Advice needed on waking up Model 3 [salvage car sitting for 1 year unplugged]

[jjrandorin]

Why did you let it sit for so long with out charging?

The answer to that question is in another thread this OP started, here:

Tesla Model 3 PCS replacement [Salvage model 3]

Hello Tesla fans. Recently I bought a salvage Tesla Model 3. The car had a bad PCS and I have replaced it with another one. Sadly the battery won't charge because of "Incompatible software versions" error. Any idea how to sort this?

teslamotorsclub.com

 

[Gauss Guzzler]

I strongly believe Tesla has through about the car being left unused for prolonged periods and they have built in a protection feature which shuts down the power consumption once it reaches a critical level. The main battery shows about 230 volts when measured with a multi meter at the terminals. See the video here -

230V is pretty low, I wonder if that guy actually succeeded? I don't know the minimum voltage for Tesla's chemistry but it's surely around 3V/cell and that Youtuber is at 2.4V/cell. Have you measured your pack?

When the voltage gets that low it can damage the cells in a way that makes them dangerous to charge so I suspect the charging system is just refusing to try. You can manually charge the pack up to 300V, manually balancing it as needed and then see if the car will acknowledge it, but if you don't have the equipment to manually charge a 300V battery handy, you might not be the right person for the job. I recommend contacting a battery rebuilder like Gruber Motors to discuss your options.

 

[Flybyglass]

Is the main battery disconnected under the rear seat?

 

[Wennfred]

Is the main battery disconnected under the rear seat?

Yes read the instructions I posted above.

 

[Frank99]

I think Gauss Guzzler has it right. The pack has fully shut down to try to save itself. There’s likely an “undervoltage cutoff” circuit that’s doing this, that isn’t under control of the computer.
It’s likely your only possible resolution will come from applying a low current (1A perhaps) 300V supply to the battery and waiting until the battery voltage comes up. If the car can connect to the battery after that, hallelujah, the bms system should bring it back up and balance it and life should be good. If it doesn’t, then likely only Tesla can reset the low voltage cutoff.

 

[stopcrazypp]

230V is pretty low, I wonder if that guy actually succeeded? I don't know the minimum voltage for Tesla's chemistry but it's surely around 3V/cell and that Youtuber is at 2.4V/cell. Have you measured your pack?

When the voltage gets that low it can damage the cells in a way that makes them dangerous to charge so I suspect the charging system is just refusing to try. You can manually charge the pack up to 300V, manually balancing it as needed and then see if the car will acknowledge it, but if you don't have the equipment to manually charge a 300V battery handy, you might not be the right person for the job. I recommend contacting a battery rebuilder like Gruber Motors to discuss your options.

The absolute lowest cutoff I have seen for lithium ion is 2.5V per cell. 2.4V is way too low (unless there is some other parasitic voltage drop).

 

[stopcrazypp]

You might have killed your main power. Li-ion batteries are not made to sit uncharged for a year. I think the manual states somewhere that you should not leave it unplugged for extended periods.

Tesla had anti-bricking protection built in (and also a bottom buffer) since the early days when some Roadsters were bricked.
Plug It In

That said, if you decide to discharge the pack to absolute 0%, according to that blog, it can still auto-recover if plugged in within 30 days. But beyond that it's anyone's guess.

 

[stopcrazypp]

Lithium Ion batteries can sit for up to 5 years actually. They have very little self-discharge. The problem is that the car's computers always have some parasitic draw which runs the battery down.

I think that multi-year rating is for a fully charged battery cell. But it's different story if you discharge the cell to absolute 0% (2.5V).

Tesla's system in the Model 3 draws about 1 mile of range per day, so it's never going to be anywhere close to years of sitting (even if it started fully charged, which I suspect this pack did not).

 

[disem]

Yes, the car connects to WiFi and still no connection to the app. If you see my first post, it won't even connect to a Tesla technician's computer. He suggested it may be because the main battery does not power up some modules. And again as in my initial post - can you charge the main battery directly at the terminals? I hear some people use their cars to power their homes, so there must be a way.

 

[disem]

Thanks Gauss Guzzler! I see you have already answered my question above!

 

[lolder]

300 volts is a low HVB, 230 is kaput. Only Tesla can service this even if they would but probably won't since it's salvage. A new HVB is probably the solution.

 

[StellarRat]

The dilithium crystals are depleted. Warp drive is not possible.

 

[dmurphy]

I recommend contacting a battery rebuilder like Gruber Motors to discuss your options.

This right here is the greatest chance of success. If Pete Gruber (no relation to Hans) can’t bring that battery back, nobody can.

 

[wifi442]

Curious what became of this. My guess is it won't charge because there's no battery to charge. I read that a lot of salvage Teslas have the HV battery removed and then the car is then put back together (with no battery) and sent back to the auction. I hope that's not the case here.