Xattica

Hi,
Is time to change the OEM Aux Bat. Panel has the ugly red message. I have been reading about the replacement. But don't have the final answer.
Do I need to disconnect the negative from the main bat? Or I can just replace the aux battery?

Thanks.

211.070

It is not necessary to disconnect the main battery during the AUX battery replacement.

James M

You don't need to touch the main battery, just whip the aux out and replace.
Before you replace the aux, I suggest you either go to a battery shop and have them check that it is not your alternator or voltage regulator. If you have a multimeter then just check it yourself. The aux battery should give a reading of 12V or slightly more when disconnected from the car, if the reading is around 10.5V, then chances are it is your aux battery. When connected to your car with the engine running, the aux battery should read around 14.4V, if not then you may have alternator issues.

gmphertford

When you have replaced the battery u may have to clear faults codes to get rid of red light off dash. Check alternator after to make sure charging.

novae500

See that this is an 05 and if the aux battery hasnt been changed, it would be a good time to change it now.

Xattica

Thanks a lot!
Tomorrow I will check the whole system! I have been reading about get the Aux bat on autozone or pep boys. Any recommendation?

Thanks again.

Toadster

check the parts thread -pretty cheap < $70 online shipped

400RWHP

^This.
I bought a battery from Chrome Battery on Ebay for $39 shipped that has worked flawlessly for the last 2 years. Great warranty and great customer service too.


Regards

ArmoE55

How difficult is it to replace the Aux battery? With simple tools, is it a DIY?

To be honest, I don't even know where it's located under the hood hahaha. Is it under a cover?

Toadster

very easy - with basic tools, it's under the passenger side filter cover - one simple nut to access that

http://e55-amg.blogspot.com/2013/03/...t-ordered.html

moosejaw

i think one guy claimed he used some salad tongs to remove his.