2004 3600 Sovran weak starboard starting

[Tantram]

Greetings,

My starboard engine is having a tough time starting, and I think it's likely a bad battery since it turns over just fine if I enable the crossover.

I dropped my head down below to check out the batteries and was a little overwhelmed, not knowing which battery goes to what or even how to get them out of the tight space and replaced.

Is there an idiot's guide to the battery layout or some tips and tricks that may point me in the correct direction?

Thanks for listening to an idiot

[Sans Peur]

First thing to check is the terminal connections. Make sure they are clean and tight. If all is well there you may have a bad battery (or two) on the starboard bank of batteries. Turn off rhe battery charger, disconnect the negative cable and load test each one individually. That will tell you which one's are going bad.

[neto]

How many battery banks do you have? If only two (Engine bank and House bank), try tracing the starter wire and verify its connected to the same place your other engine's starter is taking the juice... It could be that that specific starter is connected to the house battery bank and those deep cycle batteries have much less cranking amps to start an engine, much less a 450C. If they are indeed connected to the same bank, then my next move would be to clean terminals and try again. What starter do you have? 38mt or 42mt?