How to tell if its AGM battery

[c63chris]

I have a 2009 SL63 with two batteries. Have bought a charger to keep the consumer battery going in the winter as the car won't be used much. It has an AGM mode. I know what that is ie a type of battery but the user manual doesn't say if it is and the label on the battery just says 75Ah and a Mercedes part number.

 

[alabbasi]

It will say AGM instead of lead acid.

 

[andy27168]

Hi,
Post the Pt. No. and I will look in the EPC to find out whether its a AGM or Lead Acid.
Mercedes referred to its AGM Batteries as "Fleece Technology", some cars Mercedes have changed from AGM Batteries to normal Lead Acid. For instance my CLS55 Came from Factory with a AGM Battery now Mercedes state to use a Lead Acid one, this is almost certainly the case for other models too.

 

[190]

Fully charge the battery (and you can do that safely in non AGM mode) then measure the voltage after an overnight rest. If it's in the region of 12.6 -12.7 volts then it's a normal lead acid battery. If it's in the region of 12.9 volts or higher it's an AGM lead acid battery.

The AGM option on the charger will provide a slightly higher charge voltage which shouldn't be used long term on a normal battery but it won't cause instant damage.

I've never seen an AGM battery that didn't say AGM on it an if MB have supplied an AGM battery without a label then that's dumb in the extreme.

 

[Tones]

Another way to know is if you have stop/start it will usually be a AGM battery. Newer Merc's now have 2 batteries now like my new Vito 116 bluetec auto. Hope that helps.
If you have a CTec charger then do not charge the battery in the car in the AGM mode or recon mode unless the battery is disconnected as the higher charge voltages can damage kit in the car if it is an ordinary lead acid battery fitted. They do say to remove the battery connections to the car for the recon mode. The intelligent CTEC charger is a brilliant bit of kit.

 

[c63chris]

Thanks for the replies everyone. It looks lead acid. Took a photo of it. Hopefully attached with the part no. Have been using the CTek in just normal mode as I find after a couple of weeks the car doesn't want to know. Seems everything shuts down. With the charger on the keyless go still works and the car seems happy.

 

[c63chris]

Another way to know is if you have stop/start it will usually be a AGM battery. Newer Merc's now have 2 batteries now like my new Vito 116 bluetec auto. Hope that helps. If you have a CTec charger then do not charge the battery in the car in the AGM mode or recon mode unless the battery is disconnected as the higher charge voltages can damage kit in the car if it is an ordinary lead acid battery fitted. They do say to remove the battery connections to the car for the recon mode. The intelligent CTEC charger is a brilliant bit of kit.

Thanks that's true but this model ofSL comes with 2 batteries without having stop start. cTek does seem to work well. Plug it in and leave it