I'm tired of dealing with the lousy factory battery in my 21 and I haven't had any luck getting the dealer to replace it even though they acknowledge their problematic. Since the truck does sit occasionally when I travel I want to go with the highest capacity battery I can. It looks to me I can fit a H8 battery in the tray, has anyone replaced the factory battery with a size H8 battery?

 

I don't know about the size, but I put an Odyssey AGM battery in my Jeep and it's been a champ. I'll replace the factory battery with one when the time comes.

 

Is it still sitting around as you drive the company car? There’s definitely so much going on with these trucks that they it only takes a few days for the systems to go into deep sleep.
I had a shop tell me the battery in wife’s car was bad. She doesn’t drive often enough or far enough.
I test the battery’s myself. It’s fine.

 

Just remember to reprogram the BMS Battery Monitoring System to show the heavier battery and that it's a new battery or the system will never charge it up to it's full potential.

 

I have the original H6 battery, 25 months old. I too would like to know about suggestions to replace with a quality, better (bigger?) battery.

 

Doesn’t BMS monitor and charge to a voltage potential? A larger battery would have a higher reserve capacity at the same nominal voltage capacity, which is what the OP is really after. In that case, no BMS adjustment is needed. Am I missing something?

 

The amount of batteries needlessly replaced is amazing. Charge battery, then load test it. It will likely pass. The issue is lack of driving. The truck requires you to drive it more than 30 minutes to charge the battery adequately and not let it sit for days and day, or weeks. Or, buy a Battery Tender Plus, and never have an issue again.

This has been this way for years, I put a Battery Tender in my 2013 in 2014, never had an issue until 2021 when it finally did fail.

 

If his 2021 battery has diminished in max voltage/capacity, the bms adjusts accordingly so as not to overcharge the existing battery. Resetting will reacquaint the bms with the new fully charged battery votage/capacity baseline. Easy to do. Search "reset bms"

Great affordable product. Avoid starting truck while connected.

 

Good point. Actually, won't hurt, but if you try to drive away while connected...

I have a sign on my front seat - "UNPLUG TRUCK". Sign comes out, truck gets unplugged, reverse when get home.

 

LOL, what I meant was starting the vehicle for servicing and such while connected, not driving away. I did that often with my motorcycles in the off season only to cause the Deltran to fail, overcharging and destroying my battery. They gave me a new charger but obviously not the new agm battery.