Navitron Renewable Energy and Sustainability Forum

Energy/Electricity Storage and Use/Grid Connection => Off-Grid, Batteries & Inverters => Topic started by: nowty on July 10, 2012, 10:29:03 PM



Title: My Off Grid System Is Now Complete
Post by: nowty on July 10, 2012, 10:29:03 PM
(http://s8.postimage.org/4z9dmfy3l/Off_Grid_Batteries.jpg) (http://postimage.org/image/4z9dmfy3l/)

(http://s8.postimage.org/oidyvswv5/Off_Grid_Kitchen_Roof_Panels.jpg) (http://postimage.org/image/oidyvswv5/)

(http://s8.postimage.org/sssmre1y9/Off_Grid_Lower_Front_Roof_Panels.jpg) (http://postimage.org/image/sssmre1y9/)

(http://s8.postimage.org/mt4vnqh5t/Off_Grid_Shed_Roof_Panels.jpg) (http://postimage.org/image/mt4vnqh5t/)

(http://s8.postimage.org/lfd8sfhwh/Off_Grid_Sunny_Island_and_Boy_Inverters.jpg) (http://postimage.org/image/lfd8sfhwh/)

(http://s8.postimage.org/i9sn27za9/Off_Grid_Inverters.jpg) (http://postimage.org/image/i9sn27za9/)

(http://s8.postimage.org/cznoaxf1d/On_Off_Grid_Auto_Load_Switching.jpg) (http://postimage.org/image/cznoaxf1d/)

(http://s9.postimage.org/rteorjx5n/Sunny_Island_Control.jpg) (http://postimage.org/image/rteorjx5n/)

Some of you may have seen a few of my pics on another thread over the past few months, but as I have now practically finished my off grid system I thought folks might want to see pics of the whole system.

My idea started off to buy a few smallish leisure batteries, a couple of panels on my lower front roof and a very small inverter to run my internet 24/7. BUT, after much reading of these threads, buying some cheap gear off fleebay, getting a bit carried away, etc, etc, it has evolved into quite a system.

All DIY (no FITs facepalm), but I do also have a 4kw grid tie system getting the full rate so I am content overall with the green incentive thing and I have almost doubled my green PV capacity without any DNO issues. Yes I know its not financially viable but nor is paying high green elecy tariffs but at least I know mine is 100% green.  :cross

Its based on the SMA Sunny Island and the PV is fed into Sunny Boys all AC coupled to it. The Sunny Boys are standard grid tie inverters reconfigured into off grid mode with auto power limiting based on frequency shift from Sunny Island unit when batteries are nearly full and loads are low.

It now runs my big 55 TV, small kitchen TV, main PC, laptop, all internet and network gear, Sky box, telephone base station and above 75% battery at night also my kitchen heated floor, two fridges and central heating boiler.

It started working about 2 months ago and has evolved in operation as I have added more PV, inverters and loads. Even with the rubbish weather we have been having, the batteries have not gone lower than 65% and its now saving me an average of 6 units per day. It is fully automated with auto switch over of loads on/off grid via relays which switch based upon time of day and state of charge of the battery.


Title: Re: My Off Grid System Is Now Complete
Post by: Cornish Dragon on July 10, 2012, 11:03:31 PM
Hi Nowty.....
Really excellent set up......
Well done you are going the way
i wish to be in the future...... :genuflect
Please keep us posted as things progress...
CU
CD


Title: Re: My Off Grid System Is Now Complete
Post by: billi on July 11, 2012, 09:06:18 AM
great

Quote
It is fully automated with auto switch over of loads on/off grid via relays which switch based upon time of day and state of charge of the battery.


Can you explain this part a bit more in detail ?

Thank you

Billi


Title: Re: My Off Grid System Is Now Complete
Post by: nowty on July 11, 2012, 08:35:49 PM
The SI has 2 internal multi function relays which can be programmed to switch on by a variety of events and I am using them for the state of charge (SOC) values. To avoid confusion SOC of 100% is full and 0% is empty. Because these internal relays are low power I have them triggering some more powerful external relays which are rated at making and breaking much higher loads and I also needed an extra external relay to add a switch based on time of day. Lets call the internal relay Int1 and the external relays Ext1 and Ext2.

For the load switching I have initially set Int1 at 75% to 90% SOC, i.e. when the battery passes over 90% full the relay is on, when the battery drops below 75% full the relay is off. Ext1 has a grid connection from my main consumer unit to the NC contacts and an AC off grid connection from the SI to the NO contacts. The loads of my heated floor (1.1kw), fridges (0.1kw), central heating boiler (electronics and pump, 0.1kw) are connected to the C common contacts. Therefore the default setting is for grid power for these loads. I utilise another relay Ext2 which is triggered by an external timer so these loads are only powered by the batteries if both the battery condition is good and its also not daytime. This is so my main 4kw grid tie system can still normally power these loads during the day.

I have 3 other low power individual circuits which comprise extension leads running under my floor. These are currently manually switchable between grid and off grid. As winter approaches I will switch some of these back to the grid for the deep winter darkness period.

1)   Sky box, broadband modem, router, network switch, HDMI repeater and network storage unit, telephone base station (0.1kw) and runs 24/7.
2)   Big 55 TV (0.1kw), runs mainly in the evening.
3)   Main PC (0.1kw), runs mainly in the evening.

In operation once the batteries are full the first 25% of the battery will have a heavy load and if there was no sun at all the first 25% would be used up in about 1 day. The second 25% of the battery would last a further 2 days if there was no sun because the load has been automatically reduced. But there is always some sun and even on really bad summer days I believe this 3 days will stretch out to 4 or 5 days. Now we are down at 50%, but are still a few more days away from the disastrous less than 20% level.


Title: Re: My Off Grid System Is Now Complete
Post by: clivejo on July 11, 2012, 09:25:07 PM
Looking good!


Title: Re: My Off Grid System Is Now Complete
Post by: nowty on December 23, 2012, 01:57:46 PM
Its now after the shortest day of the year so I thought I would give an update on my system. I was expecting to be shutting the system down or leaving the batteries on float in Dec/Jan, but the system is still working well and is regularly adding 3 to 4 units each day if it is reasonably sunny. To preserve the battery level at this time of year I have limited the depth of battery discharge to only 20%, i.e. it switches back to the grid when battery drops to 80% full and it needs to charge to over 90% full in order to be used the following evening. On standby the system needs about 0.5 units per day to keep the battery level constant and so far it almost always gets at least that much so the batteries dont deplete day after day.

I have estimated that with the extra 3.4kw of off grid PV capacity I have installed and the increased self use of electricity via the batteries, I have increased my annual savings of electricity import from 100 to 400 compared to simply having a standard 4kw grid tie system. With both my grid tie and off grid systems I estimate I will have reduced my electricity import per annum from 6,500 units down to around 2,500 units. Of the remaining 2,500 units, 60% is during Nov to Feb and I think only a wind turbine could make any further impact on that.

Changes I have made since the summer,

1) Replaced the GTI inverters from 2 x SB1200s to 1 x SB4000TL. The advantages are,
a)   Increased efficiency.
b)   I can set a single overall power limit on the SB so this matches the max charging capacity of the Sunny Island and thus lower the risk of overload in mid summer.
c)   I can use SMA Optitrac shade management which has made a big difference.
d)   I made as much money selling my old inverters on fleebay than it cost to buy the new one !

2) I wired in a more permanent second consumer unit to power my off grid circuits and made the system failsafe so if the off grid fails or I manually switch it off for maintenance, the off grid circuits automatically switch back to the grid via a heavy duty power relay with no outage time. This heavy duty relay also replaces a smaller relay which suffered from stuck on contacts on the odd occasion. Pics below.

3) I added my lighting circuits to it, but have taken my heated floor circuit off it. My reasoning here was to have a more lower constant load rather than a few short high peak load.

4) Added some ventilation to the sealed front panel of the Sunny Island which kept filling up with water through condensation which got so bad it shorted out the on/off switch on the front panel and simulated a manual shutdown. This was a most baffling problem which took me a month to diagnose.

(http://s2.postimage.org/wnzxexl4l/Off_Grid_Consumer_Unit.jpg) (http://postimage.org/image/wnzxexl4l/)

(http://s8.postimage.org/e10s8h6mp/ON_OFF_Grid_Auto_Switch.jpg) (http://postimage.org/image/e10s8h6mp/)



Title: Re: My Off Grid System Is Now Complete
Post by: camillitech on December 23, 2012, 04:44:08 PM
Nice work Nowty  :genuflect may the days get longer and longer  8)


Title: Re: My Off Grid System Is Now Complete
Post by: biff on January 08, 2013, 08:39:30 PM
Nowty,
        I have no idea how I missed your thread but it is an exellent setup.It has the hallmarks of a classic little system that could be adapted for use by thousands.When you take into consideration the feeling of independance and the massive relaibility factor then the finance does not really mean that much and it does payback in time.Nice job and like Paul says,May the days get longer and longer  :genuflect
                                                                            Biff


Title: Re: My Off Grid System Is Now Complete
Post by: Outtasight on January 18, 2013, 03:39:12 PM
Bodgetastic! (meant in the nicest way possible).

I haven't yet gotten round to automated circuit switching (preferring to keep separate circuits that I just then swap the loads between manually by selecting a solar or grid 13A socket in the kitchen, etc.).

As you say, it's only on continuous bad runs of black weather that the system bottoms out and you have to run round swapping circuits.

Anyway, congrats on the great work you've done so far and keep at it!


Title: Re: My Off Grid System Is Now Complete
Post by: nowty on January 18, 2013, 11:44:47 PM
Having just looked at your website I feel we are on the same wavelength.
Near 30 years ago I did an engineering apprenticeship in the Nuclear industry and gained the proud nickname of "The Bodger" !  sh*tfan:

Interesting that you went for lithium batteries as I note that even though yours are less than half my battery capacity, your useable capacity is about the same as you can use more of the capacity and leave them semi charged without worry.


Title: Re: My Off Grid System Is Now Complete
Post by: nowty on June 22, 2013, 11:01:47 PM
My Sunny Island system off grid system with forklift batteries has now been running for about a year so I thought I would share some stats on it. The Sunny Boy / Sunny Island logs (+ some simple maths) have shown,

2316 kWh's have been generated.

1709 kWhs has been used to charge the batteries and the batteries have supplied 1524 kWhs which imply a battery efficiency of 89% which I find quite impressive. It will be interesting to see how this efficiency drops in future years as the batteries age and inevitably sulphate.

The system has allowed me to self use around 2000 kWhs and around 300 saving on my elecy bill and saved 1.2 tonnes of CO2. This is in addition to the circa 150 elecy savings and 2000 FITs income I get from my main grid tie system.

The batteries have used either 10 or 15 litres (cannot remember) of de-ionised top up water.

Percentage of total running time at Battery SOC levels
SOC            % of Time
100%          28%
90%            42%
80%            24%
70%            4%
>60%          0%

The SI gives also gives a battery State of Health (SOH) (%) indicator which is the current measured battery capacity expressed as a percentage of the original capacity of the batteries as manually inputted on commissioning. My current SOH is 96% after dropping to 94% over the Winter period. Interestingly the highest it has ever been is 96% when I first commissioned the system. I think this is because I slightly overestimated the capacity @ C10 discharge rates. The batteries were sold to me as 1000Ah @ C20. Using the SI adjustment table I re-calculated them to be 917Ah @ C10, but I have since seen from the battery data sheets that the capacity should have been slightly lower @ C10. So looks like the batteries are still like new.

I am toying with adding some more panels as a facade on my ESE facing rear fence. Not strictly legal without planning permission but they would hardly be noticed by anyone. This would not add much overall capacity but it would help in early spring and late autumn when the sun is low. I have found that you need more charging power in the morning when the batteries can take a higher bulk charge to give the batteries more chance of completing the slower absorption charge later in the day when excess power is wasted by the Sunny Boy severely power limiting.


Title: Re: My Off Grid System Is Now Complete
Post by: billi on June 22, 2013, 11:16:07 PM
Quote
Percentage of total running time at Battery SOC levels
SOC            % of Time
100%          28%
90%            42%
80%            24%
70%            4%
>60%          0%

thanks for sharing this info

i wonder , what is the total lifespan of a good lead acid battery , ok mine is 10 years old and still   doing ok  , similar cycles like you seen over the year



Title: Re: My Off Grid System Is Now Complete
Post by: nowty on June 22, 2013, 11:25:11 PM
I would add that the batteries have actually been lower than 60% on a few occasions but the system must not register it if its less than 1% of the time. Fifty something % on maybe five occasions and forty something % on two or three occasions and then only for a very short time period.

When I set the system up I told myself that if the batteries only last 5 years I would be disappointed and my experiment would be a failure.
If the batteries lasted 7 or 8 years I would be satisfied.
If the batteries lasted 10 years or more I would be over the moon, so here's hoping.


Title: Re: My Off Grid System Is Now Complete
Post by: camillitech on June 23, 2013, 06:19:47 AM
Excellent and interesting stuff Nowty,

my FLA's are exactly eight years 'out the box' and still doing OK, certainly nothing like the new performance but still perfectly adequate. I reckon 25lts PA and mine are certainly cycled deeper than yours through the dry months, as I tend to switch off 'autostart' if the forecast is for wind. Though having just fitted 940w of these http://www.navitron.org.uk/product_detail.php?proID=664&catID=135 on the roof I'm just waiting for the wind and rain to stop and the sun to come out  8)

http://lifeattheendoftheroad.wordpress.com/2013/06/14/all-i-need-now-are-the-panels/

(http://lifeattheendoftheroad.files.wordpress.com/2013/06/010_thumb3.jpg?w=716&h=538)

Yes I know my battery top is a disgrace but that's a plastic sheet and conveyor belt ontop.


Title: Re: My Off Grid System Is Now Complete
Post by: biff on June 23, 2013, 02:46:17 PM
Hi Paul,
         Good choice of panels.You will be wishing you had had the PV installed years ago.The fuel savings is massive.Cyril will now be taking a back seat and I can guarantee that your oil filled rads will be getting very hot indeed.
   The pv really is the business,
                                Biff
   


Title: Re: My Off Grid System Is Now Complete
Post by: Gadget50 on August 22, 2014, 10:10:14 AM
Very nice system i am interested in fitting a system similar to this myself but dont know where to start.
I have a grid connected system with a fronius inverter looking @ a 24 volt 1000 amp hour system and use about 5kwh per night so id use the batteries to 80% full charge.
thats as far as i got.
Help or advice will be very welcomed. confused how to go further. wackoold     


Title: Re: My Off Grid System Is Now Complete
Post by: nowty on August 29, 2014, 09:16:41 PM
To Gadget50

All depends how much you want to spend and how technical / confident you are yourself.

Example, I am an electrical engineer so I just love installing stuff and tinkering with it as an experiment and not care too much about whether its ultimately financial viable or not. However so far my demonstrated savings show that even without FITs the life cycle costs is very close to cost neutral and Id rather have solar panel / inverter manufactures have my cash than the fossil fuel hungry robbin elecy grid companies.

From April to Sept my elecy is now 90% solar, day and NIGHT !

Separate Off Grid System (like mine)
Have a system like mine where you keep your current grid tie and add a separate off grid system (additional PV, island inverter and batteries) and switch your circuits between grid during the day and off grid overnight.

Advantages : No DNO issues, no FIT provider issues, significant additional extra capacity, grid independence. Can claim extra FITs if additional PV is added via MCS installer.

Disadvantages : Expensive, complicated re-wiring of house circuits.


Hybrid System
You add batteries to be charged with excess PV energy from existing grid tie system and drip feed back at night with a small grid tie inverter to match your background usage.

Advantages : Cheaper, smaller batteries, modest increase in self usage, no complicated house circuit re-wiring.

Disadvantages : DNO issues if connecting another grid tie inverter, FIT provider issues if seen as modification of exiting system, no grid independence.



Title: Re: My Off Grid System Is Now Complete
Post by: phoooby on August 29, 2014, 10:34:24 PM
Quote
Can claim extra FITs if additional PV is added via MCS installer.

So if I got a bog standard 4kw tied system installed and at the same time got another 4kw system installed on an "off grid" basis supplying a few circuits (lights and single feeds to TV's and computers etc) , I could get FITs for an 8kw system ?.


Title: Re: My Off Grid System Is Now Complete
Post by: billi on August 30, 2014, 01:52:43 AM
Quote
Hybrid System
You add batteries to be charged with excess PV energy from existing grid tie system and drip feed back at night with a small grid tie inverter to match your background usage.

Advantages : Cheaper, smaller batteries, modest increase in self usage, no complicated house circuit re-wiring.

Disadvantages : DNO issues if connecting another grid tie inverter, FIT provider issues if seen as modification of exiting system, no grid independence.

... Hmm , or instead of  a small grid tie inverter,  use  for example a Studer xtender inverter , that synchronizes with the Grid and gridtied PV  and "smart boosts" the Grid (http://www.mysolarshop.co.uk/images/xtender_smartboost.jpg) , but also can act as a stand alone off grid inverter ....

or other way round , like it is done in many off the shelf AC storage systems , monitor the incoming PV production and load needed and let the Studer xtender supply additional power needed from the battery instead of the grid (http://www.smart-powershop.com/images/smartenergyplus/SmartEnergyPlusS_schema.png)


Quote
Help or advice will be very welcomed. confused how to go further. wackoold

@Gadget50

also Victron inverters (Navitron stock them ) have nice options to combine FiT harvesting PV s and battery ideas

http://www.victronenergy.com/upload/documents/Whitepaper-Self-Consumption-and-Grid-independence-with-the-Victron-Energy-Storage-Hub-EN.pdf

Quote
2.3. VE Storage Hub-3
DC electrical power generated by the solar panels i
s converted to AC by a PV inverter connected to
the AC
input
of an inverter/charger.
The power from the PV inverter is supplied to the l
oad through the inverter/charger.
In case of insufficient PV power the inverter/charg
er will supply additional power from the battery, o
r
from the grid.
In case of excess PV power the inverter/charger wil
l use the excess power to recharge the battery.
Once the battery is fully charged the PV inverter w
ill supply excess power to the grid.
If the PV inverter is fitted with an anti-islanding
device according to local regulations, an anti-
islanding device is not needed.
In contrast to the Hub-1 and Hub-2 solution the PV
inverter will shut down in case of a utility power
outage. The Hub will continue to supply the load un
til the battery is discharged.

(http://www.royal-tech.cn/images/HUB3.jpg)




Title: Re: My Off Grid System Is Now Complete
Post by: clockmanFR on August 30, 2014, 09:32:04 AM
Well said nowty.....

"However so far my demonstrated savings show that even without FITs the life cycle costs is very close to cost neutral and Id rather have solar panel / inverter manufactures have my cash than the fossil fuel hungry robbin elecy grid companies."

I agree, we here beat the normal standard day tariff from EDF, but we still use the cheap EDF night tariff.

The thing is nowty, some how we folk that do, MUST, MUST explain to the wider public at large.
So go on nowty write a book about your set up and experiences.

Here in France even the local EDF Meter reader informed my Mrs CM that generating and using your own Electricity was illegal, as you can imagine he got short thrift.
Next year we are having a couple of open days, linked to the local BIO association stuff, and the Mrs will do a 4 page A5 explanation leaflet.

Interestingly my French teacher put together an article on our project here, with full costing's, etc, "I can not understand it CM, none of the ECo/sustainability Journals/magazines in France will publish, because they say their advertisers will be upset". 

Go on nowty get writing.


Title: Re: My Off Grid System Is Now Complete
Post by: biff on August 30, 2014, 10:56:58 AM
The big grid companies must be starting to feel a tad insecure,
                                     It does stand to sense that if enough householders with PV join together and act as one voice,they will in time be able to dictate their terms to the big companies.
 It is a little side show that people would never dream off initially but with enough power being generated, It would not be very long before someone got into the driving seat and pointed out the fact.
  One of the big advantages of PV power is that it is very much trouble free and if set up properly does not require a lot to maintain. Unlike all the power stations which needs thousands of staff,the PV owners are the staff,so costs in that respect are a big fat Zero.
  So if you are a big company director and have your own personal think tank,and are a little worried about any up and coming opposition,you would automatically look at renewable energy as opposition and do your best to erect hurdles and charges and delaying tactics designed to put people off.
 The big grid companies have shareholders to answer to, They have massive overheads, Once the PV is paid for, the PV has no overheads whatsoever. So you can see at a glance that some time in the future these big grid companies are going to have to do some serious mental footwork because the power generating side of things will be out of their hands and into the hands of PV and renewable energy people. When Offpist,s and Chris75 ventures bear fruit ,which I have no doubt they will. The whole business of supplying electricity will have changed beyond recognition.
                Some of my neighbours,,home alone basic electricity needs, no lecky shower, no lecky fire,,200euros for 2 months..is very common.
  When I think of what has been achieved in Castlebiff where the excess electricity goes into tanks and then into the rads,Our savings would be well in excess of our neighbors. We use no diesel worth talking about.This is not some kind of boasting lark but rather ,I am pointing out that we can now afford to get off grid and recoup or financial outlay a lot quicker than the original 7 years we used to say.
  In fact,I would say that we could easily recoup our 3kw PV outlay in a comfortable 3 years. Our Wind turbine will take a while longer but the PV is a no brainer..
  If I were a big grid supplier,, I would be worried.
                                                           Biff
 


Title: Re: My Off Grid System Is Now Complete
Post by: nowty on November 22, 2014, 12:44:09 PM
The latest addition to my off grid system, its a solar ladder store building, not a ground mount, honest. stir:
(http://s27.postimg.org/bae70qlu7/Solar_Ladder_Store.jpg) (http://postimg.org/image/bae70qlu7/)
Also worked with a local installer to get the new panels MCS'd and FIT'd to fund future battery replacements. :crossed

Interestingly the EPC for my home has risen from an E when I bought it 6 years ago to a B. ralph:


Title: Re: My Off Grid System Is Now Complete
Post by: camillitech on November 22, 2014, 01:47:26 PM
The latest addition to my off grid system, its a solar ladder store building, not a ground mount, honest. stir:
(http://s27.postimg.org/bae70qlu7/Solar_Ladder_Store.jpg) (http://postimg.org/image/bae70qlu7/)
Also worked with a local installer to get the new panels MCS'd and FIT'd to fund future battery replacements. :crossed

Interestingly the EPC for my home has risen from an E when I bought it 6 years ago to a B. ralph:

So is that it 'complete' now Nowty  :crossed nice one.


Title: Re: My Off Grid System Is Now Complete
Post by: nowty on November 22, 2014, 03:01:12 PM
So is that it 'complete' now Nowty  :crossed nice one.


Probably as I have run out of suitable places to add more panels. facepalm
(http://s12.postimg.org/osh1hzaxl/Front_and_Back_of_House.jpg) (http://postimg.org/image/osh1hzaxl/)
And storage capacity for the excess generation. :fume


Title: Re: My Off Grid System Is Now Complete
Post by: camillitech on November 22, 2014, 03:14:40 PM
So is that it 'complete' now Nowty  :crossed nice one.


Probably as I have run out of suitable places to add more panels. facepalm
(http://s12.postimg.org/osh1hzaxl/Front_and_Back_of_House.jpg) (http://postimg.org/image/osh1hzaxl/)
And storage capacity for the excess generation. :fume


Oh, I don't know, you could probably get 500w mounted vertically under the bedroom window  :hysteria


Title: Re: My Off Grid System Is Now Complete
Post by: skyewright on December 02, 2014, 10:09:16 AM
Also worked with a local installer to get the new panels MCS'd and FIT'd to fund future battery replacements. :crossed
Did you have any additional "fun" getting an off-grid system FIT'd for a house that's on the grid?


Title: Re: My Off Grid System Is Now Complete
Post by: nowty on December 02, 2014, 07:28:43 PM
Also worked with a local installer to get the new panels MCS'd and FIT'd to fund future battery replacements. :crossed
Did you have any additional "fun" getting an off-grid system FIT'd for a house that's on the grid?

A little extra fun, my FIT provider referred the application to their "compliance dept" :onpatrol, who phoned me and asked a few questions. They said there was no problem in principle with having an offgrid system attached to a house on the grid but they did say OFGEM was getting more difficult. They just needed to be sure it truly was off grid and that I wasnt cheating by simply grid tying nearly 9kw of PV without informing the DNO.

They asked how it was set up and I sent them a block diagram, plus a few photos and the contract came back for me to sign within a couple of hours. ralph:

OffGrid Metering
(http://s23.postimg.org/h9h6fymlz/Off_Grid_Generation_Meter.jpg) (http://postimg.org/image/h9h6fymlz/)


Title: Re: My Off Grid System Is Now Complete
Post by: biff on December 02, 2014, 07:50:29 PM
Well done Nowty,
               You are on a winner. :crossed
                                         Biff