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MAN V12-1550 cranking amps

Discussion in 'Engines' started by xF_PP, Mar 27, 2016.

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  1. xF_PP, Mar 27, 2016
    #1
    xF_PP

    xF_PP New Member

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    Non of my manuals recommend the 24V Amps needed for cold cranking my twin V12-1550's.
    What is the max 5sec discharge current or MCA I have to plan for?

    The starters do have a 6.5kW rating.
    Last edited: Mar 27, 2016
  2. Capt Ralph, Mar 27, 2016
    #2
    Capt Ralph

    Capt Ralph Senior Member

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    My short library does not give a battery Amp spec either.
    The math proves 271 amps (w/v=a).

    Are you battery shopping or chasing down a problem?

    After the parasitic drops and losses thru the systems, a pair of 4Ds should do it, maybe a pair of good 31s @ 650CCAs. Just for starting with no problems.

    Usually the starting batteries are tied to the house or electronics that would require a bit more reserve.

    My observed history on the V-10s show in line 8Ds @ 1100CCA each.
    One customer had a pair of those square Odyssey batteries (1250CCA) turning the MANs over with no problems and the electronics usually stayed up.

    Good 4/0 cables make a difference also.
  3. BoulderGT3, Apr 3, 2016
    #3
    BoulderGT3

    BoulderGT3 Senior Member

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    FWIW, my 1550's have 3 dedicated group 31's for each motor.
  4. K1W1, Apr 4, 2016
    #4
    K1W1

    K1W1 Senior Member

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    How are the 3 per engine connected?
  5. BoulderGT3, Apr 4, 2016
    #5
    BoulderGT3

    BoulderGT3 Senior Member

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    K1W1- Apologies for the typo on my end, typing on a small screen.... 4 batteries on each side paired up to get 24v. I just replaced them a month ago. It came from the viking factory with this configuration instead of 8d's. I've not computed CCA comparisons as it's always worked well and they are easier to handle. I've never had to go to dual even when the other batteries were end of life. IMG_0215.JPG
  6. Capt J, Apr 5, 2016
    #6
    Capt J

    Capt J Senior Member

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    4 Group 31's should have plenty of CCA's to roll them over. Call a MAN dealer, but I run a boat with 1100 common rails and 2 group 31's fire it off and was how it was set up from the factory.