Off grid solar car charging

[Martin]

Just as a matter of interest. I completed my “off grid” solar installation for my car charging. I have harvested 450 miles from the sun since it went live on 4th May, l make that about 9 miles a day on average and given we haven’t had the best of summers so far (I live in Devon) and I’m unfortunately shaded by a big tree, so I don’t get much after 4.00pm even on a sunny day, never the less I’m pretty pleased with that. I know that doesn’t seem like much, but I wanted to see if it were possible.

I had next to no advice from solar installers, in fact all were quite hostile to the fact that dared to do it myself. I’m from an time when we all had a go ourselves. (72 years old). They all quoted many regulations and suggested they did it for me at vast cost (nothing less than £6000) despite my constantly reminding them that this was OFF GRID and not connected to the mains in any way what-so-ever.

Anyway here’s how I did it, if anyone is interested: I got 7 x 200w second-hand solar panels and put them on my workshop roof (wired in series), I bought a new Edecoa 3000w inverter, then got 2 nearly new 24 volt 2600w lithium batteries (wired in parallel). Connected them together and it all worked. At the end of the day I’ve probably spent about £1000.

 

[Jomarkh]

What EVSE do you use?
Was it straight forward to set up as I would like to do something similar on my shed

 

[5teep]

Just as a matter of interest. I completed my “off grid” solar installation for my car charging. I have harvested 450 miles from the sun since it went live on 4th May, l make that about 9 miles a day on average and given we haven’t had the best of summers so far (I live in Devon) and I’m unfortunately shaded by a big tree, so I don’t get much after 4.00pm even on a sunny day, never the less I’m pretty pleased with that. I know that doesn’t seem like much, but I wanted to see if it were possible.

I had next to no advice from solar installers, in fact all were quite hostile to the fact that dared to do it myself. I’m from an time when we all had a go ourselves. (72 years old). They all quoted many regulations and suggested they did it for me at vast cost (nothing less than £6000) despite my constantly reminding them that this was OFF GRID and not connected to the mains in any way what-so-ever.

Anyway here’s how I did it, if anyone is interested: I got 7 x 200w second-hand solar panels and put them on my workshop roof (wired in series), I bought a new Edecoa 3000w inverter, then got 2 nearly new 24 volt 2600w lithium batteries (wired in parallel). Connected them together and it all worked. At the end of the day I’ve probably spent about £1000.

Given the average daily mileage in the UK is meant to be about 9 miles that would seem like a perfect system, at least for the summer.

 

[Martin]

I drive an MG4 now, but I've had two MG zs since 2019.
Its very easy to set up, the instructions with the EDECOA inverter are easy to follow, but in short; 2 cables come from the solar panels straight in to the inverter, 2 cables come from the batteries straight into the inverter, connect the ordinary electric socket to the inverter. Oh and don't forget the earth, I used a straight forward copper earth rod. MOST IMPORTANTLY, remember that the solar panels are live and generating power during daylight, which is probably when you are working.

 

[Bam Bam]

Its very easy to set up, the instructions with the EDECOA inverter are easy to follow, but in short; 2 cables come from the solar panels straight in to the inverter, 2 cables come from the batteries straight into the inverter, connect the ordinary electric socket to the inverter. Oh and don't forget the earth, I used a straight forward copper earth rod. MOST IMPORTANTLY, remember that the solar panels are live and generating power during daylight, which is probably when you are working.

Impressive stuff.

We've got the expensive MCS option (with a backup system) which cost a hell of a lot more than yours!

Sometimes wonder if I could DIY a couple of panels on top of the south-facing shed roof to supplement our system.

So does the power stored in the battery get discharged into the car when you plug it in (if there is insufficient solar available)? I guess that means that if you are out during the daytime you can still store several hours of generation to charge the car overnight?

 

[Martin]

The 2 batteries will store about 5 KW and that will give me about 20 miles. It takes about a day with sunny weather to fully charge and about 2 days with dull weather to fully charge, as I said earlier, giving about 9 miles a day on average. I usually let the batteries charge up during the day then plug the car in, using the granny charger, for a couple of hours or so in the evening.

 

[siteguru]

Pedant mode on ... kW is a charge rate, kWh is a charge capacity. Your batteries thus would hold 5 kWh.

 

[andyMG4]

Well done @Martin There is nothing rocket science about this...

We've now got about 8kW of panels, 5-6kW of Inverters and nearly 14kWH of batteries (2 VW ID3 modules bought used, it had done 110 miles before ). Mostly been running for 2 years now. All DIY / no feed into grid.

Probably cost £7-8K. From March-Oct the grid is mostly off, do Hot Water, house supply and 2 EVs from the panels alone.

 

[Rolfe]

That's very impressive indeed. What do you do if you need additional heating on a chilly spring or autumn evening, or even in a cold snap in summer?

 

[andyMG4]

What do you do if you need additional heating on a chilly spring or autumn evening, or even in a cold snap in summer?

If that's for me, out in the sticks so heating is Oil - as is Hot Water unless enough solar.

You might feel "off grid" is a bit of a cheat regarding oil Also use Starlink / Mobiles, so landline not used any more...

 

[Rolfe]

I'm in the same position as you as regards the oil. I just wondered how you managed. Of course the oil boiler needs electricity to run. Do you have a system where your solar is able to handle that without calling on the grid?

 

[Julian Edwards]

Just as a matter of interest. I completed my “off grid” solar installation for my car charging. I have harvested 450 miles from the sun since it went live on 4th May, l make that about 9 miles a day on average and given we haven’t had the best of summers so far (I live in Devon) and I’m unfortunately shaded by a big tree, so I don’t get much after 4.00pm even on a sunny day, never the less I’m pretty pleased with that. I know that doesn’t seem like much, but I wanted to see if it were possible.

I had next to no advice from solar installers, in fact all were quite hostile to the fact that dared to do it myself. I’m from an time when we all had a go ourselves. (72 years old). They all quoted many regulations and suggested they did it for me at vast cost (nothing less than £6000) despite my constantly reminding them that this was OFF GRID and not connected to the mains in any way what-so-ever.

Anyway here’s how I did it, if anyone is interested: I got 7 x 200w second-hand solar panels and put them on my workshop roof (wired in series), I bought a new Edecoa 3000w inverter, then got 2 nearly new 24 volt 2600w lithium batteries (wired in parallel). Connected them together and it all worked. At the end of the day I’ve probably spent about £1000.

Presumably you also had a solar charge controller. I would be tempted to add a few more panels as the bulk of the system is in place.

 

[QLeo]

Just as a matter of interest. I completed my “off grid” solar installation for my car charging. I have harvested 450 miles from the sun since it went live on 4th May, l make that about 9 miles a day on average and given we haven’t had the best of summers so far (I live in Devon) and I’m unfortunately shaded by a big tree, so I don’t get much after 4.00pm even on a sunny day, never the less I’m pretty pleased with that. I know that doesn’t seem like much, but I wanted to see if it were possible.

I had next to no advice from solar installers, in fact all were quite hostile to the fact that dared to do it myself. I’m from an time when we all had a go ourselves. (72 years old). They all quoted many regulations and suggested they did it for me at vast cost (nothing less than £6000) despite my constantly reminding them that this was OFF GRID and not connected to the mains in any way what-so-ever.

Anyway here’s how I did it, if anyone is interested: I got 7 x 200w second-hand solar panels and put them on my workshop roof (wired in series), I bought a new Edecoa 3000w inverter, then got 2 nearly new 24 volt 2600w lithium batteries (wired in parallel). Connected them together and it all worked. At the end of the day I’ve probably spent about £1000.

That's really interesting, and helpful too, thanks. We're off-grid and have wondered about either setting up a separate system or enhancing the existing system to be able to charge the car. (We're in the far north west of Scotland). The cost of your system is especially impressive, as my sums couldn't get close to that - the best I could get to was about £2-£3k. In the end, we abandoned the idea, as we thought we could get years of charges on public chargers from the cost of the system. It's helpful to know it's do-able though.

It would be interesting if you could report back later in the year to let us know how far into the year this setup works for you.

 

[andyMG4]

Of course the oil boiler needs electricity to run. Do you have a system where your solar is able to handle that without calling on the grid?

Grid is turned off at house entry... and the whole house (inc boiler) powered by batteries / inverters. Theoretically you could have the inverters and grid on together, and use the inverters to ensure there is no feed back to grid - but grid can be used when required. I say theoretically, since somebody might judge that is the grid connected to a DIY system, which would of course not be permitted ?

 

[Rolfe]

This sounds similar to something my installer said, that my system (quite conventional) wouldn't power the house in a power cut, however another modification could be added at any time that would permit that. I didn't do it because we don't have prolonged power cuts here, but I still might.

I sometimes wonder how I'd heat the house in a prolonged power cut, and the obvious answer is that dirty great tank in of kerosene in the garden, with whatever I have in the house battery powering it.

 

[crite40]

How brave you are to try this at 50 degrees North! Here I am just North of Auckland and about 36 degrees South. I had installed commercially a 5 kW solar roof and Inverter to return excess power to the mains supply. When I got the car 2 years ago, I used the money from my old "Gas Buggy" to get a charging system interfaced to the inverter. This means that the car gets the excess power BEFORE the return to the grid. The total cost was about $12,000 NZ dollars (say 6,000 UK pounds). Although I am in my 80's I have still done almost 20,000 km in the 2 years. So far the car is run on about 95% solar power and my power bills are tiny, in fact mostly so called "fixed charges". Fortunately when I built this house 19 years ago I had it orientated NSEW, so I have a big area, clear of shade for my 16 panels. It has always had solar water heating and an experimental 2 PV panel installation I used to run the lighting. The little home charger is only used in longer cloudy periods in winter and to balance the cells every month or so. Today in the middle of winter and partly cloudy it is generating 1.8 kW.

 

[Roger]

Just as a matter of interest. I completed my “off grid” solar installation for my car charging. I have harvested 450 miles from the sun since it went live on 4th May, l make that about 9 miles a day on average and given we haven’t had the best of summers so far (I live in Devon) and I’m unfortunately shaded by a big tree, so I don’t get much after 4.00pm even on a sunny day, never the less I’m pretty pleased with that. I know that doesn’t seem like much, but I wanted to see if it were possible.

I had next to no advice from solar installers, in fact all were quite hostile to the fact that dared to do it myself. I’m from an time when we all had a go ourselves. (72 years old). They all quoted many regulations and suggested they did it for me at vast cost (nothing less than £6000) despite my constantly reminding them that this was OFF GRID and not connected to the mains in any way what-so-ever.

Anyway here’s how I did it, if anyone is interested: I got 7 x 200w second-hand solar panels and put them on my workshop roof (wired in series), I bought a new Edecoa 3000w inverter, then got 2 nearly new 24 volt 2600w lithium batteries (wired in parallel). Connected them together and it all worked. At the end of the day I’ve probably spent about £1000.

Sounds a brilliant project, well done! We have 14 solar panels, 13.5kWh batteries and type 2 charger. Our mk1 MG ZS is mostly powered by our lovely free sunshine.
Would appreciate photographs of your setup.

 

[Bam Bam]

This sounds similar to something my installer said, that my system (quite conventional) wouldn't power the house in a power cut, however another modification could be added at any time that would permit that. I didn't do it because we don't have prolonged power cuts here, but I still might.

I sometimes wonder how I'd heat the house in a prolonged power cut, and the obvious answer is that dirty great tank in of kerosene in the garden, with whatever I have in the house battery powering it.

Givenergy offer several backup options.

We got one of the cheaper (manual) options added when the EV charger went in.

Thankfully we've never had to use it and hopefully we never will!

It can't replicate the grid fully but has enough power to run most things. Certainly enough to run a boiler!

 

[Rolfe]

It's likely that I'll get something like that at some point, maybe when winter arrives.

 

[Bam Bam]

It's likely that I'll get something like that at some point, maybe when winter arrives.

Yeah, we have a very reliable grid in the UK.

We had one significant outage a few years ago when they blew up the local cooling towers and the dust triggered a fire at some local electricity infrastructure.

It was actually the Summer I wanted it for - I didn't want to be missing out on solar because the grid was down for an extended period. With the car it is a great option to just put it in there once the house battery is full.