Back up battery CCA required - Diesel Forum

klahanie · 10-25-2009, 04:59 PM

I looking for additional batteries for camper "house" duties that can also be used for emergency engine starting if the truck batteries are dead. The OEM starting batteries are 2x750 CCA. Would lower rated camper batteries still be useful for starting or should they meet the rating?

Stymie · 10-25-2009, 06:24 PM

it depends on the weather. the diesel's batteries have that much CCA due to the amount of juice the glow plugs require(1100+ amps). so, in the summer time when the gp's ever even cycle, i'd say you could get by with less. but what are you doing that would kill a diesels batteries? i've sat in my truck for a full 2.5 hour stretch watching dvd's on my in dash and it didnt even flinch

klahanie · 10-25-2009, 06:54 PM

Quote:

Originally Posted by Stymie

it depends on the weather. the diesel's batteries have that much CCA due to the amount of juice the glow plugs require(1100+ amps).

Thanks Stymie, that makes a lot of sense. I wondered why it was spec'd so high.

Quote:

... but what are you doing that would kill a diesels batteries?

Probably something stupid...I haven't thought of it yet. But it might involve a winch.

**SmokeyWren** · 10-25-2009, 07:16 PM

Optima makes exactly what you're looking for. Optima Yellow-Top is a "tweener" battery, between a heavy duty starter battery and a deep-cycle RV or marine battery. It will work for both. Motorboats use it for cranking the engine as well as running the trolling motor all day.

Optima Part Number: D34/78 (8014-045)
YellowTop®; Deep Cycle Battery; UNBOXED; Group D34/78; Cold Crank Amps 750; Crank Amps 870; Res. Capacity 120; Ampere Hour 55; Top Terminal; L-10 in.; W-6 7/8 in.; H-7 13/16 in.;

That blurb doesn't mention it, but the size 34/78 has both top and side terminals. They also have a size 34 with top terminals only for a few bucks less.

Optima Battery Selector - Car Battery Selector by Optima

Not cheap, but it will do the job for you. I get mine at Sam's club.

As a pure RV battery, I prefer the even more expensive Optima Blue Top Marine deep-cycle battery. But they don't make it in size 34 with CCA of 750 or more.