12V Battery Replacement Cost

[supersnoop]

I paid about 350 euro's for an Audi A6 battery. That is about 410 USD. The explanation behind this ridiculous pricing was that it the car needs to relearn/pair the battery or whatever bad excuse they had.

This kind of thing is why dealer service centers have a reputation for being frauds.

My 760Li absolutely had a function in the dealer programming tools to reset and learn the capacity when the battery is replaced. Without the programming, strange electrical demons reek havoc throughout the car.

That cost is about right for a high capacity AGM battery and an hour of dealer service.

 

[rudholm]

My 760Li absolutely had a function in the dealer programming tools to reset and learn the capacity when the battery is replaced. Without the programming, strange electrical demons reek havoc throughout the car.

That cost is about right for a high capacity AGM battery and an hour of dealer service.

So, what does the car do with this information? And what happens as the battery ages (or it loses water through electrolysis) and the capacity falls? If the car can track that change, why can't it learn a new battery without help? Granted, it's been thirty years since I was a member of the SAE, but this sounds like car sales hand-waving to me.

EDIT: Oh wait, perhaps we're talking about the ECU re-learning all its parameters? Those usually get blanked out when the battery is disconnected and until the ECU gets itself sorted out, the car will run like crap.

 

[dhrivnak]

Another nice advantage of a 1.5. No 12v to ever mess with.

 

[jfischer]

My understanding is that they replace the 12V battery as part of the annual maintenance.

No they dont replace the AUX 12V battery. The only batteries on the roadster they replace are the keyfob batteries.

 

[Jonathan Blow]

My 12v battery is dying (I can't lock the car any more)...
Does anyone know somewhere in the Bay Area that I can just take the car and they won't get weirded out by the fact that it's a Roadster, and they'll just replace the battery? I am not worried that much about minimizing cost, I just want to get the work done. I am getting super frustrated with Tesla service -- they seemingly don't want to deal with Roadsters any more (I mean, I understand why, but it's hard for me), they just ignore support emails, don't call me back for weeks, and so forth.

 

[gregd]

If the car is awake, the 12v battery shouldn't be required for anything, including the locks. You might have something else going on. Was there an alert specifically calling out the 12v battery needing replacement?

I presume you've checked the battery in the key fob.

And, yes, Tesla service can be exceedingly annoying for Roadster owners. Don't get me started...

 

[Jonathan Blow]

Yes, I am getting the 12v Battery Insufficient Charge error every time I start the car.

It seems very clear that the 12v is used for actuating the door handles and locks. When I go up and press the door handles now, it often takes about 3 seconds for them to sluggishly do their thing.

The fob battery isn't dead; I can open the trunk with it just fine. I just can't lock the car. Which, in the Bay Area, is a pretty bad thing these days!

 

[gregd]

Yes, I am getting the 12v Battery Insufficient Charge error every time I start the car.

It seems very clear that the 12v is used for actuating the door handles and locks. When I go up and press the door handles now, it often takes about 3 seconds for them to sluggishly do their thing.

The fob battery isn't dead; I can open the trunk with it just fine. I just can't lock the car. Which, in the Bay Area, is a pretty bad thing these days!

If you have a volt meter, perhaps as a sanity test, you might take a reading from the accessory outlet with the car awake (it will be zero when asleep), and see what it says. Mine reads about 13.4v. Be VERY careful not to short out the connector with the meter's leads.

Separately, if/when you get the battery replaced, I found it handy to bring a pair of wires up from the battery terminals to a connector accessible with the front grill open, but protected from weather. I used a regular "Power Pole" unit, but anything suitably covered so it won't short against other stuff will do. From there I can monitor the battery's voltage directly without taking the car apart. 13.77v seen there, pretty much universally (car awake or asleep). I should also be able to "jump" the battery if needed, but have not done so as yet.

 

[Tozz]

If the car is awake, the 12v battery shouldn't be required for anything, including the locks. You might have something else going on. Was there an alert specifically calling out the 12v battery needing replacement?

Ehm, no. That is not correct. The 12V battery powers everything in the car excluding the motors. If you would disconnect the 12V battery, even when the car is awake, the car will shut down due to lack of power.

The on board computer will activate the onboard DC-DC charger (to charge the 12V battery from the HV-pack), but that thing is not constantly on. Only when the 12V voltage drops below the threshold.

 

[X.l.r.8]

Ehm, no. That is not correct. The 12V battery powers everything in the car excluding the motors. If you would disconnect the 12V battery, even when the car is awake, the car will shut down due to lack of power.

The on board computer will activate the onboard DC-DC charger (to charge the 12V battery from the HV-pack), but that thing is not constantly on. Only when the 12V voltage drops below the threshold.

I don't like to use the dislike button as it seems personal, however many of the owners in the ROADSTER section have run without even having the 12v battery connected. It seems that what may seem like prudent advice on one model may not transfer well to other models

 

[Tozz]

I don't like to use the dislike button as it seems personal, however many of the owners in the ROADSTER section have run without even having the 12v battery connected. It seems that what may seem like prudent advice on one model may not transfer well to other models

Hmm, I stand corrected. Somehow I thought this was about the Model 3. My bad.