Good point. But as others have pointed out a pair of group 31s will give you enough CCAs and be easier on the back than a single 8D.What about boating and anchoring in below freezing conditions? Wouldn't you want that extra bit of oomph, just in case?
Another way to think about it is any battery that will reliably fire up your diesel pick up on a freezing morning will spin your yacht's engine just as well. Your engine room won't get as cold overnight as your driveway.
What about boating and anchoring in below freezing conditions? Wouldn't you want that extra bit of oomph, just in case?
My Cummins 5.9-powered Dodge pickup sits outside all winter at 4400 feet elevation in Utah, often 10-15 degrees in the morning. A pair of g34 AGM's in parallel has never had any trouble starting it. A pair of g34 AGM's is the start bank for my Volvo KAD44P-powered 26-footer.That is an excellent point. Never thought about it that way. Handy for me as my engine is put in a lot of diesel pickups.
I just checked. My Cummins QSB 5.9 engine is used in a number of Dodge trucks as well as RVs etc... They are installed with two Group 34 batteries. Minimum CCA is 750 amps.
Iirc, CCA is the amount that the batteries will put out at zero degrees. In my boat, which is kept in the water year round, I never get close to zero degrees. It seems to me that if Dodge and Cummins think that a couple of group 34 batteries are adequate to start a diesel truck in the winter in the mid-west, then that is way overkill for my boat sitting in relatively warm water.
For the Nordic Tug's 5.9 Cummins, I replaced an old 4D with a pair of g31 AGM's. They spin it effortlessly.