Mercedes-Benz Forum banner

Batteries & charging

2K views 5 replies 5 participants last post by  VitalSpark 
#1 ·
My wife has 2006 SL500. It has under the hood the starter battery & in the trunk the 'convenience' battery. The car doesn't move all winter so I have been searching the forum & find I know little about some of the terms. What's AGM or Gel filled? Well I can guess what gel filled is but how do you tell if the battery is gel filled?
I suppose I really only need to know what float charger between CTEK & Battery Tender since the forum members fall into either one of these camps.
One last question, does the front battery ONLY start the car nothing else. Reception engineer at dealer frankly wasn't too sure!
 
#2 ·
Gel filled? That is a high end battery, Gel filled used to be reserved for Marine Battery's because of the inheritant nature of being in the Ocean.
Good to see your MB has this.
I HIGHLY RECOMMEND Battery Tender. I have the BT for my Motorcycle and has saved me hundreds of dollars. I also installed ( I have a 2000 model ) a Battery Tender for my C230 and it works interchangedly.
Super easy to use and BT monitors your battery. It removes sulfates.(?)
Your owners Manual will tell you which is your primary battery. It's there, trust me, you might have skipped over it.
 
#6 ·
Thnx

Thnx everyone for replies. I have had a long talk with the dealers electrics tech & it might be of more than passing interest what he says. I might get bits wrong it was a long conversation!
Basically the batteries are linked so whilst we consider the hood battery will draw main starting current if its not up to it the battery management takes over & uses both. The idea is that so you can always start the car using the key for entry then in the dash even when the batteries are low thereby not being stranded.
There are 4 SAM's, one alternator & the regulator/manager decides everything regarding charging & use. When one of the batteries goes faulty depending on the fault the alternator can produce overvoltage trying to 'manage' the system resulting in a blown SAM usually.
The alternator is not available new, only remanufactured by Bosch.
Now there may be someone out there with other ideas but it all seems to make sense.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top