V2H recommendations

The cheapest solution is probably a dedicated battery and a ten year old ICE car. Whether you also want solar panels is separate question.

Apparently new dedicated battery packs cost about £1k per kWh, and an old EV might have 25kWh available for around £4k.

I'd have thought a Nissan Leaf - they certainly seem to be quite cheap used for what they are. But that's just a guess - and I gather it's early days, and the home connection can be spendy.

More like £1k for 5kWh last time I looked. At that price the case for a home battery must be pretty good for many people - with or without solar.

Indeed. But I'm not sure how well the old batteries hold up once the capacity drops significantly. Time will tell.

If you buy big-name (Bluetti/Jackery/Ecoflow etc)

A LiFePo4 48V 150Ah "golf cart" battery also costs about £1k (for over

Unless I am imagining it, there was an item on Top Gear some years ago about the long term performance of the Nissan Leaf - and the range reduction over time - possibly down to less than 100 miles ?

Yes, I think high battery degradation due to lack of liquid cooling?

EON are suggesting £5,400 for 10.6kWh; would you use 25kWh during a day?

Repeatedly recharging to 100% is a fairly sure way of killing an EV battery over time, especially if left standing at that level instead of driving away immediately.

The range of my 10 years old Nissan Leaf is now 80 Miles. Fortunately I only do 40 miles trips at the most.

There also seems to be a fire risk with at some Leafs (Leaves?). See for example:

That isn't much is it! Our plugin hybrid skoda that is six years old manages 25 miles or so.

A car battery at 12V/80Ah ~1kWh) cost about £100

Fogstar will sell you a 48kWh lithium iron phosphate battery for £5000.

You will need to add a charger and inverter.

Their products appear to be of good quality.

John

If you're prepared to DIY and don't mind forgoing the 'car' aspect, you can just stick in a cheap microcontroller to translate between the CANbus of the battery and whatever your inverter speaks:

For some vehicles there are also some homebrew solutions that do enough of the 'fast charge' protocol so that the car opens the battery contactors to put the battery on the DC side of the charge port, at which point you can hook up a solar inverter to pull current out. See openinverter.org wiki/forum for people hacking in this area.

The Leaf does officially support V2G but it uses CHaDeMo and needs an external inverter, which is rather pricey. I think it's just doing the same as those homebrew solutions, but in a £1-2k productionised box.

Other vehicles with V2L / V2H / V2G use the onboard charger in reverse as the inverter. V2L (~3kW) is more common than V2H/V2G (7+kW). I'm not up to date as to what the best recent models for official V2x are.

The Leaf battery degradation is caused by lack of liquid cooling and a particularly sensitive early chemistry. Most other EVs are holding up well in terms of degradation.

Of course, this means you can pick up Leafs for cheap because while a 40 mile range EV might not be a lot of use to drive, it's still a ~10kWh usable battery.

Theo

Quick search:

But £5k is not far beyond the cost of a new gas combi . . .

They will sell you an outdoor cabinet:

It's an interesting thought experiment as to whether you could charge up one of those on an EV tariff and power your heating during the daytime. eg if you had a 5 hour off peak window in your tariff, pulling 48kWh would be 41A continuous - not impossible.

My heat pump winter consumption is 30-40kWh per day, so charging it at an EV tariff of 7p instead of a flat tariff of 27p would save £7 per day. Over a

Theo

The Eon offer includes inverter, isolater, installation, warranty, and is still much less than £1 per kWh.

The BMS is only 150A, you'd need 200A

But might the EV tariff go away within 8 years?

Lower down the page it says 300A