2nd Gen Non-Engine/Transmission Changing group 27 batteries to 65’s or 31’s

[CCooper]

I am needing new batteries for my 2001. It came with group 27’s, is it worth the effort to modify the battery trays to accept a group 65 or 31 batteries? They seem to have a greater CCA and more reserve than 27’s. Are 31’s too tall to fit without hitting the hood with the stock battery trays? Thanks for any info and comments.



C Cooper

 

[Bob4x4]

I put 65's on my 94 no problem but I did fab up my own hold downs. The 31's are too long to fit in an un modified tray

 

[DMcLeod]

My 01 will be needing batteries one of these days also, and I've done a lot of reading on here about the 31's. A slight mod to the drivers side battery tray is required for the 31's - something like using a dremel to cut away a plastic gusset. A lot of folks run 31's and a few have said they required no mod to the trays at all. The vast majority however had to cut the tray a little. You will need to make or modify the hold down bracket/bolts for the 31. There are no clearance issues with the hood from what I've read.



I don't know much about the size 65.



In Optima brand, a couple of differences between the 31 and 27 follow:

D27F D31A&T

830cca 900cca

140 155 reserve capacity

53. 2 59. 8 weight



In a dual battery setup, are we really gaining a lot by going to the 31's over the 27's?

 

[hcole]

I just installed group 65 sears platinum in my truck. I had to insert a 3/4" piece of one by four 6" long in order to get the shorter in height 65's to clamp down with the stock brackets. Sears had them on sale in my area. They had (I think) app. 840 CCA. Just don't remember.

 

[PC12Driver]

I just installed group 65 sears platinum in my truck. I had to insert a 3/4" piece of one by four 6" long in order to get the shorter in height 65's to clamp down with the stock brackets. Sears had them on sale in my area. They had (I think) app. 840 CCA. Just don't remember.

I run those as well (930 CCA, btw) with a 3/4" spacer on the bottom. Don't forget to drill a hole to relocate the battery temp sensor (driver's side tray) to the top of the spacer. That'll keep the charging system volts correct and the battery happy.

 

[CCooper]

I decided to go with the best deal I could find locally. That was AutoZone Industrial group 31's. They are 950 CCA and a 195 reserve for $99. 99 each. I was going to try Walmart's but the best they had was 850 CCA, group 65's. I had to cut one side of the stock battery trays out to get them to fit but it was easy to do with a sawzall. This morning it was 2 below zero, cycled the heating grid just once and my Cummins came right to life. A huge improvement over the old Mopar 750 CCA I took out. Very glad I upgraded, well worth the effort.

C Cooper

 

[Joe Mc]

Back in early 05 I switched to the Walmart MAXX batteries. Went with whatever their book said would fit, they came with plastic spacers on the bottom to bump the height so the hold downs would work without mods. They've been going great 5+ years now.

Ah, I never did relocate the battery temp sensor, maybe it would be a good idea . . .

 

[The patriot]

I put 65's on my 94 no problem but I did fab up my own hold downs. The 31's are too long to fit in an un modified tray

The 31's fit in my 1998 tray.

It helps if it's warm out as it's a TIGHT fit.

Have to get longer bolts though.