karateboi87

Oops... bought a group 75 thinking it would fit my 2004 C5... nope, need a group 86. The battery is actually the same size for the most part but the damn wires miss it by like half an inch. Hopefully advanced auto parts will let me take it back.

What's really weird is that the group 75 has the 115 RM that I want but their group 86 one (same, both gold) only has 95RM. Has anyone else noticed that? Same price too...

I found Autozone's gold duralast with same specs except it has 105 RM, guess I'll go pick that up tomorrow.

LoneStarFRC

Your '04 uses a top terminal battery right? Group 75s are side terminal, unless you actually have a 75/35 dual-terminal.

If you want more RC and CCAs, check either a 34/78 (if your cables reach) or better yet go to Sears and buy a Die-Hard Platinum P4, but again just make sure your cables reach OK. The 34/78 is also a dual-terminal battery and the Sears unit is an AGM type with 135 RC and 880 CCA.

karateboi87

That's what I'm saying.. my 04 takes a group 86... apparently from 97-00 it is group 75(side terminal), 01-03 is 34/78, and 04 is 85 (top terminal). I bought a 34/78 and it won't connect cuz it's like half an inch different.

LoneStarFRC

All C5s came with a side post battery except for the '04 model year which is top post. No C5 ever came from the factory with a dual-terminal battery. Some battery manufacturers and auto parts stores show a listing for a dual terminal battery in some cases because it will work fine, as long as the cables reach OK. After that, the only other thing to consider is CCA and RC ratings. Any C5 with a dual-terminal battery in it is because some owner has installed it.

The 34/78 is just the dual-terminal, heavy duty version of the 75/35, which is also a dual terminal.

If you want a heavier duty (more CCAs and higher RCs) top post only, check the fitment of a group 34 (not 34/78, just Group 34). It is a top terminal battery. Physically it will fit in the tray just fine, but of course the cables have to reach as well.

Are your cables coming in from "behind" the battery? IOW, are the posts on your old 86 battery closer to the back edge or the front edge? If they are closer to the back edge, in order for your cables to reach, you can also check a group 24F and simply turn the battery around so the cables are oriented pos/pos and neg/neg and will hook up correctly.

The reason I mention this is because most all Group 86 batteries are wimpy 90 or 95 RC with CCAs in the low to mid 500 range, and I would not use it if I could help it.

The Group 24 and 24F (the "F" has it terminals reversed for use on Fords mainly as their terminals are opposite to everyone else's) are a very common top post group size and have been around for many years. The physical size is similar to the 74s and 75s Pretty much all battery manufacturers make a Group 24 (and 24F) and you can then pick from a variety of CCAs and RCs as well, within that Group size. You can find 24s in the 700 - 800 CCA range and RCs up in the 100 - 115 range, depending on the manufacturer.

At the end of the day, as long as the terminal placement allows you to hook your cables up OK, and the physical size (aka "Group size") fits your tray OK allowing you to clamp it in position, and the RC/CCA numbers are good, that's all that really matters. The car does not "know" (nor "care" ) which battery is installed, and as long as it fufills those three criteria, it will perform just fine.

HTH

65GGvert

I'd think you should be asking Advance Auto (unless you actually have an advanced auto parts store where you live) if you can exchange the wrong battery for the correct battery. I find that they usually try to make the customer happy as long as you didn't do anything to damage the battery.

Vetteman Jack

Don't know why the store won't take the battery back and let you exchange it for one that fits, especially if it was just bought within the last day or two.

karateboi87

Yeah I did some research and found that the same battery for group 86 has a lower RC even though the cost is actually $10 higher. I saw Auto Zone with the same thing with higher RC but after I got the battery it shows a lower RC (website shows different RC). I ended up calling Johnson Controls and they said what the battery lists is correct.

Oh well, I just bought the advanced auto group 86 one

B747VET

FWIW...

Paul Koerner, World Class GM Technician, @ Carlisle Seminars on C5 Column Lock Issues, Electrical Issues and the Right Battery


AC Delco Professional 78-6YR 700 CCA 120 RC (Part Number 19001632)
Note: 2004 C5 needs 86-6YR 700 CCA 120 RC

AntonioZ06

Just about every auto parts store will tell you the wrong battery class and insist they're correct because their records weren't updated each time the C5 changed battery classes.

rdwiv

Make sure you get 120 RC.....

russarm1

I just looked at my 04 and it has a CCA590 RC 110 86-7yr battery in it. It's probably on its last go around for this winter.

Jistari

These two points (above) will be helpful if you decide to go with the Die Hard Platinum, resurected a post showing why at Sears anyway

Quote:

For those thinking of going with a Die Hard Platinum, be advised that if you walk into Sears and tell them you have a 97-04 Corvette their computer may say that you need a

P3 75/86DT CCA 710 RC 90

The correct Die Hard Platinum battery for the C5 is a

P4 34/78DT CCA 880 RC 135

Regarding the P3
This battery is smaller than your tray, and when they first gave me this one I installed it, tourqued the terminals and cranked the hold down bracket as tight as it would go. Ive been using a Ctek Battery charger for some time now so the lower RC did not effect me at first. What did affect me was in testing the car after doing C6Z51 sways, shocks and endlinks I kept getting a "thunk" on hard cornering. We went over and over the suspension work looking for the cause of that thunk.
As a last resort I grabbed the battery and pushed on it.......yup.....thunk OMG, it was sliding back and forth in the tray, how embarrasing
At any rate, this battery is small for the tray and IMO has too low an RC for a C5.

Regarding the P4
Fits the tray, and has more CCA and the better RC.

Yup, they are heavy but they wont leak and I no longer have to worry about it not starting if Im away on vacation.

Works for me

End Quote