Engine Starting Issue

Discussion in 'Marine Electrical / Electronics' started by nickr917, Jun 8, 2018.

  1. nickr917

    nickr917 Member

    Aug 26, 2014
    Likes Received:
    When I bought my boat I learned that the installed automatic charging relay was broken so both battery banks were always combined. The banks are a house battery bank (4 Interstate Deep Cycle Extreme GC2-XHD-UTL golf cart batteries for a total of 464 Ah across all batteries) and an engine starting / bowthruster battery (Interstate Deep Cycle SRM-29 with 675 CCA/845CA). With both banks combined by default, the engine always started instantly.

    After disconnecting the ACR, the engine starting battery would no longer start the engine. The engine would crank slowly but would not start. The engine is a Perkins Sable M300Ti. I assumed the battery must have been worn out so I bought a generic Autozone marine deep cycle battery with 675 CCA/840CA to test that idea out. I charged the new battery before installing but still only got the engine to crank slowly.

    Since the engine starts easily when both battery banks are combined, it seems the straightforward solution would be to get a more powerful starting battery. However, based on the guidelines in the table below, I think this battery should be able to start the engine. Am I correct about that? If so, what other issues might I be having?

  2. Diesel Jerry

    Diesel Jerry Captain

    Oct 25, 2015
    Likes Received:
    Marine Diesel Mechanic and Systems Technician
    South Freeport, ME
    Check all grounds, and connections. What does the wire look like and is it the appropriate size for the job.
  3. Genius

    Genius Captain

    Feb 11, 2016
    Likes Received:
    Rhode Island
    Electrical troubleshooting really is an art. Draw out your electric system on a piece of paper so you can refer to it and it helps understanding it. Great suggestion from Jerry to start with. Some battery cables corrode from the inside and it's not apparent that they have been compromised. Using a multimeter you can check voltage drop with a friend. Black lead on one side of the cable and the red on the other, crank the engine. This will give you the voltage drop across that cable. If you have a bad one, it will be very apparent. You can do this with the whole line, or individual components. From the sheet you posted, It almost sounds like it wants two batteries in series. Cable length also plays an important factor.

    Edit: sorry, I meant "in parallel"
    Last edited: Jun 10, 2018
  4. steveinak

    steveinak Captain

    Sep 1, 2011
    Likes Received:
    Piker Central
    Boat Make:
    H&H / Pen Bay
    might it be a 24 volt starter/system ?
    Genius likes this.

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