Low voltage battery

[Prusljix]

Hey,
I got this issue with low voltage battery:
I got my car with VARTA 12v battery and its dead. Its longs about 3-4 month in summer and about 3-6 weeks in winter. I bought new battery (2 times now), but my Model 3 dont charge it. Its last about 1 week from full to empty and I need to change/charge it. Do I need it to programme something or whats can be the problem?

 

[Soul Surfer]

Hello,
I believe you may be translating to English, so some intention may have been missed. Can you share with us the model and year? Is there any warranty left? Any addition information, will make it easier for us to assist you.

 

[Prusljix]

Hello,
I believe you may be translating to English, so some intention may have been missed. Can you share with us the model and year? Is there any warranty left? Any addition information, will make it easier for us to assist you.

Hey. Its Model 3 SRP 2020. Warranty till 18.12.2024. But the nearest Tesla service center is about 700km away from me, so its a little problem there.
Maybe I can take some photos from service mode with voltages, but i dont see there other problem.

 

[GtiMart]

You fully charge the new 12V before putting it in the car?

 

[Prusljix]

You fully charge the new 12V before putting it in the car?

Yes

 

[Soul Surfer]

Hey. Its Model 3 SRP 2020. Warranty till 18.12.2024. But the nearest Tesla service center is about 700km away from me, so its a little problem there.
Maybe I can take some photos from service mode with voltages, but i dont see there other problem.

Do they have mobile tech service?

 

[Flybyglass]

I agree with the service mode suggestion. Open service mode (not the service menu on the mail screen) and check for notifications that are usually more detailed.

 

[GtiMart]

Do you have anything else plugged on the 12V circuit, maybe directly on the battery? I believe the car counts the energy it pulls from the battery and has some kind of limit of what it will charge.

 

[Prusljix]

Do you have anything else plugged on the 12V circuit, maybe directly on the battery? I believe the car counts the energy it pulls from the battery and has some kind of limit of what it will charge.

As i know, there are nothing.

 

[Prusljix]

The biggest concren is that the Old (dead) battery long much more than the new (the same model) accu.

 

[Prusljix]

Today i change the battery: before and after. The inserted battery is one week used before and charged full again.

 

[Flybyglass]

Today i change the battery: before and after. The inserted battery is one week used before and charged full again.

If the same battery as previously reinstalled, I would consider replacing it. Based on the images it appears working normally. What I have observed is on a battery installation, the car will charge for about 6 hours then slowly settle down to a trickle until the next wakeup. Upon wakeup, about 25 amps is drawn for a moment then the car starts charging the 12 volt at 25 amps then slowly reducing until the 12 volt is fully charged and then tickle at +/- .01-.04 amps to maintain. The Varta battery shown if reading correctly is 45AH (manual says anything higher the 33ah) and 330A. The Atlas used here is 45Ah and 625 CCA. I used an AGM battery that is 41 AH/410 CCA with no issues. ANY automotive battery that is size 51R should exceed 33AH (and will probably closer to 45) and be higher than 330. Go back and look at the charging screen in service mode after 7-8 hours and watch to see if battery recharges to a trickle within a few minutes. You may want to add a module like listed below to monitor activity.

Amazon.com

 

[Rocky_H]

Do they have mobile tech service?

Tesla doesn't officially sell in Latvia, so I am pretty certain they don't provide mobile service there. This is kind of an out of market situation.

 

[Prusljix]

The situation is not good now. Since
last week, i charged my batteries 3 times. It lasts only 3 days. I think, that something is “eating” the battery. Does anyone knows a548 code?

 

[PacoPepe]

@Prusljix I'm having exactly the same issue as you with a varta battery. Did you manage to find a solution at this?

Model 3 LR RWD May '19.

 

[PacoPepe]

When the Low Voltage system service page shows the error and measures the battery at 12,6v, I do the reset unplugging the connector of the penthouse and then the LV battery page shows that the car is charging the battery at 4A until it is close to 14,4V, then the amperage is 0,4-0,2V.

So, can I discard a PCS DC converter error? the battery (1 month old) is faulty?


Thanks in advance.

 

[Flybyglass]

If you have VARTA batteries, the latest software update in service mode allows you to select what type of 12 volt battery installed Atlas or Varta. The Varta while the same as the Atlas at 45AH it is only 330CCA while the Atlas is 625CCA. I have noticed the system will periodically draw down the battery to test strength over time. Since my guess is the Varta will run down sooner, this may be the root of errors. The update and reconfiguration should correct this.

 

[PacoPepe]

If you have VARTA batteries, the latest software update in service mode allows you to select what type of 12 volt battery installed Atlas or Varta. The Varta while the same as the Atlas at 45AH it is only 330CCA while the Atlas is 625CCA. I have noticed the system will periodically draw down the battery to test strength over time. Since my guess is the Varta will run down sooner, this may be the root of errors. The update and reconfiguration should correct this.

Already tested with Varta option selected and had the same behaviour.

The error "replace the 12v battery" came after a few updates ago when the option for varta was introduced...

 

[Flybyglass]

Already tested with Varta option selected and had the same behaviour.

The error "replace the 12v battery" came after a few updates ago when the option for varta was introduced...

OK 1 things, doing the reset just to make sure close the Tesla app, power off the car using the safety screen and unplug any usb devices. Wait about 15 minutes for car to fully sleep. Disconnect the negative 12 volt terminal then the plug at the penthouse. I wait a couple minutes then reconnect penthouse then the negative terminal. Car reboots. 6 hour charge initial cycle should start over. Also, while the negative terminal is disconnected you could try a battery tester to check the Varta.

 

[PacoPepe]

OK 1 things, doing the reset just to make sure close the Tesla app, power off the car using the safety screen and unplug any usb devices. Wait about 15 minutes for car to fully sleep. Disconnect the negative 12 volt terminal then the plug at the penthouse. I wait a couple minutes then reconnect penthouse then the negative terminal. Car reboots. 6 hour charge initial cycle should start over. Also, while the negative terminal is disconnected you could try a battery tester to check the Varta.

Thanks for your reply. All steps previously done and after a week the car says "replace 12v battery".

I didn't perform the battery test because I don't have that gadget but I managed to recharge with a car battery charger and it takes sometimes only 30 minutes to charge from 12,6V to full indication and other times 1h30 (which is more normal) but I think it should need about 6-8h for a discharged 45Ah battery to go to full...

Well, this will be easier if the online shop where I bought the varta were more proactive to let me send it them for a test but they are doing all they can't do to not to do that haha.