Two Electrical Questions

[z28jimi]

On a 44 DB, which battery bank is the start bank for the genset? I think it's the port bank, but would like confirmation.

Second question: while running with the genset in operation, are the batteries being charged by the AC battery chargers (running off the genes) as well as the alternators, or is there an alternator cutout?

 

[JVM225]

1.Genny usually has its own battery and switch.
2. If you turn the AC converter on when running the genny it will charge the batteries. IfnI’m on the hook running the genny and have the AC converter on, I usually shut that breaker before I start the motors so as not to screw up the whole charging circuit.

 

[bajturner]

On my 44DB the generator starts from the port bank; here is no dedicated starting battery (a design I am not overly fond of). Here is the relevant section of the wiring diagram:

There is a dedicated energizing switch in the main electrical panel for the generator, but what it does is bring the port batteries on-line for the generator. I have added two more group 31s to the port bank (for a total of 4 on port, plus the two on starboard).

As for the charging, if you have the generator running and the converter/charger turned on while the main engines are on, both the alternators and the converter/charger will contribute to the charging. My understanding is there is no cut-out.

 

[z28jimi]

On my 44DB the generator starts from the port bank; here is no dedicated starting battery (a design I am not overly fond of). Here is the relevant section of the wiring diagram:

View attachment 59624

There is a dedicated energizing switch in the main electrical panel for the generator, but what it does is bring the port batteries on-line for the generator. I have added two more group 31s to the port bank (for a total of 4 on port, plus the two on starboard).

As for the charging, if you have the generator running and the converter/charger turned on while the main engines are on, both the alternators and the converter/charger will contribute to the charging. My understanding is there is no cut-out.

Thank you for the detailed response. That's the way I thought things were set up, but it's nice to get confirmation. Could you give me a little more info on where you located the additional batteries? I'm considering adding at least one, and a small charger, so that it can be dedicated to the genset, maybe with a paralleling switch of some sort on the off chance that battery goes kaput.

 

[bajturner]

Could you give me a little more info on where you located the additional batteries? I'm considering adding at least one, and a small charger, so that it can be dedicated to the genset, maybe with a paralleling switch of some sort on the off chance that battery goes kaput.

There was lots of room right beside the other port/starboard batteries. They all got rearranged but essentially there is one more next to the main DC connection box, and another at the back inboard side of the other battery. There is likely room for 1 or 2 more (thinking about it...and a new charger/converter!).

Before I changed all the batteries, I didn't realize the old ones were weak and ran the port bank down so low they couldn't start the generator. The solution I used was to start the starboard engine, use the emergency crossover to start the port engine, wait 5 minutes and then start the generator.

It would be a fairly big job to add a dedicated generator battery if you want to keep everything on-par with a factory install. Possible, but would require some thinking...

 

[bajturner]

Deleted my question here...realized it was actually an inadvertent attempted hi-jack (I thought I was on the 420/44DB thread when I posted it).

My apologies to the OP.

 

[z28jimi]

There was lots of room right beside the other port/starboard batteries. They all got rearranged but essentially there is one more next to the main DC connection box, and another at the back inboard side of the other battery. There is likely room for 1 or 2 more (thinking about it...and a new charger/converter!).

Before I changed all the batteries, I didn't realize the old ones were weak and ran the port bank down so low they couldn't start the generator. The solution I used was to start the starboard engine, use the emergency crossover to start the port engine, wait 5 minutes and then start the generator.

It would be a fairly big job to add a dedicated generator battery if you want to keep everything on-par with a factory install. Possible, but would require some thinking...

Thanks for the info. Gives me something to think about.