Does my ONAN need a new 12V charger?


Alex Ramseyer <alexramseyer@...>
 

When the generator runs, I see 13,6V on the starter battery. When I turn the ignition key of the engine in the cockpit the current goes down to 13,2V (maybe because of the ventilator in engine room / generator is still running). When I start the main engine the current goes to 14,4V.

After servicing the ONAN and replacing the starter battery a short while ago, everything worked find for a while, but this morning the ONAN only started AFTER I started the main engine. The starter battery showed 12, 4 V initially. It showed 13,2 after I run the genset for 2h and then 12,8 anoher 2h later. All observations come from the little display in the cockpit.

So what is the conclusion of you fellow Amelians from this observations?

Thanks, Alex
SY NO STRESS in Grenada
AMEL54 #15



greatketch@...
 

It certainly looks like the alternator on the Onan is not charging the battery.

Lots of possible reasons... 

As with anything electrical, start with ALL the connections.  They are not always the most likely cause, but they are cheap and easy to fix, so it makes sense to test them first.  Since the problem started after a service on the generator, it is quite possible you bumped a wire and broke a connection somewhere.  Many times I have been working in the engine room and managed to bump the main power switch on the genset...  "Why won't this darn things start???"

Be sure to NEVER disconnect the alternator from the battery when it is running.  That will kill the diodes in very short order.

If it turns out the alternator is the source of the problem, it is almost certainly able to be rebuilt at a fraction of the cost of a new one.  That service is available all over.

Bill Kinney
sm160, Harmonie
Fort Lauderdale, FL


---In amelyachtowners@..., <alexramseyer@...> wrote :

When the generator runs, I see 13,6V on the starter battery. When I turn the ignition key of the engine in the cockpit the current goes down to 13,2V (maybe because of the ventilator in engine room / generator is still running). When I start the main engine the current goes to 14,4V.

After servicing the ONAN and replacing the starter battery a short while ago, everything worked find for a while, but this morning the ONAN only started AFTER I started the main engine. The starter battery showed 12, 4 V initially. It showed 13,2 after I run the genset for 2h and then 12,8 anoher 2h later. All observations come from the little display in the cockpit.

So what is the conclusion of you fellow Amelians from this observations?

Thanks, Alex
SY NO STRESS in Grenada
AMEL54 #15