Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Ohmmu Battery & 2020.28.6 update

This site may earn commission on affiliate links.
I’m sure at some point I will and have been both eyeing and toying with the idea of either replacing the OEM with the Ohmmu when I get the indication or pre-emptively striking and replacing it now and keeping the OEM as a backup. OR waiting for the OEM to fail, THEN having Tesla replace it, THEN get the Ohmmu and have the new OEM as a backup. See my dilemma? Lol.
So far no issues but I’m sure they’re coming.Ski
I hear you and that is exactly what I did. Dropped in the Ohmmu and kept the OE battery in climate controlled storage, trickle charged to peak capacity and conditioned every 6 months.
Sitting there as a backup in case of any Ohmmu issues. The other piece of mind item, Ohmmu's good long term warranty.
 
Excellent explanation and details. Your report makes sense to me. I have similar experiences & results, minus your recalibration discipline- 10/03/18 delivery of AWD LR, 31,500 mi, >80% freeway miles, driven about 5-6 days per week, terrain: Bay Area freeways & cities. “Max range” is 287 miles when reading Tesla App, charging about 1-2x/ week on a level 2 charger at work, topping off to 90% at home; charging to 100% abt once/month. And my cumulative Wh/mi is 247. I think I’m in the same ballpark as you and probably about 90% of all similar configured and drive habits (drive a bit faster on freeways than most and conservatively on streets; do like to “open her up” every now & then...).
Thank you for giving me more piece of mind that my vehicle is charging “as expected.”
 
If anybody wants to monitor the 12v battery voltage and current there's a few ways to do it. One is to get a dedicated 12v battery monitor that connects to the 12v battery and sends the data to it's dedicated smartphone app through Bluetooth. Another is to use an OBD scanner and Scan My Tesla app. And the final way is to buy the Ingenext module for all Model 3s that has a nice dashboard with the 12v battery info displayed (as well as other nice goodies like Drift Mode) BONUS Module - For Tesla Model 3
 
  • Like
Reactions: lUtriaNt
good data all, i had hoped it was something similar with those with hw 2.5 and those with 3, but seems someone borked that idea..

ive a 2020 march build and hw3 fsd. at 28.6 update i got the error about a week after the update (had ohmmu battery since april). now im 32.2 and still see the error after i reboot the HV.

waiting to see if the newer update will fix.

i reached out to ohmmu and he seemed to suggest he has a better idea of what is going on and may be able to make a firmware adjustment to his batteries. not sure how those of us with these batteries will fare once he figures it out but as it stands the ohmmu battery i use is strong and always showing 13.x volts.
 
i reached out to ohmmu and he seemed to suggest he has a better idea of what is going on and may be able to make a firmware adjustment to his batteries. not sure how those of us with these batteries will fare once he figures it out but as it stands the ohmmu battery i use is strong and always showing 13.x volts.

thanks for the update. I actually had the error return randomly while driving on Friday. Normally it’s shown up while starting my day. Hopefully Sean can figure it out!
 
  • Like
Reactions: lUtriaNt
Does it block the screen and not allow any other touchscreen inputs? Is it deletable or must you do the HV reset to get rid of the warning and allow other screen inputs?

Ski
It shows up like any other alert under the fsd visualization but it’s not deletable you have to do the HV reset but it’s just a nuisance it doesn’t affect inputs or anything
 
Copy that...thanks. My car turns 2 next month....(Sept)...I’m low miles (8,000) and not in a hot climate however am nervous about mine failing without notice. Toying with the idea of throwing an Ohmmu in “pre-emptively” to preclude being stuck with no vehicle and no warning other than “your car is dead replace 12 V” and all that that goat rope involves trying to get service from Mobile OR a 100 mile drive EACH WAY to the nearest SC after an apparent 2-3 week appointment via the app. Also,toying with throwing a battery monitor on with app notifications but not sure how much warning THAT will even give me.

Ski
 
Copy that...thanks. My car turns 2 next month....(Sept)...I’m low miles (8,000) and not in a hot climate however am nervous about mine failing without notice. Toying with the idea of throwing an Ohmmu in “pre-emptively” to preclude being stuck with no vehicle and no warning other than “your car is dead replace 12 V” and all that that goat rope involves trying to get service from Mobile OR a 100 mile drive EACH WAY to the nearest SC after an apparent 2-3 week appointment via the app. Also,toying with throwing a battery monitor on with app notifications but not sure how much warning THAT will even give me.

Ski
I personally wouldn’t get the ohmmu until they solve this issue while it isn’t that bad who knows if they might have to change something on the battery
 
I got a 12v battery tester (the kind that sits in the socket not attaches to the battery), and when the car is off and it's on 12v battery power it steadily shows 13.07v-13.08v, shows a full battery, and certifies the battery as "good". When I turn the 3 on it "drops" to 13.01v-13.04v, flips to charging mode, shows only two battery bars (low), and certifies the battery as "bad". Turn the car back off and it goes back to good. So to me, assuming the test results are accurate, this shows it could be some kind of calibration issue when charging the battery. It'd be great if some of you that don't have the issue could do a similar test.

HW2.5 and have had the issue through the last two updates.

https://www.amazon.com/gp/product/B000EVWDU0
 
Last edited:
the ohmmu battery is fine. i get 13.x volts constantly.

i have a module connected to the battery that has a phone app and I see the charge whilst im in bluetooth range. ive had the battery since april this year and got the error on the 28.6 update. every day i check the battery, even whilst driving, and the voltage is a constant 13.x. when the battery needs charging the app shows this.

tesla implemented some new battery test system to catch faulty conventional batteries early and it does not like the info it gets back from the ohmmu battery. the data the ohmmu battery gives back is not what model 3 expects, so it still does a few more tests. after X tests, model 3 gives up and says "i guess this battery is going bad" and alerts you.

i can understand with all the 12v threads and model 3 being an electric car, it can instill fear in those who dont have the ohmmu.

i have complete faith the battery is solid and the charging system is still doing its job. no one who has this battery with the error has stated they got stranded. there are even a couple of cats on here who DONT have the error, so that data to me tells me this battery can be counted on.

When I turn the 3 on it "drops" to 13.01v-13.04v, flips to charging mode, shows only two battery bars (low), and certifies the battery as "bad". Turn the car back off and it goes back to good. So to me, assuming the test results are accurate, this shows it could be some kind of calibration issue when charging the battery. It'd be great if some of you that don't have the issue could do a similar test.


i dont use a cig lighter thingy, i have a module directly attached to the ohmmu battery. when i "turn on" model 3, there is no fluctuation in the battery at all and certainly not what you are describing here.
 
Likewise, Ohmmu installs first week April 2019, still no error codes, currently on 2020.32.3 and took the Model 3 SR+ out for a ride today and no error codes. March 2019 build HW2.5 newly installed Auto Pilot when it came out for $2,000

Here’s a picture of the last time I checked the 12 Volts on the Ohmmu. April 21st.

AF7D44AF-2759-4C17-A6AD-2081523EF83B.jpeg