How do I charge my Model Y using only excess solar power?

[preilly44]

It seems like my ChargeHQ is not working as expected. I have a 34kw system with 8 PW2s, 3 of which are PW+s. I have not received PTO yet so I want to charge our Teslas when the PWs are full so my system doesn't shut down solar. While it does charge the cars, it will only charge them at a slow speed, like 5-8 amps (which has my solar system only producing 3KW). If I manually turn up the cars amps to say 20 amps, the solar system will produce 5-7.7KW.

I thought it was supposed to automatically maximize amps based on how much solar it could be producing when the batteries were full?

 

[power.saver]

It seems like my ChargeHQ is not working as expected. I have a 34kw system with 8 PW2s, 3 of which are PW+s. I have not received PTO yet so I want to charge our Teslas when the PWs are full so my system doesn't shut down solar. While it does charge the cars, it will only charge them at a slow speed, like 5-8 amps (which has my solar system only producing 3KW). If I manually turn up the cars amps to say 20 amps, the solar system will produce 5-7.7KW.

I thought it was supposed to automatically maximize amps based on how much solar it could be producing when the batteries were full?

ChargeHQ doesn't know how much your solar system "could" produce, only what it is producing. Since you are pre-PTO, Tesla is limiting your production, so ChargeHQ can't see the maximum amount. Once you have PTO, it should work as advertised. Right now, by increasing the amps in the car, you are drawing more power, and Tesla then lets the solar produce more.

 

[miimura]

ChargeHQ doesn't know how much your solar system "could" produce, only what it is producing. Since you are pre-PTO, Tesla is limiting your production, so ChargeHQ can't see the maximum amount. Once you have PTO, it should work as advertised. Right now, by increasing the amps in the car, you are drawing more power, and Tesla then lets the solar produce more.

Agreed. If I was designing ChargeHQ, I would be looking for exports to absorb with car charging. In the power limited pre-PTO situation, you would have to increase charging amperage blindly and then look for net consumption from the grid to then retard car charging, the opposite of the normal way to do it.

 

[roblab]

I find it much simpler to sell excess power to the grid and then use it when I need it. Sure, PG&E charges me a small fee for the use of their "batteries", but mostly I use my 3 power walls. Unfortunately, 3 power walls only hold about 20 kwh of power, while my car needs two or three times that much on any given day. The grid is far cheaper than buying another half dozen power walls or so. It's like me wanting to buy enough batteries to match what I have in my cars: 100 kwh for the S and another 70 or so for the 3 is a bunch of storage.

I have 11 kw of solar. On a good day I might generate enough to top up my cars, but there are days when I don't need any topping up. Thankfully the grid allows me to store excess and retrieve it as needed, for a very modest usage fee.

 

[miimura]

I find it much simpler to sell excess power to the grid and then use it when I need it. Sure, PG&E charges me a small fee for the use of their "batteries", but mostly I use my 3 power walls. Unfortunately, 3 power walls only hold about 20 kwh of power, while my car needs two or three times that much on any given day. The grid is far cheaper than buying another half dozen power walls or so. It's like me wanting to buy enough batteries to match what I have in my cars: 100 kwh for the S and another 70 or so for the 3 is a bunch of storage.

I have 11 kw of solar. On a good day I might generate enough to top up my cars, but there are days when I don't need any topping up. Thankfully the grid allows me to store excess and retrieve it as needed, for a very modest usage fee.

There is a reason that the ChargeHQ comes from Australia. Many places like Australia don't have Net Metering like California currently does. When you have a Feed In Tariff that only pays a fixed small amount for what you export into the grid, you are much more motivated to use your own solar when it is produced. The California utilities are trying hard to move away from Net Metering too. Most likely, your days are numbered for access to such customer advantageous grid rules.

 

[StreetGuardian]

Optiwatt app support said

“Congrats on the new tesla! We can create custom plans to include your daylight saving hours. However we do hope to add solar integration to the platform by the end of 2022!”

My original question to them was:
“Hello, my new model Y is arriving in August (first Tesla). I have solar panels on the roof to power my house along with Tesla power walls. Is the Optiwatt app useful if I only want to charge during sunny daylight hours? It seems to be for off peak hours which wouldn’t apply to me”

 

[burjoes]

I have a Tesla, a wall connector, 15KW Tesla Solar Roof and 2xPowerwalls. I have "Value of Solar" (not net metering) and I've been very frustrated about this! I am so glad to have found this thread and just installed the Charge HQ app! I can't believe it's free and it works perfectly! Today I'm putting out 8KW, my PW is full, and I'm dumping to the grid. Meanwhile my car is near empty. If I charge at 48A, it will pull from battery, with those associated losses, then it won't be full during the night if I need it. So my best move is to only charge from excess solar, which now I can finally do!

 

[power.saver]

I have a Tesla, a wall connector, 15KW Tesla Solar Roof and 2xPowerwalls. I have "Value of Solar" (not net metering) and I've been very frustrated about this! I am so glad to have found this thread and just installed the Charge HQ app! I can't believe it's free and it works perfectly! Today I'm putting out 8KW, my PW is full, and I'm dumping to the grid. Meanwhile my car is near empty. If I charge at 48A, it will pull from battery, with those associated losses, then it won't be full during the night if I need it. So my best move is to only charge from excess solar, which now I can finally do!

Yes, the Charge HQ App is great. I use it all the time to automatically charge my EV as soon as the PWs are full.