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My late 2012 model P85 is having serious 12v issues. Was first replaced proactively at an annual service last year or year before, I forget. Went in for annual service this year late Jan, few weeks later get low 12v warning. Call Tesla, they say it's safe to drive and it warns a month early. I don't take the risk and just use my backup car for a few days while I wait for the ranger to come replace the 12v.
Few days later, tech comes and my car display won't turn on. Completely dead. Glad I wasn't driving the car. Replaced and now everything is fine.
Fast forward to tonight. Yesterday had a warning pop up briefly about car needing service and might unexpectedly not be able to drive. Warning message disappears shortly when I replug the car charger and remove it. Nothing about 12v though. I figure this is a spurious alert and ignore. Tonight, get in car, unable to start and 12v low messages come on. Can't drive car and within 20 mins, now my car's monitor won't turn on so completely dead again. Getting it towed tomorrow morning to the service center.
This is highly annoying... Especially since the battery was just replaced and I had my annual service just over a month ago.
Few days later, tech comes and my car display won't turn on. Completely dead. Glad I wasn't driving the car. Replaced and now everything is fine.
Fast forward to tonight. Yesterday had a warning pop up briefly about car needing service and might unexpectedly not be able to drive. Warning message disappears shortly when I replug the car charger and remove it. Nothing about 12v though. I figure this is a spurious alert and ignore. Tonight, get in car, unable to start and 12v low messages come on. Can't drive car and within 20 mins, now my car's monitor won't turn on so completely dead again. Getting it towed tomorrow morning to the service center.
This is highly annoying... Especially since the battery was just replaced and I had my annual service just over a month ago.
Mrbry's 12V battery problems are definitely a drag and he has my sympathy for the inconvenience.
While it is possible that the replacement 12v battery is defective, the symptoms suggest that there may also be a problem with a component related to recharging the 12v battery. Unfortunately, this also appears to be a problem that is not detected by Tesla's proactive monitoring software, perhaps because the component is marginal and fails only at low 12v battery voltage.
I would suggest confirming with Tesla that they have thoroughly examined the charging subsystem for the 12v battery to confirm or rule out this hypothesis. Please let us know what they say. I would be surprised if it is just the battery.
While it is possible that the replacement 12v battery is defective, the symptoms suggest that there may also be a problem with a component related to recharging the 12v battery. Unfortunately, this also appears to be a problem that is not detected by Tesla's proactive monitoring software, perhaps because the component is marginal and fails only at low 12v battery voltage.
I would suggest confirming with Tesla that they have thoroughly examined the charging subsystem for the 12v battery to confirm or rule out this hypothesis. Please let us know what they say. I would be surprised if it is just the battery.
Just got the car back, they were nice about it and really tried to get me a loaner (which I did get) since there was obviously something else going on and it might be a while to debug. They said it turned out to be a faulty master charger controller. I believe I had the master charger replaced way back when I received the car probably early '13. So maybe this faulty charger component is to blame but maybe is a symptom of something else.... hmmm.
EV-lutioin
Active Member
EV-lutioin
Active Member
13 month old Model S (refreshed nose), 44,000km, 12v battery warning presented 1 month after the annual service visit. Took the car in last Thursday and they replaced it very quickly, in under 45 minutes. The labour charge was 1.5hrs @ $150 though :| Battery $206, labour $225, total $487.03 CAD. OUCH. Wish this was something I could do myself as I have in the past, but they've really buried the 12v battery in refreshed Model S's.
I guess the 12v battery isn't covered under the warranty, but would have been covered under the annual service plan? That's my guess as I've never had to pay for battery replacement, but then I shelled out up front for the service plan.
dhanson865
Well-Known Member
Shouldn't that have been covered under warranty? Almost $500 for a battery replacement?
Not $500 US, but 500 Canadian dollars.
For $500 US I'd expect a LiFePO replacement instead of SLA.
I'm still using a C-tek smart charger on the car every night while parked in my garage, to keep the 12v recharge cycles off for about 1/3 to 1/2 of every day.
When I'm at work, I use UMC to charge the car off 120v outlet... which is enough to close the contactors (obviously) and fire up the Dc-to-Dc converter in the car.. which powers the 12v circuits keeping the load off the 12v battery as well so it doesn't cycle during the day. It also pays for my commute energy. That's another 8 hours of every day of no cycling.
It also doesn't cycle when you're driving for the same reason. So all the commute time, another hour of the day no cycling.
No 12v replacement yet on a September 2014 delivered car.
I was "expecting" near annual replacement of this part when I bought the car. Now I've reset my expectations to "maybe every 5 years" and wouldn't be totally surprised if I got 10 years out of it if I keep up the current practices.
FYI the C-tek was on the order of $200 ... so good investment.
I live in a "cold" climate which is also friendlier on lead/acid batteries. Arizona type heat is hard on them. So your mileage may vary.
When I'm at work, I use UMC to charge the car off 120v outlet... which is enough to close the contactors (obviously) and fire up the Dc-to-Dc converter in the car.. which powers the 12v circuits keeping the load off the 12v battery as well so it doesn't cycle during the day. It also pays for my commute energy. That's another 8 hours of every day of no cycling.
It also doesn't cycle when you're driving for the same reason. So all the commute time, another hour of the day no cycling.
No 12v replacement yet on a September 2014 delivered car.
I was "expecting" near annual replacement of this part when I bought the car. Now I've reset my expectations to "maybe every 5 years" and wouldn't be totally surprised if I got 10 years out of it if I keep up the current practices.
FYI the C-tek was on the order of $200 ... so good investment.
I live in a "cold" climate which is also friendlier on lead/acid batteries. Arizona type heat is hard on them. So your mileage may vary.
JRP3
Hyperactive Member
Still about 3 times too expensive. And Tesla should cover it for free. Plus, 1.5 hours of labor charge when it actually took 45 minutes? I'd be complaining.
CuriousG
Active Member
I think this is the general practice in the "dealership" industry. The job pays X amount of time and if the mechanic can finish the job in shorter time, it benefits the mechanic. If you have an incompetent mechanic, they can spend 3hrs changing out your battery but will only get paid the 1.5hrs labor regardless.
JRP3
Hyperactive Member
That makes sense. Of course it doesn't make sense that changing a battery is a two man job that still takes 45 minutes...
Edit: To expand on this a bit further, it's criminal that a poor battery placement design causes this to take so long, and it's criminal that Tesla's poor 12V battery and DC/DC converter design causes the battery to fail so quickly, and it's criminal that these bad decisions on Tesla's part end up costing the consumer money. Elon should not be OK with this on any level.
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f-stop
Active Member
my 12V battery was replaced after the warning came up at about 14 months / 15,000km, a couple months after the first annual service - no cost to me, the repair invoice says "Pay type: Warranty".
I do have an annual service plan however, so not sure if that's the difference
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