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I monitored the 12v battery voltage during an OTA update
- Thread starter scottf200
- Start date
We expect a full report of the findings and a picture of your new charging profile
AlanSubie4Life
Efficiency Obsessed Member
We expect a full report of the findings and a picture of your new charging profile
Yeah. Only if they do it free of charge. Though I will get a battery from them myself and put it in myself shortly, if they insist on charging me. Just do not want to pay the labor.
THX723
Member
Good luck!
I find that it generally takes ~2hr. of inactivity for my car to go back to sleep. I can only guess if the 12v battery needed more tending, it would extend that out (does an insomniac Tesla imply potentially dying 12v battery?)
THX723
Member
Adding my data points (2018 Model 3). Car has been unplugged. Looks similar to @power.saver.
My battery was recently replaced by Tesla during the FSD retrofit in late April. Tech said the "12V Battery Needs Service" warning was shown while the car was in their possession, which came as a surprise to me. I have never seen that warning nor experienced any issues up to that point. Glad that's now out of the way.
So the DC-DC converter was actively 'pumping' up the 12v (14.35v) ... then the dip during parts of the OTA being applied and the 12v battery was on its own (dipped to 12.8v). The DC-DC converter is off during parts of the OTA since its software management wouldn't be running (i.e. during applying the related software components or the reboot). After the update, it boosts the 12v battery up again (14.35v). That is the way it 'feels' to me at least.
AlanSubie4Life
Efficiency Obsessed Member
L M A O ! ! !
I don’t even drive my car these days; I’m not even sure why I care. I guess this is for science.
Should be pretty definitive if it cleans things up though.
THX723
Member
I would think the DC-DC converter is still working away during sw installation. The 1st dip likely occurred at system reboot post installation (when you hear those contactors going off).
It would depend on what components (software dependencies) of the software they were updating and if that component was integral to the Tesla DC-DC converter software. You can't run the software for DC-DC converter if you are updating parts (all) of that software 'subsystem'! -- So this would vary by what each OTA did, of course.
AlanSubie4Life
Efficiency Obsessed Member
We expect a full report of the findings and a picture of your new charging profile
As alluded to, we'll have to wait a little longer. Tesla would not do a warranty replacement while Mobile Service was out. Tesla recommended I disconnect 3rd party apps (I did already try this, but did not change the password, just logged out; however, I forgot I had ABRP connected still, so who knows what it was doing). So I've redone my password and we will see; only the Tesla app can connect now.
We'll see what happens. I actually think it's possible this could have been the issue - it just is hard to understand how this could be a battery issue with the way it is behaving. I guess I'd give it even odds.
Maybe next week I'll have resolution. I do think that I'll probably go pick up a Tesla battery even if it starts looking fine - just to have it ready to go. Relatively cheap insurance.
It doesn't appear there is any need to do any of the underseat disconnect procedure for a 12V battery replacement; the Mobile Service did not bother with that. Though he did have a battery charger as well, to give it a boost while he was working on software updates. In any case, it should be pretty easy to replace.
It will be interesting to know if ABRP was pinging your car all that time. I don't use any 3rd party apps, never know what they might be up to.
I installed 2020.40.8 last night at 1:20am. Seemed to go fine except my car was left in 'boosting' 12v DC-DC state of 14.3v. I noticed on my Tesla screen that I was not connected to wi-fi so I rebooted (unrelated). Then I saw, by chance, that my DC-DC dropped back down to the normal 13.3v.
https://i.imgur.com/hJkI1xV.jpg
https://i.imgur.com/hJkI1xV.jpg
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Finally installed. 2018 model 3 with a week old 12v battery.
AlanSubie4Life
Efficiency Obsessed Member
Since my HW3 installation (and a reminder, disengagement of 3rd party apps), the neural nets in the FSD computer are apparently working overtime to determine the status of my battery.
Lots of time spent at 14.1-14.16V, which is brand new! A lot of time spent awake (it was fiddling around with downloading an update yesterday). Seems like it might be settling down now; will see whether it gets into a rhythm.
I am suspecting the third party apps (I suspect ABRP which I had not used in months, since I had already tried disabling Stats) were waking it every hour, but we will see. @brkaus to me it looks possible TeslaFi is disturbing your car as well. Wouldn’t change anything for a few days so you can establish a baseline...then you could try disabling it for a day or two if you happen to be leaving the car sitting for that time. Before then, I expect to have a better idea of whether that was my issue.
FSD install, of course, is where the monitor drops out for a few hours.
Lots of time spent at 14.1-14.16V, which is brand new! A lot of time spent awake (it was fiddling around with downloading an update yesterday). Seems like it might be settling down now; will see whether it gets into a rhythm.
I am suspecting the third party apps (I suspect ABRP which I had not used in months, since I had already tried disabling Stats) were waking it every hour, but we will see. @brkaus to me it looks possible TeslaFi is disturbing your car as well. Wouldn’t change anything for a few days so you can establish a baseline...then you could try disabling it for a day or two if you happen to be leaving the car sitting for that time. Before then, I expect to have a better idea of whether that was my issue.
FSD install, of course, is where the monitor drops out for a few hours.
@AlanSubie4Life i suspect teslafi is keeping it awake longer, but I do not think it can be the cause of the wake ups. This is something I will be watching.
why did yours drop to 9v? That looks like a problem to me. What is the voltage across the battery when it’s disconnected from the car? There is no way it should drop that sharp to 9v
why did yours drop to 9v? That looks like a problem to me. What is the voltage across the battery when it’s disconnected from the car? There is no way it should drop that sharp to 9v
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THX723
Member
FYI, I too have Teslafi and my car has no issue falling asleep.
Adding - mine has slept since early evening last night. With teslafi still running.
AlanSubie4Life
Efficiency Obsessed Member
The 12V and the monitor were disconnected during the HW3 install. Negative terminal of both devices was disconnected. These readings do not represent the open circuit battery voltage. They are not readings - just missing data.
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