Home battery backup, with inputs for generator charging and future powering the house off EV as a backup...

[Obioban]

I will be building a house this coming spring. My original plan was to use a Tesla solar roof and powerwalls... but the more I read about their setup, the more annoyed I suspect I'll be them. Also, I have access to a complete, undamaged BMW i3 33kwh battery pack.

I think I still want to go with the Tesla solar roof, mostly for the looks

But, beyond that, if it's viable I'd like to make my own home battery setup from the 33kwh pack I have.

Ideally...
-By default the house will run off the pack 100% from 2-6pm (peak pricing). Any solar I generate during that time will be sold back to the grid.
-The battery would recharge off the grid from midnight to 6am
-in the event of a power loss, the house would automatically switch over to running off the battery (and then back to the grid, when grid power was restored)
-in the event of an extended power loss during poor solar, I could hook up my old 7kw generator to recharge the pack
-in the futures, when EVs can power houses, I'd like to have an input point to do that, as well, as further;/alternate backup.
-a whole house surge supressor, so the grid doesn't ruin my setup

Is this remotely viable? Any suggestion as to where I can go to read about such things? All the search results I'm finding are basically unreleased concept products from car makers... not useful. E.g. this, about the actual battery pack I have: https://www.extremetech.com/extreme/230607-bmw-i3-batteries-getting-recycled-for-home-power-backup

Thanks!

 

[Ozark Tinkering]

I will be building a house this coming spring. My original plan was to use a Tesla solar roof and powerwalls... but the more I read about their setup, the more annoyed I suspect I'll be them. Also, I have access to a complete, undamaged BMW i3 33kwh battery pack.

I think I still want to go with the Tesla solar roof, mostly for the looks

But, beyond that, if it's viable I'd like to make my own home battery setup from the 33kwh pack I have.

Ideally...
-By default the house will run off the pack 100% from 2-6pm (peak pricing). Any solar I generate during that time will be sold back to the grid.
-The battery would recharge off the grid from midnight to 6am
-in the event of a power loss, the house would automatically switch over to running off the battery (and then back to the grid, when grid power was restored)
-in the event of an extended power loss during poor solar, I could hook up my old 7kw generator to recharge the pack
-in the futures, when EVs can power houses, I'd like to have an input point to do that, as well, as further;/alternate backup.
-a whole house surge supressor, so the grid doesn't ruin my setup

Is this remotely viable? Any suggestion as to where I can go to read about such things? All the search results I'm finding are basically unreleased concept products from car makers... not useful. E.g. this, about the actual battery pack I have: https://www.extremetech.com/extreme/230607-bmw-i3-batteries-getting-recycled-for-home-power-backup

Thanks!

Last I heard Elon won't sell you a roof without a powerwall to go with it and vice-versa?

 

[Obioban]

Hmm. That might push me off the roof, too, then.

Let's assume I either can get the roof, or will use a different source of solar.

 

[dmholmes]

Last I heard Elon won't sell you a roof without a powerwall to go with it and vice-versa?

That used to be the case. I just checked and the Powerwall is not required for solar roof or panels.

 

[Ampster]

I just checked and the Powerwall is not required for solar roof or panels.

Yes, things change often with Tesla. Glad to see that option is back.

 

[Ozark Tinkering]

Shesh! Elon is a fickle one.

 

[Ozark Tinkering]

That used to be the case. I just checked and the Powerwall is not required for solar roof or panels.

So is the Powerwall available without the roof?

 

[Ampster]

So is the Powerwall available without the roof?

For sure it is from independent installers. I have heard the biggest issue is the supply of Powerwalls because Tesla is constrained by battery capacity.

 

[Ozark Tinkering]

Is the Tesla roof being produced by the same company Elon made Tesla purchase a few years ago, Solar City? It seems like the solar roof is very very expensive and is a huge drain on the company overall. Seems like they ought to be making either cars or solar systems. Not both.

 

[Ampster]

Is the Tesla roof being produced by the same company Elon made Tesla purchase a few years ago, Solar City? It seems like the solar roof is very very expensive and is a huge drain on the company overall. Seems like they ought to be making either cars or solar systems. Not both.

I feel the same way about the distraction. The positive thing about the Solar City purchase was it gave them a sales channel for the Powerwalls. I think the solar roof product is produced at a factory in New York. Solar City received huge tax incentives but had to meet employement and other benchmarks or there were penalties. Kind of like golden handcuffs. Tesla does not break out their financials so we don't know about profitability.

 

[notarichman]

i want to do something similar with different timing. i have enough solar for now, but little in the morning. if i run off the grid over night; then i
may not have enough power until 9:30 or 10am. i do have a small 1700w generator, but only want to use it for emergencies -- small gensets only
last for a few hours. So my solution is to use a charger of some nature off the grid in the morning. i bought a 10 to 15 amp 48v charger that runs
off 115vac. That won't charge 200ah batteries very quickly! So i thought about charging through my victron MPPT 450v 100amp that takes vdc
from 80 to 400vdc and maximum 18 amps, but can be set to a maximum of 15a or lower to match the whatever the charger output is. Then i would need a higher voltage power supply/charger and feed it through the PV input. Anyone know if this is a good idea or where i could buy
a higher voltage charger?