OK, learned something new... I never knew that the G has 2 batteries - the main (A 001-982-82-08) and an auxiliary (A 000-982-93-08) underneath the main:


Anybody had good luck charging the OEM batteries (if so, what amperage charger)? Or should I just replace it/them with a Duralast Platinum or similar? Should I replace both at the same time?

 

good to know

 

Well, I decided to just replace my main battery. Looking for a H8-AGM Group Size 49 battery, it came down to either an AutoCraft Platinum or a Duralast Platinum. Both come with a 3-year free replacement warranty:

Duralast Platinum - AutoZone

AutoCraft Platinum - Advance Auto Parts

These two batteries (along with others) are actually made by the same manufacturer. There are only really two major automotive battery manufacturers – Clarios (formerly Johnson Controls, Inc.) or Exide Technologies. The AutoCraft battery line is manufactured by Johnson Controls (Clarios), the same manufacturer as Duralast, Everstart, Optima, DieHard, and Interstate Batteries.

Deciding factor: Using the coupon code "AAPSAVES25" gets you 25% off of your purchase up to a maximum of $50, so I got $50 off my new AutoCraft battery! . I imagine that code works for any other purchases there as well.

 

Only the G's with transmissions later than the 722.6 have the auxiliary battery to provide emergency operation of the electronic shift; 722.6 and earlier equipped Gs (around 2006, I believe) do not have it.

As for the main battery, IMHO, do not screw around with anything but the MB OEM battery. I'm not a big OEM parts fan, but this is one instance where you should go OEM.

 

I hear you... sometimes the stock part is best. Turns out I already have the AAP battery in my G (ever since I bought it) and it’s lasted 6 years with no issues until recently. So I guess I’m getting another and we’ll see how that goes...

Can’t go too wrong with the 3 years free replacement warranty, but if it doesn’t last more than a couple years I’ll go back to the OEM.

interesting detail on the electronic shift.... so that’s the auxiliary’s sole purpose? Does it provide additional power for accessories as well?

 

The aux battery does power other things, but the engineering rationale for having it stems from the need to be to get the transmission into Park in the event of an electrical malfunction. This is why when the aux battery goes bad, you may see an error message that says something like "Leave engine running and shift into P" The aux battery essentially becomes the primary battery power source when the main system voltage drops too low, however, the onboard control module shuts down non-essential loads via the can-bus since capacity of the aux battery is limited. I'm not sure which loads are considered "essential", but I believe on later cars the annoying auto start/stop function is also powered by it under low system voltage conditions.

 

what year is your G? I called my dealer sometime back provided my VIN and I was told my truck has 3 batteries. So call the dealer and be sure. The video you included is G550. Mine is a G63 and was told it has 3 batteries

 

Interesting... mine's a 2012. And actually after taking out my main battery yesterday, I couldn't see another one underneath, just a solid tray with no openings. So I don't think I have 2 or even 3 batteries, unless they're located somewhere else on the truck...

If it goes by the type of transmission, the 5-speed 722.6 transmission was in the G550 up until 2006, but also carried on into the 2007-2012 G55 AMG. As of 2007, the G550 got the 7-speed 722.9 transmission (which mine has). So does that mean I should have an auxiliary battery?

 

The aux battery is used with 772.9 transmissions that are equipped with the fully electronic shift selection system which I think MB calls "Direct Select". On the G, I think that transition occurred with the 2013 model year.

 

Ahhhh.... that makes sense...
that “Direct Select” transmission is the notchless return-to-center transmission selector similar to the "Monostable Gear Shifter" in the Jeep that killed the Star Trek Ensign Chekhov dude.... so that particular type of electronically-controlled transmission required an auxiliary battery.

 

How many total batteries are in a 2016 G63 ? I thought 2 batteries then I read possibly 3.

Do they all typically lasts 4-6 years and should be replaced all at same time for convenience point of view?

Thanks

 

Please confirm how many total batteries in 2016 G63 if you happen to know.

Also share how much each and if it was OEM or other brands if possible.

Thank you!

 

Did anyone ever figure out how many batteries there are? 2 or 3?
my 2013 has a main battery and a small capacitor battery next to it. Not sure if there's another battery somewhere else

 

For 2016 G63, there are 2 batteries. My dealership will be replacing it on Friday.