PITA
Model 3 Performance
I'd be happy with it to supplement my static battery.
My static battery is sized to be "about right" for a Summer day. In practice that means that on days when we aren't baking and tumble drying we have excess that goes into the car. But ...
... on an overcast summer day we are short, to get through the night. V2H would give me enough top-up that would be worthwhile, and it would also mean that I was exporting less often - I export when we get a run of sunny days and I don't drive far enough to create enough EV battery space. If V2H was used on overcast days there would be battery-space for a run of sunny days.
In Summer I get around 1,000 miles a month off the roof (in addition to 90% of overall house usage). V2H would give me such a big battery that it would easily buffer the other 10% house usage (plus I have 2 EVs should could shuffle which one was providing V2H)
In Winter battery is charged overnight on Off Peak. It covers a winters day provided that the sun shines a reasonable bit AND we are not baking and tumble drying V2H would also help me with top up. Looking at a recent "average winter day" I get roughly 10% from PV, 30% from Off Peak battery charge and 60% from grid on a baking and tumble drying winter day. Of course the PV can be close to 0% if the day is overcast, and on a really sunny non-baking day I get to charge the car a little bit - but that is very very few days during winter.
I think that V2H would give me a more useful buffer than over-specing static battery for "worst case" instead of my current "big enough to rarely export to grid"
Perhaps best (for me) would be that V2H provided low AMPs all day every day (in Winter at least), and then Static Battery only used for "top up" when house is needing more. (On days when I need to drive somewhere and need a full EV battery I could do a STOP on V2H)
Yes... that is a very good idea. Perfect. Love it.
I contacted GivEnergy about this idea a few months ago...
They confirmed we could use their battery storage for a 'base load' supply to the house, and then the Powerwalls would step in for high capability demands.
Similar to your idea... but your idea would be better & cheaper.