Who Makes the Best AGM Group 34/78 Battery?

[DynoDave]

Who Makes the Best AGM Group 34/78 Battery?

I found this article through another forum (I think...if not, I'll be taking this back down!)

I don't think you can create a definitive answer here. And this article does not answer all the questions I might have (like where the batteries are made, though personal experience with EastPenn's has been good, and all I've owned have been made here). Also, some independent testing of manufacturers claimed numbers would be nice. But for what it is, I thought it was interesting reading.

Enjoy!

Who Makes the Best AGM Group 34/78 Battery?

[Tom]

 I don't know who makes the best AGM battery, but I did have my rear end kicked for awhile today....trying to charge one. 
Never had an AGM battery before

My mom recently gifted me her 1999 Grand Cherokee. I really did not want it, but she absolutely insisted.
It had been giving her fits, with an intermittent electrical issue that her regular repair shop and an electrical specialist could not find/fix.
Intermittently, all the gauges die, sometimes the check engine and air bag lights come on.
I had made one trip to TN....thought I had it fixed, but problem popped up again a week later.
She ended up buying a 2007 PT cruiser and just wanted the Jeep gone.
PT means I have a timing belt and water pump to do soon.
Not too keen on the PT, but the price was right and the mileage was low. 80k miles.
If she gets 2-3 years out of it...it will have been a good deal.
 

Anyway, I brought it (Jeep) home last weekend. Wife decided to drive it today. Lo and behold, the battery was dead.
Texted my mom....and now she tells me that if you don't start it at least every 2-3 days, that the battery gets discharged. 
Tells me it has been that way for years!
Battery is reading about 3 volts.......and my Schumacher charger (with an AGM setting) seems to charge it for a few minutes, then shut down and start flashing.
Ended up connecting my cheap jump box to the dead battery to fool the "smart" charger. Left it like that for about 30 minutes
Seems to slowly be taking a charge now, without shutting down.  
I "assume" the battery is probably capable of taking a charge since it is only a year old.

[DynoDave]

Yeah, charging these things things is a whole 'nother deal. Glad you have a charger with the proper setting. When I had Jim from Optima stop by here to answer some questions a few years ago, I believe using the proper charger, and keeping it charged, were two of the issues discussed. Of course with ANY battery, you have to use the right charger, and keep it charged.

I looked at those '90s Grand Cherokee's when James needed a first vehicle. For a 4wd Jeep ute in Michigan, they were all thousands cheaper than competitive vehicles. Didn't seem right, so I started poking around on the web. Appears these were Ma Mopars first vehicles with BCMs and heavy electrical architectures, and they were trouble makers. After reading several online stories and tech articles about repeated electrical failures, I decided to steer clear of them.

[Tom]

You probably did well by steering clear of them. As mentioned, I didn't really want this one. Used to work on them a lot at PB.
They gobble water pumps. I bet I've done at least 30 of those.
The gauges dying, check engine light, air bag light is likely going to be related to the BUSS communication.
I think I read that there were around 12 components/modules on the buss. So, figuring out the culprit may be a pain in the rear. Particularly because it is an intermittent issue. 
What should be relatively easy is finding the parasitic drain, causing the battery to almost completely discharge in 3 days. 
I did a little internet "searching" and battery drain seems to be a fairly common complaint on these vehicles.
BUT surprisingly, the fix does not appear to be particularly consistent.
My "hunch" is that whatever is causing the drain, is also likely the cause of the other electrical gremlins. 




Took about 5-6 hours to get the battery fully charged today.
Though my battery charger has an AGM setting it did not help a bit. Using a jump box to fool it into charging the battery was the trick.  
Looks like the charger wants to see a minimum of 10 volts on the battery before it decides it will charge it.  

[DynoDave]

I do keep an old time trickle charger around, because it has nothing but a 6-12V switch. If it's connected to a battery and plugged in, it's charging.

Sometimes it's nice to have equipment that doesn't try to protect you from yourself, and just does what it's told to.

[Tom]

May 23, 2017 7:01:57 GMT -5 DynoDave said:

Sometimes it's nice to have equipment that doesn't try to protect you from yourself, and just does what it's told to.

Yeah....I remember at one point, PB "upgraded" to modern battery testers/chargers.
The new equipment diagnosed almost all batteries to be bad..........and would not charge one that was significantly discharged.
After much fussing and maybe a little cussing, my service manger finally got us a cheap trickle charger from inside the store. 
 

[DynoDave]

Jim McIlvaine (OptimaJim) from Optima Batteries has posted a reply or two in this thread over at ThirdGen.org (sorry guys, it's the other 3rd gen...GM F-body). It's the thread that I got the original link in this thread from. You don't have to be a registered user there to view it.

TGO

FYI...I first approached Jim for a manufacturers point of view on a thread here. Agree or disagree, he's been a good rep. for his company, in my IMO.