Battery charging setup

[Steve_in_lex]

Please bear with me on this - I'm a rookie on the battery charging process.

I just returned from chartering a boat in the Caribbean, and in the briefing I was told that there was a battery dedicated to starting the engine and another "domestic" battery for everything else.  Okay, got it.

But then they said that the domestic battery only charges up when the engine is in neutral, buy it does not charge when the engine is in forward.  That's different from what I believe is the setup in my C-34, where both batteries charge when the engine is running, whether in neutral or forward (depending on the 1/2/Both switch).

What kind of setup would charge when the engine's in neutral, but not in forward?

[KWKloeber]

What boat/what engine?

[LogoFreak]

That makes 0 sense. As far as I know charging isn't dependant on wether you're engine is in gear or not. Unless maybe the engine in that particular boat was very undersized and it couldn't perform double duty (charging and propulsion), but that would be the equivalent of saying you can't use the A/C while driving in your car, only when your parked with engine revved up...

More info needed for sure.

[Holger Dieske]

yes, they told you nonsense. The alternator charges if it is properly wired when the engine revs. Which gear does not matter, it is decided in the transmission.

Holger

[Jim Hardesty]

I was told that there was a battery dedicated to starting the engine and another "domestic" battery for everything else.  Okay, got it
But then they said that the domestic battery only charges up when the engine is in neutral, buy it does not charge when the engine is in forward.

It would be possible to design it to operate that way.  Don't know why it would be that way, can think of a few reasons not to.  Unless it had an auxiliary generator hooked up to run off the engine.   Better off not getting into it at the check-out, just do it their way and enjoy. 
Rest assured your Catalina wasn't designed that way.
Jim

[Steve_in_lex]

Thanks, all, for your comments.  It didn't make sense to me either so I'm glad I'm not crazy. 

FWIW, the boat was a Jeanneau 41 and the engine was a replacement that looked close to brand new.  The guy who did the briefing was very knowledgeable in every way except (seemingly) the engine.  I'll write the Sunsail/Moorings base in Tortola to comment on the recommendation to run the engine in neutral for 90 minutes, morning and evening, which is a buzz kill when at anchor in a beautiful setting.

[Ron Hill]

Steve : That only charging in neutral and not when the engine is in FWD or Reverse- does NOT compute!?!

My thought

[Admiral_Swellson]

The Mooring's guy undoubtedly knows what he's talking about for his own boats. This is probably a dual-alternator design with a huge second alternator to charge a lithium system, which you wouldn't want killing your horsepower when you need to steam, so it has a relay that only allows it to run in neutral. The biggest pet peave I had when chartering was the crappy house banks that couldn't keep the fridges running even 18 hours... A constant headache. 

[Noah]

Juno—Maybe? But the "need to run it 90 minutes TWICE DAILY"  sounds suspicious for a large alternator feeding a lithium bank.

[Admiral_Swellson]

Juno—Maybe? But the "need to run it 90 minutes TWICE DAILY"  sounds suspicious for a large alternator feeding a lithium bank.

Agreed, maybe large second alternator feeding crappy old batteries? 

[Steve_in_lex]

Robert/Juno, it sounds like you're onto something.  At any rate, it's only relevant for a future charter.   

In the course of researching this, I looked through the C34 comments and articles and am thiinking that I'll replace our boat's A/B switch with an automatic charging relay.  Several different people, all relatives, use our boat, and we've had people drain the batteries by leaving the switch on Both for a week at the mooring.  Not good for family relations.

Looks like ACR's are pretty idiot-proof.