ksanders
Moderator Emeritus
I'm the outlier here. My 8 Ds work quite fine and provide good ballast. This is a trawler forum where ballast is not a bad word.
I use three 8Ds, 2 for engine starts and 1 for genset. and am quite happy with them. There is an already setup space for each and every five years the local yard spends about an hour lifting the main engine starts in and out. The first genset went 8 years with no problem.
Get some prices, question the crowd advice and make your own decision. 8Ds can be very cheap. Sticking with what works has no downside unless you insist on being the strong back rather than using a young buck.
Thanks for saying what I was thinking!
Not a darn thing wrong with using 8d's as starting batteries.
Both of my diesel pickups, and my Excursion (one Cummins, two Navistar) came factory stock with 2 group 31's as start batteries I believe. My boat came factory stock with one 8D for each engine, and a Group 31 for the generator.
Of course you can get by with a smaller battery much of the time. But if the day comes when you are out on the water and really need that 8D's cranking power, you'll be glad you have it.
For a house bank, it's a different story. We use L16's because we have the height to handle them. For smaller installations GC or T105's work great.
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