maximus16v

Hi Guys

Just bought an E55 AMG and some mornings I am getting the "battery low convenience features have been disabled" message. Some times the next morning other times not for a few days. Dealer said when I bought it that it was aux battery so I ordered one from Mercedes. I was just thinking could that also be the main battery? Or is that message always an aux battery thing? Just want to make sure as I don't want to end up replacing the wrong one!

rapidoxidation

you can have either or both batteries load tested to find out which one is causing an issue.

screw991le

On an 01' just have them both changed with AGM batteries and get it over with. IMHO

maximus16v

oops forgot to change my car lol. I have an 05 E55 now. The 01 S is long gone!

Toadster

check the parts thread - they're < $70 for the aux battery, the main battery can be had for < $160 at discount stores like Costco/WalMart

but make sure your charging system is working well

welcome to the fray

Rocman8

That message is not related to the aux battery

maximus16v

Ya that's what I thought. They had told me when I bought it that it was just the aux battery (said if it was main batt would be red battery symbol in dash) probably because the aux battery was cheaper then the main. I was thinking of keeping it Mercedes parts only so didn't mind the $150 if it was in fact that. But maybe I'll get the aftermarket ones and change both out if necessary.

My fear is it is actually the charging system. Last night I took it for a spin and the message went away after 15 mins. When I stopped for gas half hour later and started it up again the message came back.

Rocman8

If the message goes away then your charging system is probably ok. The battery probably just can't hold a charge. Check the date codes. Aux batter has it printed on top and main batter should be stamped on the negative post.

StarvingArtist

A bad main battery puts a huge load on the alternator. Change it soon. I got an oem main battery from the dealer for $160 cash and carry.

Rocman8

You just got a regular wet battery and not an agm battery? Is the casing white or black?

Toadster

AGM batteries at SAMs club are < $160

Rocman8

I get that but he said at a dealer

StarvingArtist

AGM. Black, identical to the original. The first one lasted 9 years, so I figured I had better get another one no matter what it costs. The price was a pleasant surprise.

Rocman8

ahh very nice!