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12v battery issues

I bought the car that Ohmmu, then called something else, had their prototype battery in. I still have that prototype battery 3 years later. We've put more than 190,000 mi on the vehicle since then too. Battery still works fine. just the lack of hassle from having to change the batteries makes it worth the price difference!

And, in case you're wondering, I get nothing from them for talking about their batteries and I certainly don't work for them. not that I would refuse something! Just in case they're listening. :)
 
I have a battery jumper pack stored in the frunk at all times for this reason. I've had a 12V battery give warnings and a 12V dying all of a sudden leaving us stranded. 12V jumper in the frunk allows us to get into the car and drive since the frunk can be manually opened. If you're getting a battery jumper, be sure to pull it out and charge it every 3 months.
 
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My message just popped up....weak batteries tend to fail going into the colder months. It was a good run nearly 4.5 years on a 12v.

Only had to wait 3 days with mobile service. If you are seeing 3 to 4 week backorders, call other service centers to see if they have inventory.
 
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So, I can relate to this. My 2008 E90 M3, which I've owned since new, went through 3 (three) of the 59lb AGM OEM batteries in 8 years. Two were covered by the warranty period, which if you do the math, meant two batteries in four years! The third one made it a bit longer, and the car driven on long trips frequently and was kept on a tender in salty times etc, but they still died early and often.

I installed a 7lb 34Ah lifepo battery with internal BMS and low-voltage safety cutoff in June of 2016, with a custom-made mount. Dropped 50lb, and never think about the battery anymore, though the car cranks longer below 30f if it cold-soaks, that's because it's a high-CCA demand 12:1 compression V8, not something we need to worry about on an EV. A Drop-In LiFePo seems like a great option for a car that doesn't need the cranking amps, just the constant draw, especially if you're plugging in every night and not worried about cold-soaking down to sub-20f on a frequent basis such that the chemistry just stops working.

For anybody on the fence about doing this, just an anecdote from my personal experience that a well-engineered LiFePo is a great option.
 
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2018 Model X.
On Monday, get the 12 volt battery warning message. Set up mobile appointment for Thursday. Car driven short distances in the interim, and then plugged in for charging overnight. Thursday morning, car is bricked and dead in my garage. Luckily, mobile was able to change the schedule service from office to home, so they came to the house and changed out the battery.
My lesson: when this warning comes up, drive to a SC and get a new battery! I had, literally, three days before the car was dead.
 
2018 Model X.
On Monday, get the 12 volt battery warning message. Set up mobile appointment for Thursday. Car driven short distances in the interim, and then plugged in for charging overnight. Thursday morning, car is bricked and dead in my garage. Luckily, mobile was able to change the schedule service from office to home, so they came to the house and changed out the battery.
My lesson: when this warning comes up, drive to a SC and get a new battery! I had, literally, three days before the car was dead.

I had no warning, car 16 months old! I walked up to the car in the garage, the door unlocked and started to open then the car bricked! Door partially opened so towing would be difficult. Service Center is 200 miles away and mobile service unavailable for 4 days. I ordered an Ohmmu battery and installed it myself.
 
Have any of you tried to charge the 12 volt battery directly? Would be interesting to see if the life of the 12 volt battery is extended if charged with a battery tender say every 2 months

I didn’t try since the battery stunk up the garage like rotten eggs. Voltage was down to 10 Volts, dead. Besides last thing you want is to be stranded again.

I believe the battery failing early is due to the rearview camera being on constantly when parked in the garage. For some reason it’s hot (122 degrees). The car rarely sleeps now and yes I’ve checked the following:
  • Reset password, no third party apps enabled
  • Summons standby turned off
  • Cabin overheat protection turned off
  • Sentry Mode set to exclude home
    • Turned off Sentry off completely
  • Air conditioning off
  • Range Mode off
  • Tested unplugged from charger overnight, same issues, camera hot, intermittent to no sleep
  • Checked USB DashCam (formatted drive and also changed)
Please check your rearview camera and see if its hot to the touch. Strangely enough, after driving I check the camera and its cold but while parked in the garage (idling) the camera gets hot and the car won’t sleep. This seemed to have gotten worst with 2020.44 but although I have had this issue before. I believe this is what is eventually draining the 12 V battery. I can’t imagine why the camera is enabled with sentry off.
 

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