batteries for 502's

[maagee79]

My friend has a 38ft Pacemaker with twin 502's the batteries in it are bad and need to be replaced. The previous owner had huge 1350 cranking amp tractor batteries in this boat. What do you think would be the best to replace in this boat. They will be used just for starting. It has a gen that has its own battery and a charger that is running when the gen is on.

 

[Don S]

Re: batteries for 502's

From the Mercruiser applications manual.

Cranking Battery Specifications
Carbed engines ---- Minimum ratings 375 cca / 475 mca / 90 Ah
MPI engines ------- Minimum ratings 750 cca / 950 mca / 180 Ah

 

[Bondo]

Re: batteries for 502's

Ayuh,.... Those are Minimums,....

With Batteries, More Power, is Always Better,...

 

[haulnazz15]

Re: batteries for 502's

I'd say anything with 750+CCAs is probably sufficient, but it never hurts to go bigger. No need to have fancy Optima batteries if you don't want to spend the money, the Wally World/Sears batteries work just as well in my experiences for starting purposes and respond much better to being discharged/recharged.