Montana Owners Club - Keystone Montana 5th Wheel Forum - View Single Post

Joint Venture II · 03-15-2023, 12:46 PM

I replaced the OEM single group 27 battery that was original and installed 3 Interstate group 24 SRM Deep Cycle RV batteries at 81AH each for a total of 243AH. Your Interstate 27M EFB battery @ 90AH which if plugged into power and a charger will suffice for camping. Because lead acid batteries only permit about 50% discharge I doubt you could run your furnace for long without charging the battery. My 3 24's were replaced with a lithium 8D @ 270 AH's because they would drop to 50% charge overnight in cold weather due to furnace running a lot to keep inside temps to 68-70*.

Your choice of a single Interstate 27M EFB battery will be a good replacement for the OEM battery but has limits.

03-15-2023, 12:46 PM	#7
Joint Venture II Montana Fan Join Date: Mar 2022 Location: LYNDEN Posts: 286 M.O.C. #30751	I replaced the OEM single group 27 battery that was original and installed 3 Interstate group 24 SRM Deep Cycle RV batteries at 81AH each for a total of 243AH. Your Interstate 27M EFB battery @ 90AH which if plugged into power and a charger will suffice for camping. Because lead acid batteries only permit about 50% discharge I doubt you could run your furnace for long without charging the battery. My 3 24's were replaced with a lithium 8D @ 270 AH's because they would drop to 50% charge overnight in cold weather due to furnace running a lot to keep inside temps to 68-70*. Your choice of a single Interstate 27M EFB battery will be a good replacement for the OEM battery but has limits. __________________ 2003 Holiday Rambler Navigator 43PKD 500HP 11L Cummins ISM 2005 Keystone Montana 2955RL (sold) 1999 F350 SC (sold)