Self build..what did you do?

[Ed Davies]

3 hours ago, NeverEnoughCake said:

We are low users..about 2000kwh a year! Going with 7 x 365 LG neon mono panels, Victron easisolar48/3000/70-50-230v-c/w integral mppt charge controller, BYD -B-PLUSL 2.56 kWh 48v lithium battery...any thoughts?

 

I have similar thoughts. My usage is about the same (about 4 to 5 kWh/day). Still, to have much hope of coming close to meeting that demand I'm thinking of more than double the amount of PV (6 kW) and four time the battery capacity (10 kWh). Even then, around December it's not looking too great.

 

As @JSHarris has cross posted as I'm typing this, PVGIS is a good tool to use. On another forum I collated people's reported outputs against PVGIS predictions on a monthly basis. Generally speaking PVGIS came out at the bottom quartile; i.e., 1/4 of the time the actual output was less than PVGIS, 3/4 of the time it was a bit better so it seemed, then, that PVGIS was realistic but a bit conservative. There's a new version of PVGIS now with a number of different solar-radiation databases which vary a bit but seem to be a bit more optimistic than the old database so I image it's pretty reliable now.

 

For my site in NE Scotland with my proposed 6 kW facing just east of south at 60° elevation PVGIS predicts an output of 109 kWh for December (i.e., 3.5 kWh/day, 146 watts average). 2000 kWh per year (5.48 kWh/day, 228 watts) is obviously a bit more.

 

Something to beware of, though, with PVGIS is letting it optimize the slope. It'll pick the optimum slope to maximize year-round generation whereas off-grid you tend to want to optimize for winter generation. Theoretically to maximize December generation this far north you want the panels pretty much vertical but realistically the more even generation with a bit of exposure to the overhead sky of a slightly shallower angle is probably worthwhile. If instead of setting 60° elevation for my site I leave PVGIS to optimize the slope it picks 41° which knocks December generation down from 109 to 91.2 kWh. Even shallower angles can really nail you. E.g., 10° (as I'm visualizing for a car-port roof) will only give 40.5 kWh in December.

 

In a hilly place like Wales you need to run PVGIS for your exact site to see that effect shading by hills has.

 

My plan is to see how it goes but with the assumption that it's most likely I'll finish up getting a small wind turbine to make up the difference. I too have no option for a hydro scheme but something my site is not short of is wind. (Packed up this afternoon when a chisel blew away - I exaggerate only slightly.)

 

I too plan to use LiFePO₄ batteries. I'm not yet convinced by packaged solutions, though. The first search result for BYD B-Plus gives €1,183.00 for a single module which works out as €0.47/Wh whereas just buying individual cells can get prices around €0.35/Wh. Obviously that's without the battery management but I'm not convinced that the complex balancing systems people have are necessary or even a good idea. (You need to monitor the individual cells and some balancing at sometime is probably needed but I think it's not needed continuously and that doing it continuously might even be harmful.)

Edited April 12, 2019 by Ed Davies

[NeverEnoughCake]

Thanks JS and ED

As previously said, we tussled with this topic for a long time. 

We are totally confused by the numerous forums, articles etc for solar power. And to be honest, now just bored of thinking about it. We calculated based on our usage and hours of sun using several sites that ALL told us we would need 4 panels!! We  are going to go with 7. Frankly, it doesn't matter how many panels you have if there is no sun there is no power. We accept this, and it is why we will have a battery and generator to try and see us through those times. We have no choice, we are not going to be grid connected. Our approach will be use as little power as needed, rather than try to increase power to meet our needs. I am home all day and so can vacuum, use washing machine etc during peak production times. We have no problem sitting by the woodburner by candlelight on a cold winters night, in fact we will probably do that even if we do have power, so long as we can  keep our fridge and freezer going overnight. Having said that we could probably ditch the freezer if need be. Our electrical needs:

 

Phone/tablet charger ( 1 hour a day)

TV (couple of hours a day at the weekend)

Hairdryer( 3 times week)

Vacuum (1 hour a week)

Washing machine ( 4 times a week)

Toaster (1 hour a week) will use gas oven in winter

fridge

Small chest freezer.

Kettle (1 hour a day) will switch to gas kettle in the winter.

LED lighting.

 

We will start of with the kit I mentioned previously,  with the knowledge that we can add panels/batteries if we need to. On winter days we will use a small generator to charge battery in the morning, and see how much a trickle feed from the solar manages throughout the day.  As I said in a previous post, we take a chance that solar power will keep advancing and we can upgrade our system as and when it does.  For anyone out there embarking on off grid, can I suggest you take a look at Maximus Ironthumper on you tube. He is very informative and interesting to watch.

 

 

[jack]

I don't think battery storage is worth it with 2.5kW of PV.

 

I'd pay the £7k and get a grid connection.

[recoveringbuilder]

We tussled with the idea of off grid when we were presented with a quote of £25k for an electric connection, hubby made a lot of calls about various options but all were going to be expensive options to install and none were going to have the convenience of a grid connection. After living in a caravan for 6 months with the electricity supply coming from our neighbours garage which meant if we put the kettle on we had to turn off the water heater etc in case we overloaded the circuit it became very clear we couldn’t have lived off grid. To me electricity is one of your basic needs,

[NeverEnoughCake]

Christine

25k.!!!!! Did you have to dig your own trench as well?

I feel your caravan pain, we have been in ours for six years! But we did have an underground cable from the farmhouse because we knew it would be a long term thing. Each to their own, but we have decided to do the off grid self sufficient thing and we know we will have to dramatically change the way we do things, but it will be worth it just to be where we are. Of course you are right, electricity is a basic need but you can also keep your needs basic. Perhaps caravan living is a good way of deciding how little you really require or how much you really miss. We have been using a composting toilet for six years...our biggest dream is a flushing loo.!

[Jeremy Harris]

1 hour ago, jack said:

I don't think battery storage is worth it with 2.5kW of PV.

 

I'd pay the £7k and get a grid connection.

 

 

Me too.  The cost of the battery system and generator alone will exceed £7k, plus both will only have a life of about 10 years before they need replacing.  In addition, the generator will need to run almost 24/7 in order to keep just the baseload going, as the very small battery system isn't going to sustain it overnight.

 

To put this into context, our house is about as low energy as you can practically get for a two bedroom, two person, house.  We have 25 PV panels and there's no way that, even with a 9.6 kWh battery system (which is what I'm about to install) we can be off-grid.  We might manage to be off grid for a few days here and there, but without a generator we'd not be able to sustain being off-grid for very long, even in mid-summer.

[Alexphd1]

+1 for grid connection. 

 

We where 12k for our connection (2x builds) with ourselves digging a 200m trench. We run in a water connection aswel at the same time. Getting a digger /driver in for a couple of days ain't a major in the grand scheme of things.

[newhome]

I can’t help with any of the other complicated stuff but be very careful about how the Planning Permission is drawn up if you want to reclaim the VAT. The property needs to be able to be sold separately from any other properties or business, have no conditions of occupancy (like for the use of someone working on a farm for example), or anything that links it to a business. If it has any of those type of conditions HMRC will refuse the claim. 

 

There is a guide to the VAT reclaim process here. The first post makes mention of planning permission restrictions that would make a claim ineligible and the 6th post down highlights the cases that have been to a tribunal and most of them have been refused. If you know that your planning permission won’t have these restrictions then that’s fine but I thought it worth mentioning. 

 

 

And some specific cases that were refused due to conditions attached to the PP

 

http://financeandtax.decisions.tribunals.gov.uk/judgmentfiles/j9599/TC05626.pdf

 

http://financeandtax.decisions.tribunals.gov.uk/judgmentfiles/j10009/TC06040.pdf

 

 

[NeverEnoughCake]

Alexphd

Definitely not a major..we have a digger and my partner could do it, but it's the principle. Dig our own trench, get our own stone dust, conduit and warning tape and fill the trench back up again..and pay 7k for a couple of days labour and some cable. For us it wasn't the way we wanted to go.

[Ed Davies]

2 hours ago, NeverEnoughCake said:

And to be honest, now just bored of thinking about it.

 

That's a pity as it sounds like you're likely to fail and regret it all which will be sad for you and reinforce those who say to just get a grid connection.

 

1 hour ago, Christine Walker said:

After living in a caravan for 6 months with the electricity supply coming from our neighbours garage which meant if we put the kettle on we had to turn off the water heater etc …

 

My plan is 2 x Victron 3 kW inverters so a total of 6 kW available to use. I had all sorts of plans for automatically shedding loads to keep under that limit but in practice I find I don't actually use that much in the house I'm renting apart from when I use the 7 kW electric shower. Even running the washing machine while cooking dinner on Thursday evening it didn't go over 4 kW.

 

It seems to me there's a split in the whole off-grid thing between fairly “hair-shirt” systems such as Maximus Ironthumper talks about (just watched one of his YouTube videos) vs some really expensive turn-key systems you'll get offered if you just phone people up and that, with a bit of research and understanding, you can build something in between which will be quite comfortable 10 months of the year but need some care and thought in December and January.

Edited April 13, 2019 by Ed Davies

[NeverEnoughCake]

Thanks ed

It is the hair shirt way for us..try what we think suits us, alter it if we can if it doesn't.

Have to pop off to deal with horse faecal matter and farrier

Thanks all.

[Jeremy Harris]

15 minutes ago, NeverEnoughCake said:

Thanks ed

It is the hair shirt way for us..try what we think suits us, alter it if we can if it doesn't.

Have to pop off to deal with horse faecal matter and farrier

Thanks all.

 

Hugh Piggot is a person with a lot of practical experience of living a "hair shirt" off-grid life, and some of his stuff is well worth a read.  He relies a lot on wind generation, simply because it's pretty windy up at Scoraig, but he does have some PV generation as well.  Looking at his blog, this post gives a rough outline of the kit he's using: http://scoraigwind.co.uk/2015/11/my-electricity-supply-here/  Hugh uses a tiny PV array about the same size as the one you're thinking of, but gets most of his energy from wind generation, with just a back up generator.  He has about 38 kWh of battery capacity, which probably gives a realistic usable capacity of maybe 20 kWh or so, as he uses Rolls lead acid cells.

 

A friend of mine went up to Scoraig for one of the courses Hugh runs, and reckoned their setup was very good, but you have to be prepared for there being virtually no creature comforts there.  The whole community is really about getting back to basics, and seems to work pretty well, well enough that the community at Scoraig has been there a long time now, which is itself quite remarkable, as it's not accessible by road at all, although if you're pretty fit you can walk there, along a fairly rough path that's around 10 miles long, IIRC.

[epsilonGreedy]

21 hours ago, NeverEnoughCake said:

Going with 7 x 365 LG neon mono panels, Victron easisolar48/3000/70-50-230v-c/w integral mppt charge controller, BYD -B-PLUSL 2.56 kWh 48v lithium battery...any thoughts?

 

 

Long term boat live aboards are now switching to lithium and one reason for this is charge duration. At your stage of planning it would be easy to focus on net daily demand and capacity but in practice there is a big difference in having the noise of a generator spoiling your rural idyll for one and not two hours a day. The ability to whack a higher current into lithium is a real quality of life bonus.

Edited April 13, 2019 by epsilonGreedy

[epsilonGreedy]

19 hours ago, NeverEnoughCake said:

We have tussled with this issue for a long time.

We would have, in all fairness, connected to the grid for electricity, but we were quoted £7000.00 and we had to dig our own trench! This was money we would never have got back

 

 

I find your reasoning a bit faulty here.

 

When after 10 years you junk your first generator and knackered lithium batteries that is also money that will sit in a landfill for evermore whereas that £7000 mains cable will hmm at 50 Hz for say 50 years and zero maintenance. I get your desire to protest against lazy national institutions but don't let politics lead you to the wrong decision. 

[Thedreamer]

I would definitely go with a £7K grid connection.

 

Worth searching the forum for posts relating to connection costs.

 

We are in a rural location on the Isle of Skye and were able to reduce our connection cost by:

 

Utilising ducting instead of blinding the trenches

Using our own contractor

Applying to SSE for a grant

Considered routes and argued with the quoter to get the cost as lower as possible.

 

I have never lived off grid so can't really comment on how you adapt your energy usage around limited electricity. We might in the future if the incentives exist utilise renewable but it's not a priority at the moment.

 

A general principle that most self builder incorporate is that the big stuff relating to your build you really want to invest in once (insulation, roof etc). To me having the option to get a £7k connection, fit and forget or have ongoing off grid electricity cost would be an easy decision for me.

[Mr Punter]

1 hour ago, JSHarris said:

A friend of mine went up to Scoraig for one of the courses Hugh runs, and reckoned their setup was very good, but you have to be prepared for there being virtually no creature comforts there.  The whole community is really about getting back to basics, and seems to work pretty well, well enough that the community at Scoraig has been there a long time now, which is itself quite remarkable, as it's not accessible by road at all, although if you're pretty fit you can walk there, along a fairly rough path that's around 10 miles long, IIRC.

 

I have in laws up there and have visited a few times. I first went about 30 years ago and many of the same people and families are still there. The house we stayed in was like camping in a stone tent. We got a boat over. It is a beautiful location.

[NeverEnoughCake]

EpsilonGreedy

Thanks for your input.

Though I find your reasoning also faulty.

 

The average life of solar panels is 25 years. Say we have 4 lithium batteries, 2 controller systems and two generators in that time. Going by what we have chosen that comes to approx 18k

The average UK electric bill is £49. Month, our connection quote was 7k, assuming meter cost, digger fuel, stone dust, conduit etc for trench at 1k  that comes to approx 23k over 25 years.

 

Obviously we would have to account for generator fuel, but also assume that the cost of new solar equipment will drop in price and gain power efficiency. I imagine grid electricity charges will only continue to rise over the coming years. I can understand the lithium battery issue, but I understand that as they are now becoming a major problem with regards to the first electric car batteries coming to the end of their life, advances are being made to prolong their use in other ways. We are not swayed by politics, just by our own instinct for what is right for us. We feel this is the way forward, the more people invest in off grid alternatives the faster the technology will move. 

[Jeremy Harris]

@NeverEnoughCake,  I think most here (including me) would like to see you succeed in living off-grid, but equally some of us have experience of what it takes to do this and may think you're being very optimistic about what you'll need.  Everyone I know who lives off-grid has ended up with larger and more complex systems than they originally envisaged and all have spent way more than your budget (with one possible exception).  If you really want to go off-grid on a tight budget, then I would consider just scrapping the idea of a tiny and expensive battery and PV system, and instead invest in a reliable, and cheaper to run, low speed diesel generator, at least as an initial starting point. 

 

A chap I knew quite well where we used to live, chose to have his house disconnected from the grid, after he installed a single cylinder Lister (really an Indian Lister copy) generator, as a combined heat and power system.  His generator is in a block built shed, with a buried silencer (just a 45 gallon drum with two pipes, buried in the ground) and is very quiet when running. He runs the generator on waste vegetable oil (WVO), that he collects (given away free) in drums from a local chip shop, a fast food place and a Chinese restaurant.  The Land Rover that he uses to collect the WVO runs on biodiesel he makes himself from WVO (pretty good recycling).  He runs the radiators in his house with waste heat from the generator, as it's water cooled.  He's also added a simple heat exchanger to the exhaust of the generator to recover more waste heat.

 

The whole set up is very reliable, and seems to provide him with all the electricity he needs, as well as providing background heating to the house.  He shuts the generator off at night and starts it again the next morning, and hasn't seen the need to fit a storage battery at all (all he has is a starter battery for the generator, AFAIK).  The engine he's using is a very tough, long-lived, one, that has a reputation for longevity (50 years isn't uncommon for these).  There's a fair bit of information on the internet about these big Listers, as they are popular amongst off-gridders.  The Indian versions are generally referred to as "Listeroids", but pretty much all of them are reasonably good copies of an original Lister design dating back to around the 1920's, one that was used for years to power homes, farms and businesses here, until the grid became available.  My uncle's farm ran from one of these right up until the late 1960's, as that was off-grid.  I can't recall it ever breaking down, and I spent lots of time there when I was growing up.

 

These big Lister engines only run at around 600rpm, which is probably one reason why they last for decades.  They are also remarkable efficient, and can match the fuel efficiency of a more modern higher speed diesel gen set. 

 

Might be worth looking at, as a reliable way of delivering a modest amount of power with relatively low running cost.

 

 

 

[Ferdinand]

53 minutes ago, NeverEnoughCake said:

EpsilonGreedy

Thanks for your input.

Though I find your reasoning also faulty.

 

The average life of solar panels is 25 years. Say we have 4 lithium batteries, 2 controller systems and two generators in that time. Going by what we have chosen that comes to approx 18k

The average UK electric bill is £49. Month, our connection quote was 7k, assuming meter cost, digger fuel, stone dust, conduit etc for trench at 1k  that comes to approx 23k over 25 years.

 

Obviously we would have to account for generator fuel, but also assume that the cost of new solar equipment will drop in price and gain power efficiency. I imagine grid electricity charges will only continue to rise over the coming years. I can understand the lithium battery issue, but I understand that as they are now becoming a major problem with regards to the first electric car batteries coming to the end of their life, advances are being made to prolong their use in other ways. We are not swayed by politics, just by our own instinct for what is right for us. We feel this is the way forward, the more people invest in off grid alternatives the faster the technology will move. 

 

Someone here  - poss @ProDave - recently used pre-owned panels at about 1/3 of the cost for a solar project.

 

All you would have to do is watch and wait.

 

[richi]

54 minutes ago, NeverEnoughCake said:

I understand that as they are now becoming a major problem with regards to the first electric car batteries coming to the end of their life. 

 

You wot? ?

[Thedreamer]

47 minutes ago, NeverEnoughCake said:

EpsilonGreedy

Thanks for your input.

Though I find your reasoning also faulty.

 

The average life of solar panels is 25 years. Say we have 4 lithium batteries, 2 controller systems and two generators in that time. Going by what we have chosen that comes to approx 18k

The average UK electric bill is £49. Month, our connection quote was 7k, assuming meter cost, digger fuel, stone dust, conduit etc for trench at 1k  that comes to approx 23k over 25 years.

 

Obviously we would have to account for generator fuel, but also assume that the cost of new solar equipment will drop in price and gain power efficiency. I imagine grid electricity charges will only continue to rise over the coming years. I can understand the lithium battery issue, but I understand that as they are now becoming a major problem with regards to the first electric car batteries coming to the end of their life, advances are being made to prolong their use in other ways. We are not swayed by politics, just by our own instinct for what is right for us. We feel this is the way forward, the more people invest in off grid alternatives the faster the technology will move. 

 

But the flexibility of having a main connection is not comparable to a off grid connection. Don't think you can just compare cost as the variable

 

[epsilonGreedy]

1 hour ago, NeverEnoughCake said:

Obviously we would have to account for generator fuel

 

 

This looks like a big variable that needs to be quantified, a post in the CanalWorld forum suggests home generated electricity from a diesel generator costs between £0.50 and £1.26.

https://www.canalworld.net/forums/index.php?/topic/63233-cost-per-kwh-using-a-generator/

 

Another source based on a big 12 kva setup for a farm claims £0.25 per kwh assuming red diesel at £0.72.

 

Unless your battery bank is large your generator will be running at an inefficient low rate.

 

1 hour ago, NeverEnoughCake said:

The average UK electric bill is £49. Month

 

 

Your premise for a small scale offgrid solar/battery setup is your frugal kwh consumption rate so it is misleading to compare against the average UK bill, from your earlier posts you will be in the lower 10 percentile of UK consumers.

 

1 hour ago, NeverEnoughCake said:

our connection quote was 7k, assuming meter cost, digger fuel, stone dust, conduit etc for trench at 1k  that comes to approx 23k over 25 years.

 

 

The cost of housing a generator needs to be factored into your comparison. I assume you will want the generator remote from the house, large enough to work around and service in all weathers and nice an dry to preserve this vital piece of kit. This sounds like a very small garage or very well built shed.

 

What about annual servicing? Plus the generator will not operate faultlessly for 10 years.

[Jeremy Harris]

2 minutes ago, epsilonGreedy said:

The cost of housing a generator needs to be factored into your comparison. I assume you will want the generator remote from the house, large enough to work around and service in all weathers and nice an dry to preserve this vital piece of kit. This sounds like a very small garage or very well built shed.

 

That's a good point.  The chap I knew with the Lister generator set up had it in a purpose built concrete block building, about 8ft square.  He built the building on a substantial concrete base, that included the buried, and cast in, underground oil drum silencer.  He made the walls from a single skin of blocks laid on their side, with the roof made from pre-insulated corrugated steel sheets.  The exhaust went out through the roof, with a conical rain hood on top.  He dry lined the inside of the shed with some sort of composite timber sound proofing board, stuff with loads of holes in it, although the only real noise from the Lister is the clatter from the valve gear.

 

He could get around 4 kW or so from the generator, so enough for a basic house, with a bit of care in managing the demand.

 

2 minutes ago, epsilonGreedy said:

 

What about annual servicing? Plus the generator will not operate faultlessly for 10 years.

 

 

Servicing will be a lot more often than annually for a regularly run gen set.  People I know who live off grid do basic servicing checks every week, with oil and filter changes every couple of months, and a cylinder top end overhaul every year or so (lightly loaded generators tend to coke up the exhaust port and injector).

 

Petrol generators need less maintenance, but cost a great deal more to run, plus they don't last very long at all.  A regularly used petrol generator may need replacing after two or three years, plus, based on my experience with petrol generators, I'd say that reliability is a significant concern.  Whereas a heavy diesel will be very reliable and run for thousands of hours with just a bit of light, regular, maintenance, I've yet to see any petrol generator that's reliable in the long term.

[Alexphd1]

Regarding digging your own trench, ask them for a price to dig the trench then think of it the other way.....how much you are saving for a couple of days work. Probably a few £k! 

They only use conduit for coming into the house so a few meters max. 

[epsilonGreedy]

8 minutes ago, JSHarris said:

lightly loaded generators tend to coke up the exhaust port and injector).

 

 

Yacht engines suffer as well when charging batteries at anchor, something to do with cylinder bore glazing because the engine is effectively running at a fast idle and pushing just 0.5 kva into the batteries. A well matched home generator should work harder and avoid this danger providing charging stops before full charge.