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MASTER THREAD: Powering house or other things with Model 3 12V battery

cali8484

Member
Jul 8, 2018
83
45
California
Wow, apparently we might not need to do this much longer.... The charger already in our Model 3/Y might be able to produce AC power.
Tesla quietly adds bidirectional charging capability for game-changing new features - Electrek

Though, I don't really understand that schematic. Why would it support three phases? I don't know if model 3s outside the US support three phase power charging...

Tesla uses 3 phase AC motors so that's the reason for 3 phases. Frankly, the article is somewhat misleading because it does not mention that many converter topologies are "ready" for bi-directional conversion. There are many more things required beyond than what's shown to make practically usable inverter/charger.
 

cali8484

Member
Jul 8, 2018
83
45
California
I have a dedicated backup battery (non Powerwall) at the moment, I can use my Tesla to charge that safely to power the house. It's more expensive, but I really don't want to brick my $60K vehicle. I prefer to use that to charge another battery or device that runs the inverter. I can do it without lifting the frunk or the trunk or any wiring.

What do you mean by "brick"? If you mean permanently disable the car then that's unfounded fear.
 

n2mb_racing

Active Member
Jun 14, 2014
1,108
677
durham, NC
Tesla uses 3 phase AC motors so that's the reason for 3 phases. Frankly, the article is somewhat misleading because it does not mention that many converter topologies are "ready" for bi-directional conversion. There are many more things required beyond than what's shown to make practically usable inverter/charger.

Yes, but I'm assuming they are showing the schematic of the charger, not the motor controller. I don't really understand why they would have a three-phase controller there.

But, I am not as familiar with the Model 3. On the Model S, the charger is separate from the motor controller / inverter.
 

cali8484

Member
Jul 8, 2018
83
45
California
Yes, but I'm assuming they are showing the schematic of the charger, not the motor controller. I don't really understand why they would have a three-phase controller there.

But, I am not as familiar with the Model 3. On the Model S, the charger is separate from the motor controller / inverter.

Sorry I think I looked at it backwards. The 3 phases are so the charger can work with either 2 or 3 phase AC power.
 

mattack4000

Active Member
Oct 1, 2017
2,317
897
CA
You cross a wire, you blow a fuse, you are looking at $$$ to repair it.

I buy myself an external battery and adapter, I can trickle charge the external battery.
 

cali8484

Member
Jul 8, 2018
83
45
California
You cross a wire, you blow a fuse, you are looking at $$$ to repair it.

I buy myself an external battery and adapter, I can trickle charge the external battery.

Yes, you can definitely blow fuses if you don't know your way around a battery inverter. As alternative, a car audio installer can set it up to safe usage.
 

n2mb_racing

Active Member
Jun 14, 2014
1,108
677
durham, NC
yes at 5 amps or 10 amps. I keep it at 5 to keep it safe. Keep sentry mode on and you can charge your battery without lifting the frunk

Gotcha. Although, Sentry mode burns a lot of power. But, yeah, I think that would work pretty well for emergency purposes. 12V at 10A should keep a fridge running...
 

mattack4000

Active Member
Oct 1, 2017
2,317
897
CA
Yes, I meant using the 12V outlet to power a charger for another 12V battery, which then provides the surge power to start the compressor. The 12V on the car just needs to provide average power, which for my fridge is about 100W

AC/DC inverters are not the most reliable appliance, I would prefer to take the direct load else somewhere else other than the car. With that said, my system cost me $2500. I should just install a PW at 11K and got it a day.
 

mattack4000

Active Member
Oct 1, 2017
2,317
897
CA
AC/DC inverters are not the most reliable appliance, I would prefer to take the direct load else somewhere else other than the car. With that said, my system cost me $2500. I should just install a PW at 11K and got it a day.

I can charge both units with the 12v connector in the car
 

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cali8484

Member
Jul 8, 2018
83
45
California
AC/DC inverters are not the most reliable appliance, I would prefer to take the direct load else somewhere else other than the car. With that said, my system cost me $2500. I should just install a PW at 11K and got it a day.

There is value in being portable. Perhaps you can get some foldable solar panels to charge your power station.
 

Knightshade

Well-Known Member
Jul 31, 2017
11,150
14,458
NC
Wow, apparently we might not need to do this much longer.... The charger already in our Model 3/Y might be able to produce AC power.
Tesla quietly adds bidirectional charging capability for game-changing new features - Electrek

Though, I don't really understand that schematic. Why would it support three phases? I don't know if model 3s outside the US support three phase power charging...



This appears to have been debunked elsewhere

Well, we got bidirectional in there after all?
 

n2mb_racing

Active Member
Jun 14, 2014
1,108
677
durham, NC
Thanks for sharing. So, the schematic published by Electrek is clearly wrong. Now, it makes me wondering if they do any fact checking before publishing content.

Yeah, it was close. It looks like transistors on both sides, but upon closer inspection they have just diodes on the output side. I watched the video. I could see why the other teardown engineer got it wrong.
 

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