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Model 3 12v Battery issues, monitoring, Aftermarket replacement

hcdavis3

HCD3
Supporting Member
Mar 3, 2019
2,306
1,515
02571
I didn’t see this service bulletin. Took my car to service at Tesla Dedham Ma. They replaced my 12 volt battery at 1700 miles on my 3. I’m curious as to what the issue was with the original battery. They didn’t replace it with a lithium ion battery. I was hoping. Anyone else seen this. Thanks.
 
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ewoodrick

Well-Known Member
Apr 13, 2018
5,285
4,270
Buford, GA
There are battery failires with any batteries. Of course they wouldn't replace with a lithium ion battery, it isn't a good cost/performace trade-off. If it was, they'd have one in there to begin with.
 
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hcdavis3

HCD3
Supporting Member
Mar 3, 2019
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Did you take it in for this service? Or was it for something else? No, I haven't seen this service bulletin.
The car was built July of last year. I did take it to Dedham MA service center and the advisor said there was a bulletin on the battery. Must be build date specific. Replacement was lead acid.
 

hcdavis3

HCD3
Supporting Member
Mar 3, 2019
2,306
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There are battery failires with any batteries. Of course they wouldn't replace with a lithium ion battery, it isn't a good cost/performace trade-off. If it was, they'd have one in there to begin with.
Thanks Ed. I did ask for a Li ion battery...service advisor laughed.
 
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hcdavis3

HCD3
Supporting Member
Mar 3, 2019
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Are there other makers of Lithium 12V batteries other than Ohmmu ?
Morning j. I think I’ve see a couple but can’t remember their names. Google 12 Volt lithium batteries and you’ll come up with a bunch. I’ve heard of issues with the lithium batteries installed in a model 3. You’d think a 12 volt car battery would be the same regardless of the kind, but somehow the 12 volt lithium batteries installed in a 3 cause error messages. What I’m most curious about is there a savings when driving due to the weight reduction.
 

mike123abc

Member
Aug 20, 2018
408
823
Norman, OK
My car was made in 8/2018 and my 12v battery failed and had to be replaced.

The battery is an odd size, it is pretty small for a car battery. It also has a gas vent on the driver's side that hooks up to an exhaust tube.

Lead acid batteries do specific things very well. Maybe the model Y will be able to finally get rid of it, it will be interesting to see if they can get a replacement worked out.
 

Wennfred

Supporting Member
Supporting Member
Apr 4, 2019
3,042
2,117
San Diego
Purchased a Ohmmu lithium battery so that at 1700 miles I won’t have to deal with a failed lead acid one. Battery should arrive tomorrow Wednesday, shipped from Ohmmu at a lower cost then on Amazon. Main reason I am going this route is the weight, 11.5 Lbs the Lead acid one is 28 Lbs. Every bit counts.

Fred
 

hcdavis3

HCD3
Supporting Member
Mar 3, 2019
2,306
1,515
02571
Purchased a Ohmmu lithium battery so that at 1700 miles I won’t have to deal with a failed lead acid one. Battery should arrive tomorrow Wednesday, shipped from Ohmmu at a lower cost then on Amazon. Main reason I am going this route is the weight, 11.5 Lbs the Lead acid one is 28 Lbs. Every bit counts.

Fred
Let us know how it works. There’s gotta be some energy savings due to weight loss.
 
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LGA737

Member
Dec 19, 2017
63
242
NJ
I don’t think your Tesla is gonna like that battery. Tesla charges and discharges that battery based on a very specific battery specification. Have you been having problems with the OEM battery or is it just for the weight savings? 11.5/3900 = 0.3% reduction in weight. You I don’t think you’ll see a measurable improvement in anything with that small a reduction. That said I’m interested to hear how it goes.
 

hcdavis3

HCD3
Supporting Member
Mar 3, 2019
2,306
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02571
My wife’s LR is a year and a half old with 30,000 miles on it still on original 12v battery BTW. Mine has 5,000 also on original battery.
What’s the build date of your car? Mine was built July of 2018. The service bulletin may be for specific build dates.
 

derotam

Member
Oct 31, 2018
863
810
Oak Hill, VA
I didn’t see this service bulletin. Took my car to service at Tesla Dedham Ma. They replaced my 12 volt battery at 1700 miles on my 3. I’m curious as to what the issue was with the original battery. They didn’t replace it with a lithium ion battery. I was hoping. Anyone else seen this. Thanks.

There are issues with using Li-Ion for the 12v, one of which being a temperature issue. To use a Li-Ion 12 battery you would need temperature management(cooling/heating) to keep the battery in the correct operating range. Without that and in a cold environment and the 12v Li-Ion battery wouldn't work well.
 

Wennfred

Supporting Member
Supporting Member
Apr 4, 2019
3,042
2,117
San Diego
Got the Ohmmu Lithium Battery in today, the swap took around 5 minutes, what a major difference in weight, I mean pulling the lead acid battery i had to lean against the fender to get the leverage to pull it out, almost weight as much as a normal ICE battery even for its small size. The Ohmmu is ultra lite at 11.5 Lbs and was the same fit as the OEM one. Everything came up inside, Nav station, sound system etc. took the ride around the neighborhood and no issues so far. Will drive it to work tonight and see how it goes.


Fred
 

evM3Sekar

Member
Mar 31, 2019
57
41
Cincinnati, OH
Got the Ohmmu Lithium Battery in today, the swap took around 5 minutes, what a major difference in weight, I mean pulling the lead acid battery i had to lean against the fender to get the leverage to pull it out, almost weight as much as a normal ICE battery even for its small size. The Ohmmu is ultra lite at 11.5 Lbs and was the same fit as the OEM one. Everything came up inside, Nav station, sound system etc. took the ride around the neighborhood and no issues so far. Will drive it to work tonight and see how it goes.
Couldn't find info from a quick search on these topics. Anything your research revealed?
  1. Does it void any of Tesla's original warranty?
  2. Ohmmu's BMS test and data?
Sounds promising on paper - awesome indeed! Curious about what you find out.
 
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Wennfred

Supporting Member
Supporting Member
Apr 4, 2019
3,042
2,117
San Diego
First work day out, night time drive 62 degrees and back home this morning on the Ohmmu Battery, round trip was 40 miles, no glitches, no error codes, all worked fine... sound system, Nav station, Wireless Phone Charger, Easy Entry Seats, horn, auto door, auto Frunk latch. The new battery is holding up well.

Fred
 

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