I have a less than 2 week old Model 3 RWD. Yesterday I plugged the car into the Tesla wall connector in my garage and when the charging got to about 86%, which was about 1.5 hours of charging, it stopped charging. I went to the car and the screen was telling me the battery is low and it is shutting down. I didn't think to unplug it or open the frunk or any of that stuff so I had to figure out how to do that and I saw on the Tesla app there is a recommended method to jump start the new lithium low voltage battery. I successfully got it running again. I thought maybe it was partially my fault for having Sentry mode on or something like that. Tonight, I made sure to turn off Sentry and checked settings to make sure nothing would be draining the battery and plugged it in. An hour later, it stopped charging. I went to the car, unplugged it and the charging light was red. I went into service mode and saw that the low voltage battery was draining rapidly. It went from 76% to 20% in less than 5 minutes and the car died again. Clearly the car can charge the low voltage battery in the right circumstances as I had the car parked all day with Sentry mode on. Does anyone have any ideas about what might be causing the issue with charging that battery when charging the HV battery?
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New Model 3 draining 12V
- Thread starter chrisxtx
- Start date
Tam
Well-Known Member
I have no idea but it's time for Tesla to fix it.
Your 15.5V battery is designed to competently handle all the low voltage needs such as Sentry Mode.
It shouldn't be depleted when the Sentry Mode is used because the main battery would recharge your 15.5V battery as needed.
The car just made it to the service center and the app estimates completion on April 3. I hope that's isn't close to correct. That's 6 weeks.
Tam
Well-Known Member
If it's simple, it's just a standard Tesla QA that allows a bad batch of batteries to slip through.
It could be software issue for the new 15.5V lithium instead of the old practices for traditional 12V lead acid.
It could be a hardware issue like dc-to-dc converter while the battery is not the problem.
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Thanks for the info Tam. Here's an update.
From what the service rep said and what I have found online, it appears to be an isolation issue between the hv battery and chassis so current is making its way into the chassis and the protection system is kicking in and preventing contactors from closing. When the lv battery was fully discharged, that reset the protection and allowed the contactors to close. It looks like a long list of components could be responsible for this. The fact that it happens when hv battery charges for 1.5 hours or so could be a clue but I don't know. I suppose it could be as simple as a wire with some missing insulation touching metal.
From what the service rep said and what I have found online, it appears to be an isolation issue between the hv battery and chassis so current is making its way into the chassis and the protection system is kicking in and preventing contactors from closing. When the lv battery was fully discharged, that reset the protection and allowed the contactors to close. It looks like a long list of components could be responsible for this. The fact that it happens when hv battery charges for 1.5 hours or so could be a clue but I don't know. I suppose it could be as simple as a wire with some missing insulation touching metal.
As far as "i want another one", you will want to check your states Lemon laws.
In CA, 30 Days vehicle in service (DAVIS days) will qualify the vehicle for a lemon law claim. If they actually keep your vehicle for more than 30 days as is currently planned, if you were in CA you would be within your rights to claim lemon law and ask for a replacement vehicle.
Check your states lemon law, it may be similar. Tesla knows this too however, and will probably try to return the vehicle to you before that amount of time.
I called sales and he said that service would have to answer to that but he also suggested looking at lemon laws. I'm in NC and it looks like if the car is out of service for 20 days the lemon laws could apply if I'm reading it right.
Thats what it looks like according to a quick google search.
Things happen even with the best manufacturers, and so my starting bias is to give them - the manufacturer and their representatives - every opportunity to redress the issue.
That said, a six-week repair on a two-week-old vehicle would have me looking at my state's lemon law and preparing to go in that direction. Unfortunately, that's not nearly as simple as saying "times up, give me a new car." You'll want to document every communication you've had to date, and will have in the future.
Years ago I had a six-week-old BMW motorcycle suddenly develop engine trouble. After several lengthy visits back to the dealer (whom I had an excellent relationship with... something that helps immensely) and with the engine difficulty still undetermined... I quietly declared that enough was enough. I gave BMWNA the choice of providing me with a brand new, identical vehicle, or refunding all monies associated with the purchase. There's an inevitable corporate bureaucracy that has to be navigated with that sort of thing. So you have to be patient. But in my case it turned out well... with an identical model bike provided, which then gave me many years and many miles of trouble-free service.
That said, a six-week repair on a two-week-old vehicle would have me looking at my state's lemon law and preparing to go in that direction. Unfortunately, that's not nearly as simple as saying "times up, give me a new car." You'll want to document every communication you've had to date, and will have in the future.
Years ago I had a six-week-old BMW motorcycle suddenly develop engine trouble. After several lengthy visits back to the dealer (whom I had an excellent relationship with... something that helps immensely) and with the engine difficulty still undetermined... I quietly declared that enough was enough. I gave BMWNA the choice of providing me with a brand new, identical vehicle, or refunding all monies associated with the purchase. There's an inevitable corporate bureaucracy that has to be navigated with that sort of thing. So you have to be patient. But in my case it turned out well... with an identical model bike provided, which then gave me many years and many miles of trouble-free service.
This car will be my wife's car and she is less forgiving than I am. I nudged her towards this over a trusty new Accord to replace her old 2004 Accord.
As for the service estimate, it showed up quickly and I'm wondering if it is a worst case scenario based on the potential highest lead time replacement part which would be the main battery. I found the service diagnostic sheet for this problem on a model S and the hv battery was one of the potential replacement items.
Wrapping up this thread with an update. I picked up the car from service yesterday so it was in service a little over 2 weeks. They were able to measure out of spec values (intermittent interlock loop open) and find the root cause. A pin in connector x098 which connects to the main battery had backed out of the connector. not sure if this happened over the couple of weeks after manufacturing or if the system just took time to complain about it. The issue seems to be solved though. I don’t really have any complaints with the service experience other than it taking too long. Tesla seriously needs another service center in North Carolina. Greensboro would be a great location for one.
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