Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×

Go Back   Montana Owners Club - Keystone Montana 5th Wheel Forum > MOC Technical Forums > Maintenance
Click Here to Login

Thread Tools Search this Thread Display Modes
Old 03-05-2023, 08:21 AM   #1
Montana Master
RKassl's Avatar
Join Date: May 2005
Location: Fall Creek
Posts: 1,313
M.O.C. #3699
Interstate Battery "27M EFB" Question

Time for a new deep cycle battery for the Montana. The Interstate standard 27M series came with the trailer. Interstate now has a newer upgrade 27M EFB. A few dollars more but it is a sealed battery. It is not an AGM or lithium type.

Has anyone used this newer battery in their trailer? Any issues or comments?

Bob and Nancy Kassl Fall Creek, Wisconsin
2015 Montana 3440RL Legacy Edition, G614's, Pressure Pro TPMS, Dish Tailgaters
2016 GMC Sierra Denali 3500 CC SRW, Iridium Metallic, Duramax Allison Transmission
RKassl is offline   Reply With Quote
Old 03-05-2023, 11:42 AM   #2
Montana Master
rohrmann's Avatar
Join Date: Oct 2012
Location: Box Elder
Posts: 4,272
M.O.C. #12947
It looks like the 27M is their Marine starting battery, but the 27M-EFB is their Marine/RV deep cycle one.
Bob & Becky
2012 3402RL
2012 Chevy 2500HD D/A CC 4WD
rohrmann is offline   Reply With Quote
Old 03-05-2023, 12:11 PM   #3
Montana Master
Join Date: Oct 2004
Location: Salem
Posts: 7,064
M.O.C. #2283
There is only 4 or maybe 5 battery manufacturers in it US. That battery is sold by several companies. Interstate is a good company. Look for the highest watt hours at the cheapest price from any company.
Lynwood Harrell
323 RL HC 2008 F250
mlh is online now   Reply With Quote
Old 03-15-2023, 08:42 AM   #4
Joe in Texas
Montana Fan
Join Date: Nov 2010
Location: Terrell
Posts: 351
M.O.C. #10881
It’s time for new batteries. In 2016 purchase a pair of group 24……not sure of what letters are after the. 24.
Should I stay with group 24 marine/Rv or move 27? Appreciate knowledgeable response.
Joe in Texas is offline   Reply With Quote
Old 03-15-2023, 10:01 AM   #5
Montana Master
Mikendebbie's Avatar
Join Date: Jan 2018
Location: Austin
Posts: 1,877
M.O.C. #21044
Joe - my rig came with two group 27s in a battery box. I decided to stay with group 27 because they fit the battery box that came with the unit. I googled the "difference in group 24 and 27" and found this interesting article...

...but I don't see a compelling reason for one over the other. If your group 24s have lasted 5 years that seems pretty good to me. I replaced my original group 27s at 3 years with Duracell AGMs from Sams ($199 each). We were without power for 5 days in the December 2022 ice storm (12* for several days). When the storm was in the forecast I decided to run the furnace out in the Monte at 50* because I did not winterize the Splendide washing machine. I had not counted on loosing power for five days with temps in the teens. The batteries were drained to dead and did not charge back to a comfortable level. (We were lucky - the washing machine was not damaged from the freeze) Sams does not carry Group 27 AGM any longer (they claim there was not enough demand to keep them on the shelf). I decided to go with their lead acid Duracell group 27s.

By the way - I remember you from the North Texas pop-up camping club. It's been a long time!
MikenDebbie Aggie ‘77 in the sticks near Austin TX
2019 Chevy 3500 High Country DRW
2018 Montana 3921FB
Aussie Gus + Texas Heeler Jimmy
Mikendebbie is offline   Reply With Quote
Old 03-15-2023, 10:52 AM   #6
Montana Master
432bartman's Avatar
Join Date: May 2020
Location: UPLAND
Posts: 1,107
M.O.C. #26190
I was able to fit Group 31 Duracell deep cycle AGM batteries in the battery boxes that came with my rig. So far after about a year they are doing great. I keep them unhooked when I park the rig at our storage facility.
2019 Keystone Montana 3560RL, 2020 Chevy 2500 HD, Firestone airbags, Air Lift wireless compressor, Curt gooseneck, 20K Reese Goosebox, TST-507, USMC combat vet & retired LEO. Robert, Anika, Breanna, Dylan & our Great Pyrenees Layla
432bartman is offline   Reply With Quote
Old 03-15-2023, 12:46 PM   #7
Joint Venture II
Montana Fan
Join Date: Mar 2022
Location: LYNDEN
Posts: 268
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.
2005 Keystone Montana 2955RL, MORryde Rubber Pin Box, Sailun 14PLY tires, TST 507 TPMS & Starlink RV.
1999 F350 SC LWB DRW 4WD V10 ZF6 4.30's, 90 gallon aux fuel tank. 6 years US Navy
Joint Venture II is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Powered by vBadvanced CMPS v3.2.3

This website is not affiliated with or endorsed by Montana RV, Keystone RV Company or any of its affiliates. This is an independent, unofficial site.

All times are GMT -6. The time now is 09:13 AM.

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2023, vBulletin Solutions, Inc.