I have mobile service coming out in a couple days. They are replacing my 2 year old 12 volt even though that wasn't the callout. They said there was a message it needed to be replaced but I never saw anything. I out a tester on it a couple weeks ago and it tested good. The only thing I can think of is this is a small battery for such high CCA. 625. I can only find 500 in the 51R SIZE. That could be the reason they fail.
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Ohmmu 12V Battery Feedback
- Thread starter LasVegas2019
- Start date
Interesting data point: I have been messing with a LiFePO4 battery of my own design. I'm getting errors even without a BMS as part of a test.
Pretty sure that it isn't the existence of a BMS causing the issue. Tesla can pretty easily test if it's a Lead Acid or Lithium battery. Charge it to over 14V, then put a load on it. Any real LA battery will drop below 12.5V right away. A lithium chemistry will stay at >13V even with a bit of load on it. It's not that the BMS cuts out in the "over charge" that tells Tesla it's a non-LA battery, it's the float voltage.
The fact that Tesla's max charge appears to stop at exactly 14.60V seems to indicate they are conscious about LiFePO4 batteries and even careful about them.
If this theory is right, a design that takes care of this would be pretty interesting, as it would need to mess with the voltage at different times (which would be also be a power loss and require new HW). Pretty creative if someone can work around it.
Send Ohmmu your information. They have developed a correction module and will soon have a battery with the built in changes. They may offer insight.
I don't think Ohmmu is going to help me, given I am making my own battery.
(not for commercial sale, just as a learning project)Updated to 2022.8.2 with the beta module battery, so far so good. No error after putting some miles with the update.
Still no word back from Ohmmu on how the module actually works or if it will also require updates over time.
Still no word back from Ohmmu on how the module actually works or if it will also require updates over time.
Unlikely that it's calendar time. I've observed that it runs the test every time you install a new battery, and I've been able to avoid the test by swapping batteries without allowing power to be lost. I'd guess (without evidence) that the tests also run either when new firmware is deployed (which reboots the DC-DC), and also after a certain number of charge cycles of the 12V battery. If this is true, use of things like sentry may really change how often the tests run as sentry reduces 12V battery use at the expense of much more HV battery use.
So what’s the deal. We get a Module sent to us? We get a discount/pro-rate on a new battery with the built in module? No discount on a new battery? I’m not hearing anything on next steps or policy and procedures.
Ski
Dunno, I’m just a beta tester lol.
For me, I received full replacement new batteries and modules, with a shipping label to send back my original battery. The original battery and replacements don’t look any different, which isn’t to say the internals aren’t different. Suffice it to say, maybe expect a new battery and module is my best guess.
Only got one battery...which of course makes me wonder if you got more??
I'm wondering if they double-shipped to you?Installed my battery and module earlier today. So far so good, but we'll see how it does over the next few weeks.
If you are on the original 12 volt battery it is probably time to replace. Either with another Lead acid or with a Lithium (Ohmmu).
Jeremy3292
Active Member
The Tesla 12V lead acid looks better every day when I look for updates on this thread…
Jeremy3292
Active Member
I don’t think you read what he said. He’s a beta tester for the NEW Ohmmu battery which still has problems apparently.
Stanwood Steve
2018 Performance Model 3
I am not sure why, but my 2018 Model 3 Performance hasn't had an issue with the Ohmmu battery since I put it in about a year ago. I'll probably jinx myself now, but I'm confused as to why my car seems fine with the Ohmmu battery and others have issues with it. I'm running software release 2021.44.30.21 currently and the car has about 72,000 miles on it now. Every time I've authorized a software update I cringe thinking that my car is going to start throwing a fit with the Ohmmu battery, but it never does. Why wouldn't "all" cars have an issue with the battery? Why are some of us using it without an issue?
My first thought goes to electronics are extremely sensitive. Some people with have issues, some won’t. When I was a beta tester for multiple cars with COBB tuning, usually had no issues with hard parts unless something was wildly off or didn’t fit… it was always when we started messing the ECU or when Cobb updated their tuner box that the code gremlins started popping up for some cars and not for others. Seems to be the same with Tesla except there’s a ton more computer monitoring — and so many more updates.
Haven’t had a single issue with the upgrades I’ve done to my Performance that aren’t monitored by the computer (of course, why would I).
Some cars are gonna be sensitive, others aren’t. Mine clearly is — and it’s part of their beta program to see if they can figure it out across the board.
This is a cool little battery that’ll probably last the life of the car and clearly improves the performance of parts that rely on the 12v — if they find a way to make it work for everyone. But just like jailbroken iPhones, the custom effort MAY require a “modder perspective” at some points. For “set it and forget it” folx (which I’m seeing across much of Tesla community), well… the newer cars will have a proprietary LFP and the Tesla acid battery is cheaper than the cheapest one at BJs. At some point maybe someone will sue about the proprietary stuff like they did Dell and Microsoft.
android04
Active Member
There is some variability in how the 12v battery is used and charged between cars due to how much owners drive and whether they use Sentry Mode or not. Ambient temperature probably has some effect too.
That's disappointing to hear.
I'm approaching week 6 of recharging my battery and doing a hard reset. It survived 1 update so far. I haven't received the new 8.2 update yet, but I have a feeling it may break the streak.
I don't drive my car a lot, maybe 3-4 times a week for less than 50 miles.
I'm approaching week 6 of recharging my battery and doing a hard reset. It survived 1 update so far. I haven't received the new 8.2 update yet, but I have a feeling it may break the streak.
I don't drive my car a lot, maybe 3-4 times a week for less than 50 miles.
I should clarify. 6 weeks of no errors after charging the battery on a charger and doing the hard reset procedure.
Also nightdown_fox said he got the error with the module and new battery, so the module may not have fixed the issue.
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