Powerwall(s) required for Solar model 3 charging?

[BlueMoon1224]

Thinking about going Solar for the house. Have talked to several vendors and getting conflicting info. One says I would need 2 Powerwalls to charge my model 3 std+, another says 1 would do it albeit somewhat slower. Anyone have experience with this? Using Tesla wall connector in the garage.

 

[Sophias_dad]

Not sure I understand the question. I think you technically don't NEED any. If your panels are providing power and your car is absorbing it...

A single powerwall appears to have the capacity to store 13.5 KWH, so even FOUR won't fill a model 3 SR+ battery. You also should be checking how much solar power you can get from your expected panels, as you could easily put in more powerwalls than your solar can generate in a day.

Regarding powerwall OUTPUT rates, https://tesla-cdn.thron.com/static/...response-content-disposition=inline;filename="powerwall-plus-datasheet-na-en.pdf" tells me that a single off-grid powerwall can supply 7 kw continuously with no sun, so an SR+ can just about max out the output(32Ax240V=7.68kw).

 

[DuncanM]

I've researched this to some extent. Certain Sunny Boy SMA grid tied inverters can output 120/240v direct from the invertor to a load, with no need for a battery buffer. Theoretically, the inverter can directly charge an EV during daylight hours.

 

[jjrandorin]

Thinking about going Solar for the house. Have talked to several vendors and getting conflicting info. One says I would need 2 Powerwalls to charge my model 3 std+, another says 1 would do it albeit somewhat slower. Anyone have experience with this? Using Tesla wall connector in the garage.

The desire for powerwalls has zero to do with "charging your model 3". It makes no sense to use solar energy that was put in a powerwall to charge your car.

A single powerwall has 13.5kWh of storage. A model 3 RWD / SR+ has roughly a 60kWh battery. Trying to use a powerwall (or 2) to charge a vehicle is like using a AA battery to charge 2 D batteries. Possible? Sure. Does it make sense? No.

Powerwalls are backup for your home, and allow you to use the PV you generated during the day at night in the manner in which you wish, but it makes no sense to plan to put that energy into your car. Its for backup instead of a generator, or using to run your home when the sun is down, not for charging the car.

The reason you are getting different answers from your PV installers should be because they are recommending a number of powerwalls based on your projected PV (solar) size and yearly usage in general. Its not very good to get 1 powerwall with more than about 7kWh of solar for a technical reason I am not going to get into here.

In any case, abandon the idea of "I am getting powerwalls to charge my tesla" cause that is about the worse usage for them you can come up with.