Just wondering.
We now have 85kWh Musan Leaf.
It charges of our EmonEVSE / OpenEVSE at 11kW.
No complaints.

However - what would it take to take the next step and get to a V2H situation.
I checked the V2G | CHAdeMO page and contacted the manufactures there.
Most of it seems vaporware.

The Wallbox Quasar V2G seems to do what it should do but is fairly expensive at about 4.500 euro’s.

Here is my question:
Is anybody aware of an opensource V2H Chademo device for the European continent?

Looking forward to hear from you.

Best regards,


Wallbox Quasar and Indra v2g are the only options for v2g that I’m aware off.

We’ve been recently testing the Quasar unit, it’s possible to control the unit via modbus which has a lot of potential for smart integration:

I also have battery upgraded e-NV200 with a CAN bridge and the Quaser works fine with that.

That’s a chance we might be getting some Quasar units to resell via OpenEnergyMonitor for a reasonable price. If you want a unit sooner you could try looking on ebay.

Yes interested in one of those units - thanx!

When I first learnt about V2G I was quite enthused and thought it would be great to use the EV as a home battery.

Then I found a recent article by TU Delft that doubted the economic benefit. As it would significantly shorten the EV battery life. And you would need to replace your EV battery a lot sooner, say within 4 or 5 years of use. And in the mean time you would be suffering a shorter EV range.

Later I read when an EV battery is declared “end-of-life”, it could be repurposed as a home battery. It would still be good enough for that.

A home battery today is still way too expensive to be economical. You easily pay 5 times the price of a car battery on a €/kWh basis. So if you want a home battery, it could still be economical to use your EV’s battery, wear it down, get it replaced and hold on to your old EV battery as a separate home battery so you can stop using the EV as one.

That is all fine, but if you factor in that a Quasar sets you back 4500 € and you would only use it for 5 years, this whole scheme makes absolutely no sense to me any more. For that money you can install a home battery with a moderate energy content (5kWh). And even if it is only one tenth or less than the car’s battery, 5 kWh gets me through the evening / night. And it can charge from my PV even if the car is not there.

All of the above is based on NMC battery chemistry. LiFePO4 would do a lot better. And also be a lot safer. New chemistries (Sodium?) may do even better and be cheaper.

So in the face of all this, my opinion is to not bother with V2G with my NMC chemistry EV and save the range. The reverse is much more interesting, I believe.

I have solar PV producing over 50kWh on a nice summer day. Meaning I’m feeding a lot to the grid. When nobody wants it. And when I want to charge my car, I may need to take power from the grid, which costs a lot more than what I get for the energy I’m putting in it. And I may want that power when everybody else needs power.

So to maximise use of your own power and take stress away from the grid, it seems to me it may be interesting to have a hefty home battery, 50kWh or more, that can soak up all the PV energy I have in the summer and use that to charge my car when I’m back home in the evening. The cost of such a battery is prohibitive today. But it may not be in the future (5+ years from now).

That puts the whole V2G thing in question. Certainly if a Quasar costs 4500€. Makes no sense to me.

So I have serious doubts now about V2G. It may prove to be a hype and the wrong thing to do. The theory for V2G to work is:

  1. You drive to work and connect your car to a smart grid charger there.
  2. The solar power you make gets used by your car, you need the grid for that.
  3. You drive the fully charged car home and put it in the V2G station. You car gets you through the evening / night and there is still enough range to get you to work the next morning.

I see a lot of issues with that theory. Hauling your home battery to work every day and needing an oversized grid are the obvious ones. The hefty home battery that charges your car at night without needing the grid at all seems to be a lot better to me for grid investment. I think V2G is doomed.

I can follow your reasoning Phillipe.

I am here for V2H not V2G - so I want to use the car to power my home, not help grid activities.

The grid might supply the battery at certain times but it is mostly to go around moments of high tariffs - see below.

The C-level draw of this activity on the battery are minimal compared to what the car is build for - I cannot see how it would affect your battery.

100% feed in tariff stops here in the Netherlands per end of 2024.

New wind parks on the North Sea come online - one started last week.

More and more hours of energy surplus are being generated from that source.

It is reasonable to assume these moments will get more and more often also in wintertime.

There are now energy suppliers that cater to that scenario - (Energy Zero, and they are white label for ANWB Energie and MijnDomein Energie)

So you pay a hefty price when using energy on hours of high demand and more or less get it for free on hours of low demand or hours of energy surplus.

Rules and regulations are in development where you have to give notice (not correct English I fear!) to the local fire brigade when you have more than 0,8 kW electricity storage in the home. No one is enforcing this of yet but this is coming.

Your car, and in particular the Nissan Leafs and ENV’s, Outlanders, Miev/C Zero etc. are then a fairly cheap way to get this going.

I upgraded our Nissan Leaf to a 85kWh battery - I don’t believe it has NMC chemistry but I could be wrong.

I agree that the Quasar is a lot of money.

The Indra is another device that seems to work.

Scale is the name of the game here.

I made inquiries into quite a few suppliers of similar devices mentioned on chademo.com.

Mostly vapor ware including leading brands like ABB (who build a very nice device indeed - but helas, not for sale…)

It is therefore that I asked about a chademo / DC version of openEVSE/emonEVSE.

For now it seems too much to ask but who knows maybe some clever engineer comes up with a kit or a design for a kit.

We have two years from now to get this going - it seems like a smart way to go - especially for all-electric homes.

It might be cost prohibitive for now, but that situation might change quickly.

Best regards,


Hello Antoine,

I also understand your reasoning, I have been in that place too. But I changed my mind. I even thought for a moment that was a good reason to buy an EV. Mine is a Peugeot e208. We love it, do 99% of our errands with it. Costs nothing to use. We have a Merc on the driveway catching dust until we decide to do a trip that is more than the range of the Peugeot. That is not very often. V2H is not necessary to make it a really smart buy.

“Terugdraaiende teller” or “Saldering” as you call it in the Netherlands has ended for me in Belgium for almost two years now. That is why I added PV panels. With the old system making more than you used was not compensated. Now it is. I am with ENECO, they give a fair price for injection.

I went for OpenEVSE because it is the ONLY solution that you can make work with the DSMR smart meter and not have to install a lot of proprietary junk. I charge with surplus, the meter stays at zero import / export. Works very well.

A home battery is always home. Some you can put outside. Would that also need to be reported? Add up al your mobiles, laptops, vacuum cleaners etc… and everybody will need to report… I don’t know what the impact would be… I believe a solar PV installation is also not without risk for the fire brigade? I did not have to report that (yet?).

I am almost certain your Leaf is NMC. 85 kWh is really big and NMC is probably the only technology that is compact enough to fit that in a LEAF. And you are right to say V2H will only load to 0.1C. But I trust the Dutch researchers in TU Delft, hier wordt heel goed nagedacht.

The ABB thing is used by an engineering outfit in Zelzate and also in south Germany somewhere, in test phase. I asked them and they confirmed it is not for home use yet.

If I had 4500€ to spend today, I would go for a LiFePO4 home battery. Safer, many more cycles, actually making a slim chance to live the 15 years it needs to pay itself back.

I have another reason for this: my EV cannot do V2H. CCS is not ready for that yet. It may never be.

So all this is just my opinion based on my situation, knowledge and reasoning. By no means the “absolute truth”. But I thought it would be good to publish my reasoning as I believe not many think about it the way I do yet. And I always like to hear more arguments and opinions to help sharpen mine :slightly_smiling_face:.

For the last couple of years, I have been using an Indra V2G system with a 62kWh Nissan Leaf as part of the UK Government sponsored Ovo trial. For personal interest, I have been monitoring battery condition using the LeafSpy Pro smart phone app (I was very keen to know whether V2G was knackering my battery!) So far, for us, the deterioration is not a problem. It certainly does not look we will have to change the battery after 4 or 5 years. Do you have a link to the TU Delft data, Phillipe?
Here’s my battery deterioration using V2G compared with expected deterioration off the internet (Geotab - EV Battery Degradation). Hopefully the graph will display correctly.

The rate of deterioration has been quite slow, but there has been a sudden 1% drop recently. This occurred while we were on holiday, and the car sat idle for 3 weeks. It was not connected to the V2G, and coincided with the 40degC heatwave. So the impression I’m getting so far is that V2G does not cause massive deterioration, but that high temperatures may be more of an issue. In future, I’m going to ensure the car is parked in shade!

Interesting, It’s been demonstrated in several studies that V2G can actually increase battery longevity since EV’s that are used for V2G spend less time at 100% SoC which coupled with high temperatures is the worse thing for longevity. Compared to driving the current drawn by V2G is very low so very little heat will be generated in the battey during a V2g session.

Sounds logical to me.
If we charge the battery to 100% more than 10 time a year it’s much.
We always use the 80% option.

I believe the Indra people now start a test of their own. I registered but I expect to be turned as I am not in the UK. Too bad - home is as ready for it as it will ever be.


Would I be able to set this up…
I have emonpi + openevse + Nissan Leaf (2014) but about to get second ev that openevse could be used for.

I have solar arrays totalling 10kw and a Tesla powerwall2

Would a quasar play nicely with the rest of the setup / be able to pick up the slack when the Tesla runs out?

Did you use the wallbox specified energy meter or did you work out how to control the quasar via emonpi?

Many thanks

In our testing with a Quasar unit the minimum charge / discharge current was 6A (1.4kW), this is a bit high for V2H (load following) to work in most domestic houses. Often the load of the house is much less than 1.4kW. The conclusion was the Quasar is more suited to V2G applications where it can export at a higher current continuously or maybe small office / industrial location which has a higher power requirement

In our testing we were using a Wallbox specified energy meter and enabled V2H.

Thank you for pointing that out… indeed my base load is around 500w.
I would assume (dangerous) that at the point of the quasar kicking in (tesla powerwall flat or excess of 5kw req) the excess would then be sucked up balanced by the powerwall?
not ideal as losses in DC-AC-DC

The Quasar won’t kick in when operating in V2H home until your load is 1.4kw or above. You can trigger the Quasar manually to export which an excess would get hoovered up by your power wall. It think it may be possible to force the Quasar to run at a slightly lower power if you control it via Modbus, but it will never go lower than 1kW, I imagine efficiency will also be poor since it’s designed for 7kW V2G export.