22 Palatium #3.5 25K miles 31/2 years old. Is one its 3rd battery H6 under warranty. Current battery is going bad. Dealer tells me H6 is only battery that will fit. Will H 8 fit have seen several u tube says yes. Think I'll get an everstart.

 

My understanding is that H7 will fit in all, and that H8 will fit in all but some will need to put some electronic components on top as opposed to next to the battery because of the increase in size. The best recommendation is to use Forscan and change the charging parameters to 90 or even 95% on the battery BMS in order to save the battery. It's not just a battery size issue it's a programming issue and many modern vehicles struggle when it's not driven "enough". The H6 in my 2021 is still fine but I drive a lot. Cheers

 

I replaced my OEM H6 battery from my 2022 XLT (19k miles) in Oct. Went with a Walmart battery H7. Love it.

 

2021 F150 3.5
I recently put in a H8 with no issues fits battery tray well and wires reach. The insulation from the original H6 doesn't fit around the battery.

 

oddly we also have a frontier in the family whose battery again failed and out of warranty,, dealer wanted $480.00 plus a hour, it now has a everstart h7 agm that cost $189.00 ,no issues,