Paul-2018AMG

About 3 hours after a short trip to the supermarket - went to the garage to take the AMG on another short trip. All headlights and tail lights were on - vehicle not running. Could not turn off any lights. FOB did not turn on or off the car - no interior lights came on when I opened the door. Nothing - car totally locked up. I quickly changed the batteries in the 2 FOB's - didn't help. Tried to start the car with the FOB remotely - tried sticking it in the key slot - nothing. Depressed the brake - you can tell nothing is working - no travel in the brake pedal. The Vehicle batteries are both changed out 2 months ago. I have the trickle charger going - doesn't seem to charge. Door lights will still not turn on when I open the door. Vehicle is brain dead - think it must be something to do with the computer - anyone else had any sort of issue like this? Car has been fantastic until Friday evening.....Car has 67,000 miles - did all the service at Mercedes - never an issue other than tires wearing out quickly....

sub786sub

Sometimes, a new battery can be just a bad apple. It happened to me but with my Lexus. I swapped to the new battery and it died just after two days. Was not able to recharge and no short circuit was found and all fuses including main relays were intact. It also locked itself (poor battery volts will not let locks work with the remote key). After changing to another new one (2nd new one in a week) it worked. With my GLE I was not able to recharge and the vehicle locked up, but the new battery fixed the issue. So I suggest jumpstarting it if that works then definitely you have the bad apple (battery).
I remember I spent 2 days figuring out all other possible options after changing to a new battery and never thought that a new battery could become bad. Then I checked with the voltmeter, connected directly to the battery terminals (Disconnected from the terminal) it was dead like 0 volts. Even a dead battery has some volts. I think the plates inside or the connection inside of the battery were short-circuited. So get a multimeter ( it is cheap 10 bucks from Harbor freight) and connect directly to the +ive and -ive terminals after removing the connectors. See what you get

chassis

Please post codes.

Paul-2018AMG

Thanks for all the replies and help from everyone. I called MB Roadside Assistance early Monday morning - they sent out a battery jump first - I thought I would need a tow. Battery Jump worked and drove the car to Mercedes dealership. After about 2.5 hours they told me they needed to replace the battery before they could continue to check for internal computer errors. I told them I had replaced the battery in late September (thought I replaced in Dec). MB wanted $800 to replace the battery. I called the shop that put the batteries in - in September. They told me to bring the car in for them to check. I decided to do that - had Mercedes get my car running again - and drove to the other shop. Yep - that was it - new (in late September) battery was shot....caused all those unusual errors - lights on - couldn't turn them off - nothing inside the vehicle worked - dash or anything. That shop ran the computer check - said everything else was fine. Car started - no problem - seems fine. Again - thanks to everyone for their insightful comments - this was my first post on MBWorld.......

kajtek1

Good to hear the car is running again.
Electronics don't like low voltage and over the years I ended with 3 battery testers beside multimeters.
Testing battery is tricky, as you are measuring electrical output to determinate chemical reactions inside, but beside load tester, I have Solar tester, who using electronic gizmo is checking CA.
Unfortunately there is lot of problems with new-era AGM batteries. Even theoretically they suppose to last longer, they don't
The 100 months battery warranties are history.