12v or 24v Alternator For QSC 8.3L with a 24V starter bank

[Michael Cunningham]

New to forum. Hope this question falls within the bounds.

Have recently acquired a Nordic 44 with a 24v starter battery bank (two 12s in series) for a 600 HP, Cummins QSC 8.3L.  Recently, had an alternator failure while on a trip.  Replacement alternator (that a dockside mechanic put it in) was labelled 12V.  Was this an error?  Don’t I need a 24V alternator to charge my battery bank?  

 

Thanks,

 

Michae

Topic

[Gene Fuller]

The standard configuration for the Nordic Tug 44 has been 100% 24 volt since its inception about 10 years ago. (Update from the previous Nordic Tug 42).

Of course these are highly custom boats so anything is possible. However, it is very likely to be a completely 24 volt system, including all engine and battery related items as well as lighting, appliances, etc.

[Jason Leslie]

Just to clarify, you are sure you have two 12v batteries in series (+ of one battery connected to the negative of the other, then + of other battery to your load, and your negative of the other battery to your boat ground). This will in fact make the system a 24v system and must have a 24v alternator. My QSC 500 has two 12v batteries in parallel meaning both positives are connected to each other and both negatives are connected together causing double the amperage of the system but the system is still only a 12v system (but with twice the amperage). I’m only asking because you stated you recently acquired the vessel. Some people asume that two batteries means 24 volts. I’m hoping you mechanic is smart enough to figure that out and would have installed a 24v alternator if the system is wired as a 24v system. Any ways I wish you luck. It is easy to check by looking at your battery configuration or using a voltage tester. 

[donald roth]

You absolutely need a 24 volt alternator in a 24 volt system.                           Check the alternator output first to verify what it’s putting out vs what is stamped on the plate.

 

 

[Michael Cunningham]

Thanks, thought so (on both accounts), but new to tinkering.

[Clark Leighs]

My opinion.   If the original alternator was 24V then the replacement should be 24V.       I would question that mechanic, he should know better.

 

 

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