Originally Posted by zimirza2003

My 2020 GLS580 (it currently has 39700 miles) is having problems: the car does not start and has to be towed to dealer for repair, they provided following reasons at various times
1) Software update fixed the issue
2) Second time the 24 volt battery terminal was painted over which caused intermittent non start
3) reprogramed the computer would fix the issue
4) I took the car in today for same non start issue, they said there is recall and checked the car computer while I was there and determined that there is battery issue
I am wondering should I claim that I have a lemon and need a replacement car?
Any suggestions, advice pleas chime in
Cheers
Zia

Originally Posted by zimirza2003

My 2020 GLS580 (it currently has 39700 miles) is having problems: the car does not start and has to be towed to dealer for repair, they provided following reasons at various times
1) Software update fixed the issue
2) Second time the 24 volt battery terminal was painted over which caused intermittent non start
3) reprogramed the computer would fix the issue
4) I took the car in today for same non start issue, they said there is recall and checked the car computer while I was there and determined that there is battery issue
I am wondering should I claim that I have a lemon and need a replacement car?
Any suggestions, advice pleas chime in
Cheers
Zia

Originally Posted by jkaetz

The 48v battery is the starter battery now. If it has an issue it will result in a no-start condition just as a failed 12v battery. Assuming it's still under warranty and you still like the vehicle, have them repair it and move on. If you're done with the car then you should pursue a replacement. You'll of course have to check your state laws for a lemon claim but you could also simply sell/trade it at this point.

Originally Posted by PJSD

In case anyone on here is wondering, my GLS has been at the dealer since May 6 (~10 days). The dealer says MBZ put "a hold" on the vehicle, to figure out the 48v battery issue. Not sure what that means. Dealer is awaiting further instructions from MBZ on how to deal with the issue. Getting kinda worried this point... They should just swap the 48v battery I would assume.

Originally Posted by streborx

This is my understanding of the long term objective -- exclusively 48 volt electrical system. But currently, cold starting still uses a conventional starter and 12 volt battery, while the auto start/stop uses the 48 volt battery and the ISG.

Originally Posted by jkaetz

There is no 12v starter anymore. The ISG is the starter. This is obvious by the way it starts. You no longer hear the starter strain against the engine compression because the ISG can apply much more torque than a 12v starter. 12v is still used for a lot of modules including the ECU as they are low current devices and don't have native 48v replacements yet. There is no way to go around the 48v system, it is just as much required as the 12v system or it wouldn't be in the vehicles.

Originally Posted by streborx

I don't think every manufacturer that has stuffed 48 volt technology into its cars is yet at this full conversion stage, although as I posted, this is my understanding of the objective. How do you jump start one of these 48 volt starter systems? Is there a 12 volt to 48 volt inverter to handle this?

Originally Posted by jkaetz

Yes the system can go from 12v -> 48v when charging. You wouldn't be able to "jump" start so much as charge the system until there was enough capacity in the 48v battery. There is also likely a 48v -> 12v path as I've noticed that if the engine shuts down via auto stop/start the system still shows ~14.8 volts instead of dropping down to the 12.5 of a fully charged 12v battery. Makes me wonder why the 12v battery is there at all if they're already doing the 48v -> 12v conversion.

Originally Posted by streborx

How large (physically and amp-hrs) is your 12V battery?

Originally Posted by jkaetz

It's still an AGM H8 rated at 95 AH just as in older vehicles. I'm guessing they know they need it for the non-48v vehicles so they just left it in place as part of the 12v system on the 48v vehicles.