Replacing "Cummins Batteries"

[kenyu73]

My 4600 has Cummins batteries for both the genset and motors/house.

Is there any reason why I'd need to stick with Cummins batteries?

I'd rather use dedicated standard (Interstate) starter batteries and reconfigure my 12v for dedicated 31 series AGMs.

Comments?

[SteveP]

I replaced the starting 8Ds with 2 Group 31s in parallel. More cranking amps and much easier to move in/out of the engine room. Plan to do the same with a few smaller deep cycle batteries when my 8D house battery needs replacing.

[PJHoffnet]

No, there is no reason you'd need to stick with Cummins batteries.

We currently have three Victron Super Cycle batteries (12V 230Ah each).

[kenyu73]

What MCA (marine cranking amps or nominal cranking amps) do we think is minimal for the 6CTA 8.3 motors?

I'm looking at some 31 AGMs and it has 1030 MCAs but I think the motor manual for the boat says something like 1150.

[shrew]

Originally Posted by kenyu73

What MCA (marine cranking amps or nominal cranking amps) do we think is minimal for the 6CTA 8.3 motors?

I'm looking at some 31 AGMs and it has 1030 MCAs but I think the motor manual for the boat says something like 1150.

1030 would be very high for a Group 31. The 1150 requirement is why it was suggested to consider 2 x Group 31 wired in Parallel. That should keep the bank at 12V while doubling the capacity. Even a Group 31 with 800 CCA, would be 1600 CCA when wired in parallel.