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MASTER THREAD: Powering house or other things with Model 3
- Thread starter Vines
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- powerwall solar home
n2mb_racing
Active Member
I meant, storage of the generator. Yeah, I agree battery storage with solar seems like a good idea, although the pricing is still too expensive. You'll never make the money back on batteries. At least not in NC where our TOU pricing isn't very different.
PianoAl
Active Member
Let's say a company wanted to create a product that could tap into the car's high voltage battery. Could that product conceivably do that by plugging into the charge port?
n2mb_racing
Active Member
Yes. You could pretend to be a DC fast charger. Not sure if the computer would shut down the charging if the voltage starts going down rather than up, but it would be interesting.
MontyFloyd
Member
Not where you live as you said, but some parts of country it will pay off within 10 years.
CA and TX a very good bets.
stopcrazypp
Well-Known Member
This is bidirectional charging, which the protocol must allow to work. I'm pretty sure the computer will not allow current to flow from battery to the charger if not configured for it.
n2mb_racing
Active Member
Maybe? The contactors just connect the battery positive and negative directly to the charge port, once the charging is setup properly. It doesn't have any way to control current flow. It might open the contactors, though, if it doesn't like what is going on.
stopcrazypp
Well-Known Member
It doesn't control the current flow, but it's constantly monitoring the current flow and voltage of the battery, and will cut things off if the charger is doing things that the car computer didn't tell it to do (which presumably current flowing the opposite direction would fall under).
My point is it's not only monitoring the voltage, but also the current and can instantly tell if it's not going the right way.
n2mb_racing
Active Member
I did almost this very thing. I used an interlock (instead of a transfer switch, which my AHJ does not require) which bolts to the load center cover and prevents the main breaker and breaker for the generator inlet jack from both being on at the same time. Since my inverter is only 120vac, I wired the connection cord so that the 120vac hot goes to BOTH hot legs of the load center. This means that my 240vac loads see zero volts, which is fine since there's not enough current to run them anyhow (fortunately my dual-fuel range it has a neutral wire and runs the gas controls off 120vac, so I can still use the cooktop).
Note that this is DANGEROUS, if your house wiring has multi-wire branch circuits (MWBC) where two 120vac hots share a neutral (a copper-saving method used by some electricians). If the two hots are not opposite phases (as would be the case with my approach), the neutral wire could be overloaded.
I've read every post on this topic, time to share my setup.
2019 Model 3
REC Pre-charge Model v3.1
Tyco EV200AAANA BMS Contactor 12-24VDC 500A
TICONN 5.9"x5.9"x3.5" Junction Box
1000W Inverter
2AWG Cable
120A Anderson Power Poles
100A Fuse Block
2AWG ring terminals and crimp tool
I desoldered the white molex 10 pin from the BEC v3.1 in order to fit the Junction box. Wires are soldered directly to the PCB through holes.
This is way more expensive than building your own pre-charge circuit, but is a higher quality finished product.
2019 Model 3
REC Pre-charge Model v3.1
Tyco EV200AAANA BMS Contactor 12-24VDC 500A
TICONN 5.9"x5.9"x3.5" Junction Box
1000W Inverter
2AWG Cable
120A Anderson Power Poles
100A Fuse Block
2AWG ring terminals and crimp tool
I desoldered the white molex 10 pin from the BEC v3.1 in order to fit the Junction box. Wires are soldered directly to the PCB through holes.
This is way more expensive than building your own pre-charge circuit, but is a higher quality finished product.
Attachments
Thanks for sharing. A couple questions ...
Why did you feel this pre-charge module was needed, rather than the "sparkless" connectors mentioned above (XT90AS, or Protek RC SQ8) ? The idea is to slowly charge the caps on the inverter's DC input, so there's not a sudden current draw on the Tesla, possibly triggering errors, right ?
Why only 1000 watt inverter ? Did you decide the Tesla's low-voltage system couldn't safely and continuously supply more ? On our Leaf, 1000 watts is also what I'm using, but when the refrigerator goes into auto-defrost it shuts down - most inconvenient.
How did you connect the inverter to your loads ? Generator inlet on the main breaker panel (as I describe above) ?
n2mb_racing
Active Member
n2mb_racing
Active Member
The antispark connectors only work to prevent issues when you first plug the inverter in while the 12v power is live. If the car goes to sleep and then wakes up with the inverter still connected, you might have issues. It might throw an error and refuse to start up because of the attached extra capacitors. The fancy solution above would prevent that.
But, I haven't tried it since I don't have a model 3 anymore.
I chose this pre-charge module because I keep this inverter connected to the car at all times for work. If the PCS goes to sleep for any reason, the module will open the contactor and pre-charge when the PCS wakes up again, preventing any errors. For the same reason I chose only 1000W to keep a healthy margin while driving for power brakes, steering, etc. From what I read the PCS has a thermal limit around 2500W, although 2000W while parked is my safe maximum.
I have a portable power station for handling higher power surges of appliances and run cords directly as needed. This setup allows me to A/C fast charge the power station.
It's worse than that, I'm brewing coffee while on Autopilot! But seriously, anyone considering this needs to use extreme caution. I know the risks and monitor the DC-DC output in real time via Scan My Tesla app to make sure I'm keeping a healthy safety margin.
One more quesiton ... not sure if the low DC on yoiur car is 12v, or higher. If higher, what inverter have you found that can handle 16vdc (or whatever) input voltage ?
There are many high quality inverters that can take up to 17.0VDC battery voltage. For example, the Victron Phoenix line has a wide range from 9.2-17.0VDC input. The highest model can output 1200VA continuous and 2200W Peak. It has a transformer inside so it's kind of heavy, but that's how it gets the Peak performance.
Amazon: Victron Phoenix 1200VA 12V 120VAC
I have the 800VA version.
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