I got another VCfront_a180 error overnight. My car still has not gone to sleep. I notified Ohmmu through an existing support ticket. I think I will probably switch back to my OEM 12v battery later today. Not sure what else to do at this point.
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Ohmmu 12V Battery Feedback
- Thread starter LasVegas2019
- Start date
Ohmmu has a petition to Tesla. This issue affects Model 3 and Model Y's prior to the addition of an Lion battery in later dated 3's and Y's. I'm retired and don't work for Ohmmu but do believe in the product. Here is a link to the petition.
chng.it
Can you spare a minute to help this campaign?
Let Tesla Know You Want Support for Ohmmu Batteries in Model 3 and Model Y Vehicles
chng.it
Do you have a battery charger you can put it on for a few hours? It might be worth trying.
For reasons I don't understand, that worked for me (so far). I haven't had the errors come back in about 3 months and several updates.
Have an older (V2?) Ohmmu in a Model 3. This car was previously used in a 2019 M3LR and now same battery used in a 2021 M3P for several thousand miles without issue. Prior to installing in the 2021 M3P, the battery was placed on a Li-ion compatible trickle charger. While I've kept the original 12V Lead Acid battery from the M3P (which is also on a trickle charger), have been fortunate to not encounter any issues prompting me to remove the Ohmmu. I did however sign the petition to support this. If Tesla opted to migrate to Li-ion for 12V over lead acid, they should allow customers to do the same.
When Tesla went to Li-Ion, they went NMC, not LFP, and in order to do so, they ended up with a higher voltage and had to re-do things like the wiper motors for higher voltage. They also have to manage the heat in that battery as you cannot charge Li-Ion at cold temps. This is far from a 1:1 swap on the technical side.
Keep checking the notifications menu. I never did get a flag warning but found the notifications message.
So I got the vcfront error message a couple days ago. I emailed Sean from Ohmmu customer support yesterday. Got a reply today and it seems they have a version 4(?) currently being tested which seems to hold up with no alerts for three weeks now. He hopes this will be the "final solution".
In the meantime, what do you folks do? Just continue using the car as is? Has anyone actually experienced getting stranded or any other failure by just ignoring this issue while Ohmmu works thru their solution?
In the meantime, what do you folks do? Just continue using the car as is? Has anyone actually experienced getting stranded or any other failure by just ignoring this issue while Ohmmu works thru their solution?
If the behavior of the "ghost" VCFRONT (meaning it shows up in notifications but not as a warning or advisory on the left screen) here is what the manual says:
(VCFRONT_a180)Electrical system power reducedVehicle may shut down unexpectedly
The electrical system cannot maintain the voltage required to support all vehicle features.If this alert is present while you are driving, it is possible your vehicle will shut down unexpectedly. It is also possible that your vehicle will not restart after the current drive.
If this alert is present when your vehicle is in Park or when it first wakes, it is possible your vehicle may not have adequate electrical power to start driving. A separate vehicle alert may be present to indicate that condition.
It is recommended that you eliminate or reduce your use of any nonessential features. This can help your vehicle maintain adequate electrical power for essential functions.
If this alert remains active, it is recommended that you schedule service immediately. Without service, your vehicle may not drive, may shut down unexpectedly, or may not restart.
I bolded what I think applies here. If a notification but no associated second alert then I think it OK. The systems is probably doing an overcharge test and the Ohmmu BMC is taking the 12 volt offline for a few minutes (thinking there is a charging problem). It should automatically come back online and charge. When I had this I had the "ghost" messages (would not have known if I didn't look for it) I removed the Ohmmu and it was at 95% of charge.
So i have the v3 battery and its been working flawlessly for the past two months up until yesterday. Yesterday i got out to the car after work and greeted with the vcfront_a182 error. Checked my teslax app for the 12v voltage and it was reading 13volts. I tried doing a car reboot like ohmmu says and it worked for abit but later on the error came back. Swapped back in my stock battery and all is well again. Sucks...
Active error. After i took the battery out i put it on a charger for LFP batteries and it took nearly a whole day to charge up. Now with my car lately ive been using sentry more at work since it was door dinged and thought it was done at work.
My guess is sentry is draining the battery and the HV system is not charging it up enough after sentry drains it. I havent re-installed the battery yet to test my theory and see how long the battery lasts without using sentry at work.
But i also noticed this in the tesla service manual thats now available and i think my hunch may be correct. If the car senses a voltage from the 12v at a certain range it will consider the battery failed.
"
CAUTION
Before installing the new 12V battery, make sure that the new battery's Open Circuit Voltage (OCV) is above 12.6V. If the OCV is between 12.4V and 12.6V, recharge the new battery. Any battery below 12.4V must be discarded.
Sentry doesn't draw from the 12V battery. It leaves the HV and DC-DC turned on all the time. It actually reduces load and cycling on the 12V, at the expense of 24/7 300W of draw on the HV pack.
What a weird procedure. At room temp, 12,4V OCV is about 70% SoC. They are literally telling you that any battery that is below 70% SoC must be discarded, independent of it's state of health. You're not allowed to recharge it.
Interesting, cause my issues started after using sentry more. Otherwise the battery was fine for months. Obviously correlation doesnt equal causation so maybe the battery was at a critical low discharge while i started using sentry more.
When calendar time was this? Tesla sent out a couple firmware updates in the last 6 months that change how they detect bad batteries.
My battery had an issue last week. Version was 2022.12.3.12. Now my car is on the current fsd beta firmware 2022.12.3.20
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