question

Kees-Jan (SensorX) avatar image
Kees-Jan (SensorX) asked

Electric car as homebattery

Has anyone experiences with using an electric-car as home battery. Although not all cars are suitable for a bi-directional connections, i am curious to know if their is already some experiences with this. In addition how to connect it in combination with a 3-phase Victron Multi plus II setup?

ESS
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3 Answers
wkirby avatar image
wkirby answered ·

Vehicle to Grid (aka V2G) still seems to be experimental and so not very many car have this capability.
Theoretically, V2G capable vehicles could be AC coupled to the AC Out of a MultiPlus and supply loads and house battery charging that way.
I'm not sure on how V2G is to be controlled, the idea being that the network operators can somehow summon energy from cars whose owners have agreed to participate in assisting when demand is high. No idea if the vehicle owner could control this.

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Mike Dorsett avatar image
Mike Dorsett answered ·

One of the problems with using your car's battery as a home batter - or as an extension to a home battery is the operating voltage, car batteries are 380 - 800V, and so are incompatible with low voltage systems. The DC charging port (fast charge) does allow direct access to the battery though, so can be used for discharging.

On the practical side though, this will increase the wear on the car battery - which is more expensive to replace. It will also leave the battery in a uncertain state of charge when disconnected. On disconnection, the house system becomes reduced in capacity.

There are some Chinese inverters that do allow this, though.

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Kevin Windrem avatar image Kevin Windrem commented ·
Don't know about the AC coupled home systems like Enphase and Tesla but the Generac system is DC coupled at 380 volts, so maybe there's a chance with that. Still you'd need more than just paralleling batteries even of the voltages match. And you'd want to limit the discharge so you can get your car to the nearest charging station.


I know some of the trucks have fairly large inverters. Would these get involved in providing home power? That is, AC coupling the inverter output to the home energy system?

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enodev avatar image
enodev answered ·

I am trying to follow what Marc at https://www.switch-ev.com/ is doing but I am not sure it is production ready yet… although it all sounds very nice and they are taking a good open source approach so it may work in the end…

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