GOLDSc300

I would say AMG batteries are not much more expensive. Needless to say that my next battery for the SC will be AMG. Thanks for the good suggestions. The comment about a special AMG charger is an interesting one. I will google it. Also AZ summer is a way more hotter compare to CA and just for that reason AZ batteries are not last longer than 3-4 years.

Bgw70

I know what you guys mean but Mercedes Benz builds the AMG...the battery is an AGM.

I am not trying to be sarcastic or rude...

Wilson2000

So many acronyms, so little brain cells left! Thanks for the catching this before it got further out of hand!

GOLDSc300

Sure, the battery is an AGM. Thank you for pointing out. Btw, AGM batteries do NOT require a special charger.

Wilson2000

One of my AGM's went completely dead, and would not take a charge from several of my battery chargers. I took it to where I bought it and they were able to charge it over night with their AGM charger. I've heard of this phenomenon from multiple sources since then.

Caflashbob

The sc is not made to charge an AGM correctly. Slightly higher voltage than agm’s like. That being said I have an AGM and a smart temp compensating battery tender charger as I drive the car rarely.

DshngDaryl

I think it may apply to all batteries though. Modern chargers won't charge a battery when the voltage gets too low. It essentially doesn't see the battery. I saw SAMCRAC on youtube hook his dead battery to his car battery and then the charging cables to his bad battery. This gave the charger enough reading to start the charging process.(I don't know if I would do that, but he claims to do it all the time)

If you have an old, dumb charger. You can just hook it up to the battery and it will charge without checking.

I also heard somewhere that if you trickle charge a battery that has been sitting for awhile, you might be able to revive it. It has to do with the trickle charge (12 hour) cleaning off the lead plates or something, whereas a quick charge (1 hour) doesn't do that.

Wilson2000

Thanks DD...all good information! In my case, I tried two different modern chargers and one specifically noted that it worked on AGM's. I even tried the trickle setting overnight. Then, I tried my big-old-toaster-sized charger that I have been using for 45 years. None did the trick, before returning to the AGM dealer for a charge. However, I still haven't seen enough evidence for a dedicated AGM charger to make me go out and spend $130 for a fourth charger! I would almost prefer to switch back to wet-cell technology as opposed to adapting to the quirks of AGM's, especially after hearing in an earlier post that the charging voltage of the SC is too high for AGM's.

DshngDaryl

Take a look at this PDF and tell me if I am reading it right. I had no idea that there was an optimal charging voltage for a battery, but now that I think of it, that makes total sense. According tot his PDF, it seems like our alternators put out 14.4 volts, which is .2 volts too little for the optimal charge.
https://www.centurybatteries.com.au/...y-charging.pdf

Is that how you read it?