Battery Fitment vs Group Size Availability

[kishy]

Hiya

"Early boxes" (at least through 85, probably through 87) use a group 64 battery, which I would describe as tall, long, and kinda skinny. The cars which use this battery have a molded-in battery tray that is too narrow to fit a battery that is not "kinda skinny".

"Later boxes" (90-91 known for sure, probably 88-91) can take a group 65 battery, which is a pretty chubby guy and not at all convenient to carry around.

65 is a group size that is still used in modern vehicles, per my understanding. This seems to be why availability is pretty good on a group 65. If you look at AutoZone, for example, you can get a 65 in all of the brands/lines they carry.

Not so for 64, which seems to be more or less obsolete. Interstate and NAPA sell group 64 batteries, but other vendors do not, and either substitute a 56 in place of the 64 (56 is a physically and electrically smaller battery but I'm not entirely sure of all details) or they do not carry a battery for the car (for example, Canadian Tire - you cannot buy a battery for an 84 Town Car there, they say they don't carry one at all).

Furthermore, the places where you can get a 64 or a 56, the only available battery appears to be the most basic tier available - example, AutoZone does not sell a 64, and the 56 is only available in the basic Duralast branding, with no AGM options.

What's the best route to take, then, when trying to replace a battery in an older box?

I'm inclined to think maybe swap out all that is necessary to make it fit a 65...which I'm thinking involves replacement of the inner fender and some supporting bracketry as well. In my case specifically, I have a fairly new 65 sitting unused in my 91 because I can't move it to any of my other vehicles, which is annoying in itself.

From playing with part store sites it looks like the year to introduce the wider battery tray was 1988.

[87gtVIC]

I think I just cut the plastic ridge down and placed the larger battery in on my car. Of course the terminals were reversed so I had to take care of that with new power and ground cables.

[kishy]

Raining right now or I'd go mess around with it, but I could have sworn there was also the threaded end of a bolt sticking up beside the ridge so the battery would still sit lopsided on top of it.

The reversed terminals, that was the other thing. Kept trying to remember all that went wrong when I tried to pop the 65 into the Townie previously. That was definitely one of them. When I replaced my battery cables I believe there was enough slack on them to accommodate that.

[Kodachrome Wolf]

O’Reilly carries a Group 64 on their Premium line, so that falls in their middle tier stuff. That’s what I’ve got in the wagon, but IIRC the owner’s manual quick ID card said it took a BX-62. A group 62 is similar to the group 64, just not as long, but height and width they’re the same. I will say, good luck finding a group 62.

The ‘87 and earlier cars have a little nub towards the header panel to help keep the battery in place. If you set a group 65 in there, it’ll sit on top of it and could puncture the case, ask me how I know. If you grind out that nub, a group 65 would fit just fine.

If you don’t want to do that, a group 24 or 27 should fit reasonably well in the space assuming you don’t want to go with the group 64.

[sly]

I used a weird one in the Mad Marquis. I think it was a 24R (reversed terminals) because I had to put in an aftermarket universal battery tray and it's almost the same size as a 65 but short enough to fit even with that universal business.

[Tiggie]

I ran a 27F in my 82. I do not recall there being any problems. The hold down bracket fit but that doesn’t mean that someone didn’t get in there before me and mod it nicely. The 88 takes the Group 65 as expected.

[gadget73]

There is a bolt sticking up in there but you can remove it. I've been dealing with the same thing for years on mine, never really fixed it properly but I cut or removed the bolt and just stuck the 65 in there. No hold-downs or anything, its just perched there with hope and good will. Maybe there is a bungee, I don't remember. I know I had to stick one in there for tech inspection at the track once. The battery has been in there 4+ years at this point and I've been operating on the "ignorance is bliss" method for a while now.

[sxcpotatoes]

I cut down a yellow plastic/fiberglass waffle tray (I think it was something my brother had in his basement under a washer or dryer) and sat it down in the battery tray on the '82 to run a Group 65. The cables on it stretch juussst far enough to swap them to the proper terminals and it bolts in fine IIRC (but I don't know if the tie down is a universal or the factory one). I can measure that plastic tray for depth if anyone's interested. The termials are clear of the hood on the '82 with it closed, but I don't know how much, and I don't know if there's any extra depth in the TC/MVI vs the CV/GM.

[packman]

I replaced my battery tray with a JEGS universal tray. There was no metal left for the J-bolts on my original tray to latch on to. I tried a ratchet strap, but the battery still managed to move around. The JEGS tray seems to be firmly mounted. It fits (according to JEGS) groups 4, 29, 31, 53, 60 & 77 batteries. I was gonna cross that bridge when I got there as I am assembling battery cables; old ones were fairly chewed up.