I looked into the PETE project. The outcome was a 4 Kw Powervault, with  LiFePO4 Batteries fitted last Thursday. Seems to be working great so far.
I have only imported 3kWh since last Thursday
Graph from yesterday
Iain


Title: Re: My PowerVault - small milestone
Post by: dan_b on May 22, 2018, 07:20:44 AM
Aah welcome to the PowerVault Club!


Title: Re: My PowerVault - small milestone
Post by: linesrg on May 22, 2018, 07:30:28 AM
Good Morning All,

Any chance some organisation could run a project in Aberdeenshire???????

Regards

Richard


Title: Re: My PowerVault - small milestone
Post by: Sprinter on May 22, 2018, 11:07:06 AM
My PowerVault is working great, my import has reduced by roughly 50% and its just sitting in the background doing its thing.

In fact i have just arranged the expansion to 6 kWh which should be installed in the first week in June, very happy, its pushing about 40 kWh per week back into the house, we have a high base load with the fish tanks Etc meaning it only gets us to 3am before it runs out, and hence the expansion to see if that will get up to sun up.

80% direct use though, got to be happy with that.

(https://preview.ibb.co/c6YHvo/Capture.jpg) (https://ibb.co/bCXXT8)
(https://preview.ibb.co/iJd6o8/Capture1.jpg) (https://ibb.co/nHqxvo)



Title: Re: My PowerVault - small milestone
Post by: dan_b on May 22, 2018, 11:19:28 AM
So do we have 3x PowerVaulters here now then? That's pretty cool.  Mine's working well too - am currently having fun trying to predict whether and how much to use the E7 charging overnight based on weather forecasts and how much I think I'm going to be using during the day!

My only grumble is the data available on the monitoring portal, it's not quite at the SolarEdge/Tesla PowerWall-level of ease of use, doesn't integrate with my SolarEdge portal and with my ImmerSUN having no monitoring at all it's rather difficult to keep a really good overview of what it's all doing.


Title: Re: My PowerVault - small milestone
Post by: Iain on July 04, 2018, 04:26:18 PM
Hi

My first full month with the Powervault.

These are just rough calculations.

My average daily power use is 8 kWh / day

With solar PV my import reduces to approx 5 kWh / day

With the Solar and Powervault my daily Import for the last month has been 1.2 kWh /day

The readings on the portal don't really match up with anything in reality so these readings have been worked out from my house meters.

From Powervault I get these readings


Quote
Period Monitored 2018-06-01 to 2018-07-01
Energy Imported           19.89 kWh
Energy Exported           125.18 kWh
Energy Charge AC       159.81 kWh
Energy Discharge AC   55.23 kWh


However my own meters say:-
Import 45kWh
Export 132 kWh

These tie in with my PV inverter and have read correctly so far

However the unit works a treat and am very happy with it. The monitoring could be better.
I decided on the older model but with 4 Kwh battery
It gives me the emergency outlet which supplies my important stuff during a power cut. Tested and works already. Only house in the street with power for the day!

Iain


Title: Re: My PowerVault - small milestone
Post by: dc on July 05, 2018, 08:35:41 AM
I joined the Powervault club yesterday, 4kW system.


Title: Re: My PowerVault - small milestone
Post by: Sprinter on July 05, 2018, 09:44:41 AM
welcome aboard, that's five i think we have now :)

As for the Power vault reporting its inaccurate at best, why the company takes statistics daily and then cannot add them up i don't know.

I consider ourselves to be early adopters, and are generally as much interested in the technology as the savings, so i find it strange that the company provides us with such poor reporting for our systems, I would have thought that would be one of the things that they would have sorted out so the rest of us can evangelize effectively for them. My unit number is 392 so that's definitely early adopter status as far as i am concerned (though it would be interesting to know what unit number they are up to now).

I wrote to them earlier in the week as i noticed how poor thier reporting was, the historic data changes monthly, at one point i had part reports for March which was the month i had it installed, but now the first report i have is for April, and the April figure changed at some point in June. Here is the response i had back, and i appreciate that they are updating thier portal to eliminate this, but im surprised that in this day and age they don't have the reporting locked down already.

Quote
The graphs that are generated in the historical data section of the Portal unfortunately have some inherent issues and produce fairly inaccurate figures. This is why you are seeing the discrepancy in data from each month's readings.

Whilst we are very aware of this issue and are working on fixing it, we are also unable to give a timescale for completion. This is partly because we are also developing an entirely new and much improved Portal which will be a great deal easier to use and give users access to the information they need.

I still think the system is great by the way, and is definitely cutting my electricity import and export significantly but just be aware that any reports you pull off the portal will be close to the truth I.E. in the ball park, but not an exact reflection of what the device is doing.


Title: Re: My PowerVault - small milestone
Post by: Iain on July 05, 2018, 10:21:18 AM
Hi

The readings from the portal are very inaccurate.
For a while the Charging/ Discharging was reading as Watts and also was a factor of 100 out.
As an example of the discrepancies:-
From the Portal.

Energy Imported        97 kWh
Energy Exported        135 kWh
Energy Charge AC      201 kWh
Energy Discharge AC  194 kWh

From Powervault via email

Quote
Period Monitored 2018-06-01 to 2018-07-01
Energy Imported           19.89 kWh
Energy Exported           125.18 kWh
Energy Charge AC       159.81 kWh
Energy Discharge AC   55.23 kWh

My Readings

Energy imported  45 kWh
Energy Exported  132 kWh

But

As you say the unit "does what it says on the box" and am very happy with it
My Unit is No 1012
They said they would upgrade me to the newer unit free of charge, however the new unit does not have the emergency back up supply. I believe it also charges and discharges at a higher rate.
I wanted the Emergency socket. I also thought the lower charge and discharge rates might help the batteries last longer, (rightly or wrongly??)
I also have a 2kW PV system so I thought the older unit suited my smaller system better. Not sure if my reasoning is/was correct, but all seems to work well.


Iain


Title: Re: My PowerVault - small milestone
Post by: dan_b on July 05, 2018, 10:29:59 AM
The incorrect unit factor has been fixed on my portal in the last week or so - it was like that since the beginning, I had learned to ignore it and correct it in my head.
I thought the actual data on the daily figures were relatively accurate in terms of energy saved per day - you're right though the data from the "history" part of the portal is dubious. I flagged this to them a year ago as there were clear discrepancies, seems there still are.
My unit is number 215 and I was an early adopter - good to see that they're getting other customers :)


Title: Re: My PowerVault - small milestone
Post by: Sprinter on July 05, 2018, 11:33:00 AM
I was not given the option of the new system as an upgrade, but like yourself i would not have taken it (unless it allowed me to stack even more storage batteries), the reason being is that i also wanted the emergency outlet in order to maintain my tropical fish setup in the event of a grid outage.

I was not trying to knock the system, just make people aware of the historic data issue that i am assured will be fixed soon(ish).

A great system, time to start saving for a new heating system next, it never ends :)


Title: Re: My PowerVault - small milestone
Post by: cricha on July 06, 2018, 07:31:27 AM
I've had a 4kw lead acid powervault since December 2017.
I'm interested in how accurate the percentage charge is. I notice when the charge is said to be 100% it goes on charging at a slower rate.
Reading the soecification it says the actual caoacity of the batteries is I think 8 kw but the useable caoacity is 4kw.
So I am wondering if it is actually possible to use more than 4kw.


Title: Re: My PowerVault - small milestone
Post by: dan_b on July 06, 2018, 10:15:12 AM
Welcome to the forum.

The lead acid battery pack in the PowerVault is something like 8kWh but it's set to a depth of discharge of about 50% capacity - hence 4kWh - this is to try and prolong battery life by not fully discharging it every time.
What you should see is that the closer it gets back to 100% capacity the slower it will charge, until it maintains a sort of "trickle" charge.

What I have seen with my battery is that it's quite possible to get more than 4kWh out of it during the day if you use your white goods in the morning, drain some of the battery, and then it can re-charge again in the afternoon. I've actually seen 7kWh of discharge in one day in May this year which must have been a long sunny day and I probably did a lot of loads of washing!



Title: Re: My PowerVault - small milestone
Post by: cricha on July 07, 2018, 11:15:16 AM
Is the figure that powevault produces for energy saved the total energy from the battery during 24 hours. It varies so much that I wonder how accurate it is. I have seen over 8kw on one occasion.

I am part of the Tonik trial which involves using off peak electricity to charge the battery when there is little solar energy available. Setting how long to charge for is a bit hit and miss. The result has been a karger total energy consumption but as about 65% of energy from the grid is off peak the cost is definitely less.

If I have understood correctly what Tonik plan it us to charge a varying amount according to the wholesale price and to control the battery so it discharges when the price is high.


Title: Re: My PowerVault - small milestone
Post by: Iain on November 26, 2018, 03:52:29 PM
Hi
Small update on the Powervault.
I have had a problem on 3 occasions.
Each time it is the day after a poor solar day with no or only a small charge.
On the 3 occasions when the PV starts producing in the morning the Powervault has not started charging. A reset will start it working again.
Happened yesterday and today.
Waiting for a diagnosis from Powervault.
One of the comments was the battery has stopped communicating. Not sure if that means new batteries or some software fix.
Not a good start!
Iain


Title: Re: My PowerVault - small milestone
Post by: Iain on January 15, 2019, 02:00:39 PM
Hi
A follow on from the last post.
It seems one of my batteries has failed.
Just had both replaced today.
I think on poor solar days the Powervault battery sits for a long time on 0% or very low. I wonder if this has caused it?

I requested they add another regime to the charging profile.
They have now added "Winter Charging"
This allows the unit to "Charge Only" for the week and over the weekend switches to normal.
It is a compromise to allow the batteries to charge up fully before discharging/charging as normal.
It is possible to set up your own regime using the "Tide" controller. However every time you switch the unit back to "Economy 7/Normal" The tide profile reverts to its default and has to be set up again next time.
With the "Winter Charging" it is simple to switch it on or off as required. If I have a few cloudy days I just go to winter charging then just switch back when it becomes sunny again. Mainly for the winter period hense the name!
Glad the batteries have a 10 year warranty!
Iain


Title: Re: My PowerVault - small milestone
Post by: Tiff on January 15, 2019, 04:06:05 PM

Any significance of it being cell 9 (I assume the last in the series) that is so far out?

Does also make you wonder if bottom balancing would be better than top balancing.

Also very early in its life for a failure. Do you think they will give any feedback on the cause? I expect they may not want to share the details.


Title: Re: My PowerVault - small milestone
Post by: Iain on January 15, 2019, 05:04:16 PM
Hi

Quote
Any significance of it being cell 9 (I assume the last in the series) that is so far out?

Not sure but No 5 is going as well.

If I get any feed back I will pass it on.
Not sure if it is top balancing. I did make a comment that it would be nice to limit the lower cut off so that there was always some capacity left for the emergency supply outlet. The reply was that it needs to go down to zero so I did wonder if they bottom balance. So I am not sure really.
These batteries are the "new" ones with the 10 year warranty and not the second life ones with a 5 year warranty, so I hope this is a one off. It is good though that they can monitor each cell remotely for diagnostics. I think it is a manual check as it was me that prompted them that there was a possible problem. They then checked and came back with those graphs.

Iain


Title: Re: My PowerVault - small milestone
Post by: nowty on January 15, 2019, 09:44:19 PM
Thatís pretty shocking for new batteries. sh*tfan:

My bodged system with mixed second hand growatt lithium batteries has been running for a whole season now and five cells are within 0.01v, one is within 0.1v and one is within 0.14v.
And thatís with no balancing circuitry whatsoever. :crossed

(https://i.postimg.cc/1XtmbqzD/Growatt-Battery-013.jpg) (https://postimages.org/)