Prerna

Bought a new battery 2 years ago, left the car untouched for 11 months as I was abroad. When I came back, the battery was totally dead, so I charged it for many days. It works but the dashboard shows the battery sign, and it sounds weak when I crank. Is it normal and is there any way to make that battery good again?

Plutoe

Batteries like to be used or at least be disconnect while away for long periods.

efzauner

yup even AGMs like to stay charged... you should have put a trickle charger on it.

Prerna

Too bad, I guess there's no way to make it good again

By the way is it necessary to put an AGM battery or a regular one can do?

efzauner

This battery is inside the passenger compartment. You don't want acid spills or fuming. Be smart.

OR-CLK350

My original battery had to be replaced after 10 years in service, and I decided to buy an OE replacement (@ $167 MBZ dealer)... I changed it Dec 2016 and haven’t had any issues. I’m very happy w/OE but are sure there are cheaper aftermarket options you can chose from.

halcut

I need to get battery replaced too. Which one is recommended for 2012 R350? Thanks in advance.

efzauner

My 2005 C240 battery was still good after like 12 years.
I was having electrical issues with my 2011 R350 so I put in a new AGM from our local Canadian Tire, cost about C$200 and put the R battery into the C. All same size.
Ended up being the alternator. These batteries do last a long time.

Prerna

Was your alternator not charging at all, or was it charging in a way that it killed the battery rapidly?

efzauner

The battery was OK still, it did not need replacement but it was the first thing that I did. The reason is that if I charged the battery over night I was able to start the car and run. So I though it was the battery.
I was lucky enough to get it working to drive it to my fav garage 50 km away in Montreal.
It was the regulator, overvoltage the mechanic said. Got all sorts of error messages from cannot shift transmission to SRS failure to ABS failure etc. Seeems various modules just shut off when they see bad voltage.