sprink58

Here's a hypothetical question: you have a twin engine set up with twin batteries and a battery switch. The engine that runs the power steering pump has 2: belts...1: for the PS pump & 1: for the alternator.Both belts run the circulating water pump on the PS Engine.

One day your out and you loose the belt for the alternator on the PS engine. You still have water circulation and PS on that engine but no alternator. Everything seems to be normal.

Is there any real issue in running the one engine with no alternator as long as the other engine is charging the batteries?

befu

iTrader: (2)

My first reaction says no, the electrical system is all tied together. One alternator should put out plenty of amperage to run both motors ignition. Of course there really isn't a good option on long idles on just one motor though. But then, if you have two good batteries, they would run engine for a long time and still have juice to crank other motor over.

Goes against your redundant reliability setup though. But as you mentioned, dual batteries already. could probably boat half a day without any alternator. Had the alt belt break on a 1984 car once driving ome from college, drove almost three hours before ignition died, and it wasn't a great battery!

Thinking of running just one alt for some reason?

Brian

sprink58

Thinking of running just one alt for some reason?


No...just wondering...if that one did go bad...or you lost a belt, you could still run well on one. In another look at the situation...it really wouldn't be worth the trouble to change the belt at sea, or be freaked out by having an alternator go bad as long as you could maintain full function long enough to get where your going in order to make repairs.

I had an alternator go out on my 40EC Sea Ray once and I could not run that engine with out drawing it's battery down. I can't remember exactly why but seems like those two engines electrical systems didn't interconnect but both batteries were in the starting circuit for both...but not in the charging circuit. I had to run the generator full time to keep the battery charger charging both batteries.

I really do hate working in the bilge of a boat offshore (can you say SEASICK!!) so if I didn't have to I wouldn't. Makes a good argument for double pulley, double belt alternators.

macjazzy

Was on a friends 2004 38' Fountain Lightning we had trailered down to Ft. Lauderdale. We had a week long trip planned, boating in Miami for a few days, then to Islamorada, then on to Key West for the races, First night out in Florida, alarm goes off for one engine. We diagnosed one alternator not charging. Switched batt switch to both and boated the rest of the week, no issues at all. Twin 525's