Power wall questions

[BillyGee]

Anyone know if a power wall can output in 3 phase? I'd like to use it for home charging and solar storage, but I want to know if I can avoid buying an inverter with a third leg.

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[ajdelange]

No. It's split phase - input and output. That's fact that you can verify by looking at the Powerwall specs. What follows is more speculative.

I don't think you will be able to get to 3 ø by adding another inverter as you don't have access to the battery itself and wouldn't be able to connect it. Beyond that each Powerwall probably only has one inverter as there really isn't a need for a second one in a split phase device. The obvious way to get 3 ø out of powerwalls is to interconnect 3 Powerwalls and I am fairly sure they are able to be so interconnected but you would have get with Tesla to be sure. The installation guide doesn't give any hints as to how to do this.

There are various ways to get 3 ø from split phase. The most elegant, of course, is a rectifier followed by 3 inverters (all packaged in a single box). Then there are "converters" that derive the 2nd and 3rd phases with phase shifting networks and, probably the most common kludge is the "kicker motor" arrangement. What sort of 3 ø load(s) have you got?

 

[ajdelange]

Got a bit interested in this and found, to my surprise, though I shouldn't have been, that you can get VFD controllers for 3ø motors with single phase (240 V) input for $100 - 200 from Amazon. Some of them accept speed sensors, braking resistors etc. and have vector control i.e. they have several of the features of our cars.

 

[alan auerbach]

Question: Given that (1) there's a new Tesla service center in my town (in Canada), and (2) I have a 220v outlet in my garage (run off my stove and dryer -- don't know the amperage), can I expect to hire Tesla to send somebody to convert my outlet to a CT charger -- or will I have to find my own electrician? Thanks.

Oh -- and can somebody tell me what a "Reaction score" is?

 

[ajdelange]

Your truck will come with a Universal Mobile Connector (UMC). This is a small box with a cord on the end of which is a connector that plugs in to the Tesla. At the other end one plugs in various adapters. The car comes with one that plugs into the box at one end and has a regular 120V wall plug at the other. With this you can charge your truck from any 120V outlet in your house or garage. Other adapters are available for the more common 240V receptacles such as the NEMA 14-50R which is commonly used for electric ovens. Find out which receptacle you have (search NEMA plugs) and then go to the Tesla store to see if they have an adapter for it. With proper adapter you won't need an electrician. Just plug the adapter into the UMC, its wall plug into the wall and the end of the long cord into the truck.

Should you want a more elegant and faster charging solution (and one that leaves the UMC in the vehicle which is really where you want to keep it) then you would put in a Tesla HPWC (High Powered Wall Charger). This would require the services of an electrician. No, Tesla does not come out and do these installations but they will recommend an electrician from a list they maintain.

Go back and look at your post. At the bottom you will see a thumbs up symbol with ajdelange next to it. This indicates that I reacted to your post by indicating that I liked it. You will see that under your name your reaction score has gone up by one.

 

[alan auerbach]

Your truck will come with a Universal Mobile Connector (UMC). This is a small box with a cord on the end of which is a connector that plugs in to the Tesla. At the other end one plugs in various adapters. The car comes with one that plugs into the box at one end and has a regular 120V wall plug at the other. With this you can charge your truck from any 120V outlet in your house or garage. Other adapters are available for the more common 240V receptacles such as the NEMA 14-50R which is commonly used for electric ovens. Find out which receptacle you have (search NEMA plugs) and then go to the Tesla store to see if they have an adapter for it. With proper adapter you won't need an electrician. Just plug the adapter into the UMC, its wall plug into the wall and the end of the long cord into the truck.

Should you want a more elegant and faster charging solution (and one that leaves the UMC in the vehicle which is really where you want to keep it) then you would put in a Tesla HPWC (High Powered Wall Charger). This would require the services of an electrician. No, Tesla does not come out and do these installations but they will recommend an electrician from a list they maintain.

Go back and look at your post. At the bottom you will see a thumbs up symbol with ajdelange next to it. This indicates that I reacted to your post by indicating that I liked it. You will see that under your name your reaction score has gone up by one.

 

[alan auerbach]

A double thanks, A.J.

 

[Jax]

Does a power wall enable faster charging of your vehicle versus traditional grid?

 

[Crissa]

Does a power wall enable faster charging of your vehicle versus traditional grid?

No.

It just stores power from cheaper sources and feeds it back into the grid, car, or house as needed or allowed.

If you're spending enough to get a Powerwall you will jave access to the highest power Level 2 charging available. Though it is merely the electrician that's getting you it, not the Powerwall.

Charging speed at home rarely matters, since it's usually overnight or whatnot.

-Crissa

 

[ajdelange]

No. When at a SuperCharger (or other compatible fast DC charger) the charger is really the charger and connects more or less directly to the vehicle battery. It (the charger) determines the power going to the vehicle under instruction from the vehicle.

When charging from an AC source (including a power wall) the actual charger is in the vehicle. It (the charger) determines the rate of charge in this case too. People call the thing on the wall (HPWC, JuiceBox, Mamba...) a charger but it is really EVSE (Electric Vehicle Support Equipment) that interfaces the charger in the vehicle to the mains in the building. The actual charger in Tesla (and Rivian and...?) are limited to 48A draw from a 240V mains circuit which is 11.52 kW. They will take less than that if the driver wishes to charge at a slower rate or if the EVSE isn't capable of supplying that much (EVSE connected to a breaker of capacity less than 60A is not capable) but never more.

The PowerWall is similar to the vehicle in that it has a battery pack and rectifier and is connected to the building mains. The big difference is that its rectifier is bi directional so it can send energy from the battery to the building if the utility power goes down.

A single PowerWall only holds 13.5 kWh and is only capable of supplying 5 kW of power. Thus rather than increase the rate of charge to your car/truck were you to rely on the PowerWall to charge it during an outage you would have to reduce the charging rate in the vehicle to 5 kW or less and would discharge the PowerWall in less than 3 hours only aquiring 13 - 15% SoC increase in the charge of a vehicle with a 100 kWh battery. The latest couple of versions of Teslas software have new features which interface with the PowerWall which, I presume, means that it will crank down the charge rate to the appropriate level for the number of PowerWalls installed. Note that 8 of them could fully charge a 100 kWh vehicle battery and do it at the maximum rate the vehicle charger can accept but no faster. Eight PowerWalls can deliver 40 kW to the building but no more than 11.52 kW to your truck.

 

[Crissa]

Yes, a level 2 'fast charger' is really just a smart outlet that has a method to tell the vehicle how many amps are available. (Unlike the normal outlet that doesn't and you hope you don't overload it.)

-Crissa

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