Ohmmu 12V Battery Feedback

[android04]

i bought the Ohhmu battery for my Performance Model 3. It worked great until there was an update from Tesla. Apparently, Tesla is aware that this battery is not OEM and through the software quarantines it. Ohmmu tells me they are working on it, but no solution yet. I bought a Tesla battery (which had i known there was a 50K warranty on and would have been free) battery for an additional $119, but feel a little taken. Ohmmu has stopped communicating with me, so i think i am out the 439 i paid, but you might want to think about that before purchasing...

I don't think Tesla is quarantining it. It just has different charging behavior than what Tesla programmed to detect for the OEM battery. A wise man once said "don't attribute malice to what can be explained by incompetence". I wouldn't say that incompetence applies with regards to the Ohmmu though. I don't expect Tesla to try to program in detection and different behavior for different types of batteries. It's great if they do, of course.

 

[Wennfred]

i bought the Ohhmu battery for my Performance Model 3. It worked great until there was an update from Tesla. Apparently, Tesla is aware that this battery is not OEM and through the software quarantines it. Ohmmu tells me they are working on it, but no solution yet. I bought a Tesla battery (which had i known there was a 50K warranty on and would have been free) battery for an additional $119, but feel a little taken. Ohmmu has stopped communicating with me, so i think i am out the 439 i paid, but you might want to think about that before purchasing...

If you read their email correctly, they said they will be swapping out the battery for free soon.

Fred

 

[RayK]

I just signed up on the Ohmmu site and asked them to keep me up-to-date on the status of the Model 3 battery (I don't have one of theirs yet). They said that the Rev2 variant should be shipping out in 4-5 weeks.

 

[Flybyglass]

Update 2020.36.10 finally updated today after repeated attempts. According to the Ohhmu site, there is an incompatibility with Model 3 software until they release a new battery in October. I removed my Ohhmu battery and replaced with the factory battery that I had removed when I first purchased the car. Software version 2020.36.10 would not go past 60% until I swapped and put the factory battery back in. Update progressed as t should and now after 4 weeks of failed installs it works as advertised. Now idea what a 12 volt battery would be an issue but it is a Tesla.

 

[Flybyglass]

Contacted Ohmmu about the battery issue. Since my battery was purchased in late Jan.2020. Took about 2 weeks but they sent out a Rev 2 battery no charge with a return shipping for the rev 1 battery. Have not done any software updates yet but after replacing rev 1 with the original factory battery (that I still had since it had only been used a few days) 2 software updates installed successfully. So far no issues with the rev 2 battery. Good customer service with Ohmmu. They had a problem, corrected it and made good with previous buyers.

 

[SageBrush]

I'd appreciate some feedback here whether I am understanding LiFP chemistry correctly when used in my Tesla Model 3:

So far as I can tell, the Tesla charging algrorithm charges up the 12v to 13.1v. In a LiFP auto battery, 13.1v is about 50% SoC

Dos this sound about right ?

 

[FurryOne]

I'd appreciate some feedback here whether I am understanding LiFP chemistry correctly when used in my Tesla Model 3:

So far as I can tell, the Tesla charging algrorithm charges up the 12v to 13.1v. In a LiFP auto battery, 13.1v is about 50% SoC
Dos this sound about right ?

The Ohmmu Model 3 battery has it's own Battery Management System that optimizes whatever the Tesla gives it. Ohmmu came out with a battery with their V2 BMS back in October. That's what I have since October in my Model 3 AWD.

Tesla should charge their battery (SLA/AGM) at 14.4v, and charging should be kept below 14.7v (Nominal SLA/AGM battery voltage should be 13.1v). LiFEPO4 battery nominal voltage should be 13.4v, and charging should not exceed 15.2v. So there should be no problem with LiFEPO4 batteries in a Tesla. Worries about cold-weather charging LiFEPO4 batteries should be taken care of by the BMS.