Battery Group Size???

[Ted G]

As I am contemplating my battery box build in my trunk area, I obviously want to make sure I have enough room. What do most of you go with and what Cold Crank Amps would be ideal for a roadster? I was told at least 750 because of my engine size (351w stroked to 427), but wanted to reach out to the Forum Guru's. Anything else I should consider when buying a battery? I need a battery that is less than 7 1/4" tall. I also know a bunch will tell me to just get the Breeze Front Battery Box, but I have my reasons..... I think.

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I'm sure this topic has been approached before, but thanks in advance.

Ted G

[Jeff Kleiner]

Group 58. Plain old lead acid from Interstate or one of the big boxes like Autozone, etc. Don’t be drawn into the Optima trap ;) You don’t necessarily need 750 amps but with it mounted in the rear what you DO need are larger cables than the FFR supplied #4—step up to #2 on ALL of them.

Jeff

[rthomas98]

I ended up going with the Breeze battery box up front in the engine bay. That uses a group 51 battery.

[rich grsc]

What do you need a 750 CC amp battery for, you starting a 600 ci diesel? I have an Odyssey PC 680 battery, rated at 170 CC amp, it starts my high compression 331 every time without issues. Even after setting for 6 months, and never use a charger.

[Ted G]

Group 58. Plain old lead acid from Interstate or one of the big boxes like Autozone, etc. Don’t be drawn into the Optima trap ;) You don’t necessarily need 750 amps but with it mounted in the rear what you DO need are larger cables than the FFR supplied #4—step up to #2 on ALL of them.

Jeff

Thanks for the tips Jeff.... Duly noted and yes, my Optima in my Jeep failed way too early.

[Ted G]

What do you need a 750 CC amp battery for, you starting a 600 ci diesel? I have an Odyssey PC 680 battery, rated at 170 CC amp, it starts my high compression 331 every time without issues. Even after setting for 6 months, and never use a charger.

Thanks Rich, good info and I thought the guy at Autozone was a little crazy too.

[rich grsc]

Ted, you know I was just given you trouble right.:) But I have had great luck with the Odyssey battery, and will definitely buy the same when this one finally does need replacing.

[Ted G]

Ted, you know I was just given you trouble right.:) But I have had great luck with the Odyssey battery, and will definitely buy the same when this one finally does need replacing.

Rich, does your battery really only have 170 CCA? That seems really low. My biggest concern is getting my custom battery box to be able to receive several sizes... I just need a shorter battery.

[rich grsc]

It's a PC680, they say 170CCA on their site. I know I've never once had any trouble starting. I do have very short cables.
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[Hoooper]

Remember, CCA is a rating for amperage delivery when the battery is at 0 degrees F. You get cars with batteries with 750 CCA because they are sized for starting with the lights on in Minnesota in January when the temp is -40. When you are sizing one for a roadster that will rarely get started anywhere even just close to freezing the actual battery amp capacity is much higher than the CCA. You really shouldnt need any more than 250A to run the starter, and realistically closer to 200A, so the Odyssey which has an MCA of 280A (the rating at 32F) would be plenty of juice for the starting temps most on here will see.