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12 volt battery warning: Experimenting for truth...

cortomaltese

Member
May 25, 2019
7
3
Tampere
Hello everyone

My name is Sean, I come from a M3LR 2020 with huge amount of technical problems, so I have decided to finally get a Model S P85D 2015 (july 15) second hand.

I got the car the 22-Jan-2021. On the 03-feb-2021 I got the warning for warning "12v battery needs to be replaced soon...".

Now, I removed it, reconnected it, the error message disappeared for a couple of hours, then I it appeared again. I called Tesla Roadside Assistance and they told me to schedule a replacement as soon as I was getting back home, there was no rush and the car could be safely driven for a couple of weeks. Fair enough

All considered, in those weeks, I have learnt how to remove and modified my car's front mask, so that I break into my frunk easily in case of lockout and jump start my car. I stored in the frunk also the jump start cables and a spare 12v battery from an ICE car, just to make sure to be self sufficient.

Back home in Finland, it took me a lot, literarily, to get the car serviced due to bureaucracy issues. The battery was finally replaced and the CCS retrofit performed on the 18-03-2021, 6 weeks and 1 days after the first warning.

Now

I have been discussing, on different Tesla Clubs (Finland, Italy and Bulgaria), how long actually the battery can survive, even in the rigid Finnish weather, before dying completely. At the service centre they thought that the usual estimated limit is 4 weeks, but they never actually tested it. I volunteered at that point, and after the CCS retrofit we have put back the old dying 12v battery (DCS-33IT) in place, so that we can actually monitor and see when the 12v will actually end up in a complete drain and get some data on the actually limit time after the warning pops up.

I will keep you up to date on my experiment and let you know when the battery will definitely die.

Yours Sean
 

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Veggen

Member
Dec 22, 2011
136
109
I hope you have plenty of patience.
A couple of years ago I drove for half a year with the replace 12V message.
Still worked when it was replaced, no issues.
 

Lasttoy

Active Member
Mar 24, 2017
1,604
851
St Augustine, Fl
My car died last year 400 miles on the way home. I was on the interstate. Towed to super charger. I tried to figure it out, no luyock. Roadside couldn't figure it out. ""Tow it 300 miles to nearest SC"". Finally a woman at Roadside said the 12v was dead. What? She said to get a truck with big batteries to jump car, charge 12v to 14.5 volts. 30 minutes on jump the car came alive. Never had error again. Last month car was acting funny. Roadside couldn't figure it out. No error message. All of a sudden, 12v error appeared. I changed the battery, it cleared all battery errors. Might be noted here. It was original battery from 2012. Florida is hard on batteries because of heat. The coolant system should keep your frunk warm, allow the hoses run thru it. Your water pumps are there, if you take out your frunk, you will see the entire coolant system. I will try to find the diagram and post it for you.
 

cortomaltese

Member
May 25, 2019
7
3
Tampere
Hello folks, here are some updates.

Since the last service, even if I have been driving all this time with the old 12v battery, I had no warning messages anymore. I think they reset some kind of counter in the system. The battery is most probably perfectly fine, otherwise it would read a voltage drop and give me the warning again.

I still drive with the new 12v in the frunk and I still have the break in setup for my mask, so that I can remove it easily in case of need (I will make a video about it tomorrow). In the meanwhile I post you my amatorial dumb proof video on how to break into your frunk in case of a lockout. I'm not a youtuber, the quality is terrible but you get the important aspects in the clip, how to release the latch. I will make a better one as soon as I have time.

 
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cortomaltese

Member
May 25, 2019
7
3
Tampere
Hello everybody

Here are some updates. The mystery is still on about my battery, which is still working perfectly after 3 months from the original warning. The last time I went to the service I managed to speak with the technicians and they told me which is the standard procedure that they follow in this case.

First they put the car in service mode, then they swap the battery with the "new model", which is supposed to be different than the old version. I attach a picture of it. the battery code is DCS-33UNCR made by Technologies.inc, (website cdtechno.com). After the swap they select on the terminal the "model" of the 12V installed and they reboot the system. The car recognise the new battery and the warning is gone. After that the car downloads and installs the latest firmware update.

"""SC finished, I continue the post at the next SC"""
 

cortomaltese

Member
May 25, 2019
7
3
Tampere
CONTINUATION

Basically after that they performed my CCS retrofit and handed me back the car, we swapped back in and I have been travelling since ten with the new 33UNCR in the frunk, ready to kick in when I will have a "lock-out". Since then no warnings and no problems at all.

Now Roadster Finland oy (Tesla Finland) has no idea actually how the warning system works. I have been interacting few times already with the technicians and seems like all they know is how to perform the swap procedure. This is bigger than I thought. We are trashing millions of perfectly working lead-acid batteries which could keep perfectly work in our cars. At the same time many of these are "under warranty", which means also a waste of time for the company and a loss of many.

Someone should investigate this further. Do you have any contacts here in EU that I can get in touch with? I would love to help us all and the company to save precious battery, pollution, time and money.

Thank you
 

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