6 CTA 8.3 M3 start battery - Cummins Marine Forum

This topic has 3 replies, 3 voices, and was last updated 1 year ago by Todd.

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November 3, 2022 at 11:52 am #138473

Todd
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I have a 1998 6 CTA 430HP with a recently rebuilt Bosch starter. It starts fine now. Boat has TWO AGM 8D start batteries, new, rated at 1450 cold cranking amps each. I am trying to find what the spec is and what the best practice is for start battery capacity. Elsewhere on this forum someone mentioned 1225 CCA was adequate, but I did not see any reference or documentation. I have never had an engine this large and never needed more than one start battery. I would like to move one of these start batteries to the house bank and install a battery bank switch so I can always use the house bank for starting if there is a problem. Thoughts?

Thank you

PS Enjoying my heavy duty Seaboard Marine T shirt from my last order….
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November 4, 2022 at 10:10 am #138502

Todd
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Great, thank you for the replies here.

November 4, 2022 at 9:04 am #138498

bluebyu
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Location: East Coast
Country: USA

With my 2 6CTA8.3 M3 engines I use a 4D for Port and 6 T105 (Interstate) Golf carts for starboard. (3 in parallel, 2 in series) From the book:

November 3, 2022 at 12:31 pm #138475

Jay Becker
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Vessel Name: Starlight
Engines: 6CTA 250 diamond
Location: Oxnard, CA
Country: USA

I remember the 1225 CCA was from one of Tony’s Cummins spec sheets here. I had the same setup on same engines but thought the two AGM 8Ds were overkill. When they were due for replacement I put in two AGM Group 31s. Engines start fine. Using the two Gp 31s allowed me to leave the existing cables in place. Only had to change the battery hold down gear.
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