Navitron Renewable Energy and Sustainability Forum

Energy/Electricity Storage and Use/Grid Connection => Off-Grid, Batteries & Inverters => Topic started by: V on September 20, 2013, 10:23:28 PM

Title: Advice please
Post by: V on September 20, 2013, 10:23:28 PM
I am struggling to get quotes (we have one) and advice for an off-grid system. We are replacing a house which was off-grid (we've never lived there) and want to stay off-grid using PV, Batteries and a Generator. Both of us are fairly hands-on DIY and both have done things with electronics. We hope to find an installer / designer who will work with us and also teach us to make it all work.

I've put a document with our projected electricity use on my website. But in a nutshell:
  • 6 kW hour per day requirement (doesn't include lighting or water pumps.)
  • Our additional usage based on various activities like cleaning, washing machine and cheesemaking*.  On a busy day we might use as much as 11.5 kWh but with planning we could bring this down to 9kWh.
  • We have plans to reduce our electricity use, but we bought Easterdown because we want to increase my miniscule,
     *tiny production of artisan cheese into small-scale production

Website info, click here (

All help and advice very gratefully received.

Vickie (

Title: Re: Advice please
Post by: knighty on September 20, 2013, 10:40:13 PM
you should be able to find all the information you need here on this forum, and should be able to do most of the work yourself

there's a few important things to remember....

insulate the house like crazy, extra insulation now means a lot less heating for... forever

mount as much PV as possible, once it's all set up, it's problem free and provides power for free - design the house with this in mind, you need as much south facing roof area as possible, at about a 30' angle if possible

if you have to use your generator regularly, you'll come to despise it and the cost of the fuel for it

have as large of a battery bank as possible, the less you discharge it the better, if you only discharge it by 40% daily it'll last you for donkeys years... if you discharge it by 80% it'll be pretty tired after a year and probably useless after two years

have a large thermal store with a mix of immersion heaters in it, that way when your battery bank is full, you can have any extra PV generated power dumped into this thermal store... to be used as (free) heating and hot water

there's quite a lot of details to hash out (and there's other people here with a lot more experience than I)

how far along with planning are you ?
have you designed the new house ?
how far are you away from mains power ?
bit more info about the house too, how big, how many bedrooms, how many floors etc. etc.

Alan :-)

Title: Re: Advice please
Post by: biff on September 20, 2013, 11:40:10 PM
Hello V and welcome to the forum,
                               Like knighty says,insulate,insulate and insulate again.Its the best money you will ever spend and will slice your fuel bills as well as your carbon footprint.Invest in led lighting but be sure to investigate it properly,there are some rubbish buys going.Household appliances are another very important study.You can buy a 600watt Dyson vacuum cleaner will will give fantastic results.We have one now for over 5 years and it is exellent.
   You could have a seperate freezer room, no upright fridges but chest freezers instead,either converted to a fridge or set on a timer.Upright fridges are a terrible waste of energy and should be avoided.A minimum 3kw groundmount array would be a good start,If you can errect a wind turbine then do so,If you have a river or a stream then consider hydro,the aim is to have as many renewable power sources,to avoid puting all your eggs in one basket.Your main aim is to use yourgenerator as little as possible.I see that you have some electrical experience and that is a good start.My first wind/pv system was a 12volt system and far from perfect but it taught me a lot.I switched over to 120vdc because I found that I could use a lot lighter wire and it is more efficent(debatable).
  Its a learning curve V.You are not going to get it perfect firs time.You will have to tweak and study and keep and eye on how things are doing but it is all very very doable and rewarding.Navitron have good buys in PV panels and controller/inverters and are exellent people to deal with. whistle
  Write it all down,dates,prices,etcBeing off grid is very enjoyable,especially when you are running diesel free and getting free hot water.
        Good luck,        Biff

Title: Re: Advice please
Post by: V on September 21, 2013, 06:44:21 AM
Thank you so much for the prompt replies!
Planning permission applied for, but the little bit to the left will be built next month under permitted development. Highly insulated, as suggested. The planners are happy for us to live in that for a bit, (rather than a caravan) while we plan the inside of the other bit and build it. .The Cabin' as we refer to it will be made from with highly efficient SIPS clad in timber.
( (

We have our godmother staying this weekend, but I hope to ask more detailed questions by monday, please stay with me! I have been reading this forum for a few months, hoping to be self teach, but while I have a few ideas I would be grateful to have some experienced people to bounce ideas off of. Questions like, Studer vs Sunny Island? Dare I be bold and go with the Winston Lithium Iron Batteries?

Re: freezers - I've been exploring the idea of using this compressor to build some refrigeration and freezing, especially for my cheesemaking:

Title: Re: Advice please
Post by: Greenbeast on September 21, 2013, 07:27:46 AM
I love the idea of building custom refrigeration equipment but have not ventured into it myself

Title: Re: Advice please
Post by: billi on September 21, 2013, 09:00:35 AM

the "pv array calculator"  looks a bit too optimistic to me Winter

Here is another one , that gives you PV production figures ...

Is there much cooling required for the cheese in Winter ?

A question you should ask yourself is as well , when during a 24 hour day , you will need the most electricity ? Perhaps a (partial) AC coupled  PV -offgrid Inverter  idea  makes sense for direct feeding the consumers from the PV

Me , personally would go this route today , a part of the PV feeding the system via Grid tie inverter and the remaining part via charge-controller


Dare I be bold and go with the Winston Lithium Iron Batteries?
  In a Situation with a grid connection with a battery backup PV , i possibly would consider those ,  but in a off grid idea ..... i would try to use the funds to have enough PV and battery to avoid generator running hours = reduce the deep cycles of the lead battery seen over the year

Title: Re: Advice please
Post by: clockmanFR on September 21, 2013, 09:47:14 AM
Hi Vickie,

Here's are doings!

Not for profit,,,,, (

Mrs CM does the facebook and twitter stuff and is usually prompt at replies.

We dump excess generated energy into our electric underfloor heating, throughout the house and gites.

I can not emphasise enough that you should Insulate, Insulate, Insulate, and more Insulation, to get your heating energy minimal.
Here we have gone the passive House standard, (see one of my designs). And if you look at our site we insulate minimum in roof spaces to 500mm and then board out, walls are 500mm thick mostly insulation. Are old buildings?, well we build inside and keep contact with the original building fabric very minimal, but use materials that insulate, insulate, insulate.

Agreed, get your battery bank up as much as possible we have a 65kwh 1300ah at 48v, but its not enough for all our buildings so installing another 1000ah lot.

Originally we concluded that a 15kva generator would meet our needs, but to be honest as PV panels are now at a cost effective price, we are getting as much up as possible.
Eventually we will have 12kw of Wind Turbines, and 9kw of PV. A Hydro lake battery small spring source with a 2kw Hydro system.

Costs,..... last time we did costing for buying everything of the shelve was Christmas 2012, with my mate Dimitri who's building a Large Log Cabin down the road. (he's building his PV trackers in wood  facepalm) Best we could achieve for his house was 16,000 and that did not include all the labour, funny, that it was exactly the same price as an EDF connection  ::).

Best advice we can give you Vickie, please go and see folk who are off Grid and asses your needs in comparison.

As regard building, I find the English Building regs stifle Energy Saving, Yes you can go the Passive Huase building route, but its costly, as most UK builders will tell you. svengo

Your welcome to come and visit us.  

Title: Re: Advice please
Post by: Mostie on September 21, 2013, 10:23:50 AM

Re: freezers - I've been exploring the idea of using this compressor to build some refrigeration and freezing, especially for my cheesemaking:

I think that might be the compressor inside the Steca freezer

Title: Re: Advice please
Post by: biff on September 21, 2013, 11:04:55 AM
Good Morning V,
                We all wish you good luck with the planning permission and hope it all goes smoothly for you.These are life changing decisions and not to be taken lightly so every step has to be carefully considered and every effort should be made to stay on the right side of the neighbours.Be assured that you will always find one who will stick out the foot and quite often there is nothing one can do with someone like that apart from staying clear of them.
                        "Grand Design" springs to mind.My wife and I were watching Chris from London,struggling with his new house build in Taunton(I think). Chris had dreamt of buildng his house for 20 years and bought into an american water mill design which he intended to build into the side of a hill which did not even have a stream.He made life so difficult for himself by not sticking to the plan and not getting "things in writing".
    No matter what you build,forget about demonstrating your cleverness and imagination.Build plain n strong and insulated to the hilt.Keep the cleverness and good stuff descreitly hidden and concentrate on getting the best results possible. You will find that if you play it that way,little setbacks will be easily overcome and will not grow into major issues. Always build with an option to sell.The first neighbour to visit you will be extra friendly but this neighbour will also reltell everything you say and do and you will be especially lucky if they do so in glowing terms.So its best to have that slightly puzzled look. Building houses were my passion,When I was younger I liked to build silly big barns.Our present house,(My last)is one of the smallest I ever built and has a footprint of only 38ft x 27ft.It could have been a lot smaller.

Title: Re: Advice please
Post by: camillitech on September 21, 2013, 12:29:38 PM
Hi V and welcome,

have you tried Wayne Peters at just down the road from you, I've been 'off grid' since 'Adam was a lad'  and we're just building our new 'dream home'. In the past I've done all the work myself but needed some quotes for the new build, and like you I struggled getting quotes. However Wayne was very helpful even though I never used him in the end, mainly due to the distance from Raasay. He will certainly understand your needs and be able to advise you. If you do speak to him, say hi from 'Paul on Raasay'.

Good luck, Paul

Title: Re: Advice please
Post by: brackwell on September 21, 2013, 03:11:28 PM
Do you realise that you can claim FITS and RHI payments even for off grid.   This makes these technologies self funding in just a few yrs.

You obviously need the generator for insurance so the question boils down to how much are you prepared to spend to reduce the use of the generator to x . I guess no one knows and all the offgriders on this forum have built there systems up over many years and i guess that will be your approach.  If not then 100% supply /100% reliability requires HUGE resources.  So i guess you start small and build up to reach that point x in the light of real life experience.

The pv must not have any shading issues as this has a totally disproportional effect and therefore needs to be sited with care.  You need to maximise winter generation and therefore these need to be fitted vertical or close to it. This may mean that there is a south facing possibility on a wall or even separate from the building.  If you mount the panels vertically and then put a reflective horizontal surface in front of them you can increase the output by some 50%+. PV like this is a DIY job for you but you do need MSE certification for the FITS payment.

To get you a better feel for your pv requirements then for my south facing pv system of 4kwp i only achieved your guessed requirement in Jan 2013 for 8 days and Dec 2012 6 days and have had a whole week without anything meaningful. This is not me but gives an idea -  These are two of the best that give you live readings.  Go to the winter months and imagine living with those outputs.

So really it is a balance of cost of storage v generator use v cost  Bearing in mind that batteries have a life.

Thankfully i am not a off grider


Title: Re: Advice please
Post by: biff on September 21, 2013, 08:27:10 PM
       "Thankfully I am not an offgridder"
     Hi Ken,
        If one is serious about being off grid, then they have to think in terms of multiple power sources and of course a decent lump of a battery.
        Conventional generators I suspect are too greedy on diesel,so a PMG ,low reving,linked to a small Lister,charging into the same battery bank
         through an ordinary wind turbine controller(with dump load facility) could be made to deliver 1kw for 3 hours on a ltr of red.I believe this could
        be easily achieved.The name of the game is not to burn any diesel at all but there comes a time such is in freezing fog when nothng works and
        our generators have to be called into action and that is the time we should be most economic.
      "So I guess you start small and build up to reach that point X in the light of real life experience"
        Thats exactly what I would advise because you will get to learn as you go along how precious these watts are and strive to conserve them
        for the time that they are really needed.Then as time goes by,it becomes obvious how much power the site is capable of producing both in
       Solar PV and Wind energy or Hydro.By then one is aware of what it takes to run the house and how to go about getting it.Every site is different
       Every family has different needs and living the life is the only way you can be sure that a system will work for your particular site.

Title: Re: Advice please
Post by: camillitech on September 21, 2013, 08:42:17 PM
Questions like, Studer vs Sunny Island? Dare I be bold and go with the Winston Lithium Iron Batteries?

Studer, SMA, Victron, Outback as far as 'Off grid' inverters go there's not a great deal between them. Things to bear in mind however, whilst Studer are made with Swiss precision and a quality product that performs far better than it says 'on the tin' they are a nightmare to program, back up is poor and spares basically down to a full board, which is a fortune. I own one and look after properties that have them, they are fine until some clown presses the wrong button and all the settings go 't*ts up' then it's a phone call to Switzerland or ask Rogeriko on here, he's pulled me out of the brown stuff on more than one occasion. SMA are equally good in the quality and reliability stakes with good back up and at least two forums supporting them one in the US and one in Oz. Victron are as good as anything with lots of experience in the 'off grid' market and marine applications with many of there products conforming to Lloyds and DNV standards. Outback have great backup, are the only company set up to deal with the 'off grid' market from day one, spares are easily available and they have an excellent forum for support.

Me, I'm going for SMA as much of my gear will be 'AC coupled' and they are the pioneers in that department, if I were fitting out a boat I'd go Victron as that's their main market and they're well served around the world at ports. Were I not going down the 'AC coupling' route I'd be tempted by Outback products. Studer, well I'd never buy another unless I lived in Switzerland and spoke fluent German, French or Italian  :)

As far as LiFePO4 goes, my advice is steer well clear, no inverter charger as yet supports their complex charging and no inverter manufacturer has of yet plans to produce a dedicated charging regime for them. They are the 'dogs danglies' and I work on a ferry with 216 of them on and .7 mwh  of storage, as Billi says, FLA is the way to go for 'off grid'. Also with both Winston and European battery going bust recently does that not tell you something  ;)

Good luck, Paul

Title: Re: Advice please
Post by: billi on September 21, 2013, 11:12:42 PM
Thankfully i am not a off grider



Sure you have the storage  problem  in-front of you ..... i would not like to swoop either  ;)

Title: Re: Advice please
Post by: camillitech on September 22, 2013, 06:44:27 AM
Thankfully i am not a off grider



Sure you have the storage  problem  in-front of you ..... i would not like to swoop either  ;)

Me neither Billi, I wouldn't have a grid connection unless it were for free and then I would only use it instead of Harry. Just think of all the 'fun' you would miss out on and just wait until  8)

Title: Re: Advice please
Post by: biff on September 22, 2013, 09:49:09 AM
I am only a short distance away from the mains,
                                       One pole and one day to connect.Even the 2" red mains pipe is installed out to the road and the tail were left in the meter box which I later removed.I think the connecting fee was 1138euros back in 2001.I never applied.In the beginning it was because I was still building away and based elsewhere.Each time i came here I thought it would be nice to be able to just flick the switch without bothering with the generator and I set up a small new 12v x 550ah battery bank,charged of the geni which saved a packet on fuel and drove the mobile home in which I lived while the house was being built.The house was built to sell but I got to like the place so much I sold my other place in the town instead.
      Friends in the trade,laughed and told me I was off my head,One actually told me that he spent the first half of his life trying to get out of that place,the Bluestacks.We had a good laugh over that.It was no great intelligent financial brainwave that I moved.I just loved the place for the peace and quiet,great room first class neighbours and 4 legged Biff and wise Xena could relax and enjoy.I also had my shed planned and had several dream projects up my sleeve.My grandfather was born on the other side of the hill and lived there untill he was about 12yrs old.He and my great grandfather walked away and reached Lifford where my Great grandfather died shortly afterwards.Lifford was an administration centre and for some reason people thought that food would be more readily available.My grandfather was a quiet man who seem to do the right thing.I vaguely remember him,He was very old and outlived his second wife by 10 whole years.It surprised me to learn that he had been married twice.His first wife died of consumption and his second (my granny) deliverd 7 of a second family of which my old man was the eldest.Its hard to believe that the old man was born over 100 years ago :hysteria.Maybe this goes someway to explain why,at the slightest sign of world crisis,I set sail for aldi,s or lydl and stock up on trays of tinned food.I dont think about it,I just do it. wackoold. In the years to come,we might just discover that the desire to be off grid is in the genes. :hysteria

Title: Re: Advice please
Post by: V on September 22, 2013, 09:24:30 PM
Firstly, thank you, thank you, thank you for all of the fantastic ideas and guidance. I will be asking a few more questions tomorrow and following up on this generous advice.

But I probably should chime in here and say why we want to do this. Easterdown is > 500 metres from the nearest connection to the grid, but we didn't have to buy it. It ticked many boxes for its location and amount of land we need, but deep down, we want to do this (the genes referred to in the previous post?). 

Mostly it is for the 'magic'. Batteries, electronics, photovoltaics - these are amazing inventions and discoveries, and we'd love the chance  to experience and learn about what it is to 'harness the forces of nature', first-hand. It's one of the reasons I make cheese.

Second reason is that we think that the UK is realising that it needs to sort out its addiction to burning fossil fuels. Likely future is that every household will need to have some kind of micro-generation and self storage, shared via their grid connection. Like the Internet of electricity, all homes being nodes that send and receive.

I've lurked on this list for a few months and think that all of you are great examples to anyone hoping to be self sufficient in  electricity, whether you are off grid or tied. Homes that are off grid now will provide invaluable testing, monitoring and proof of concept. We would love to be part of that.

But I'm not saying it is an easy decision for us, we are both daunted and frightened along with being inspired. All of the information you've supplied will help us get through the problems. Thanks and more later.