Charging Question

[jwr_20]

Hello everyone!

I have a question about my charging system. The motor I have uses an alternator. I noticed that my batteries are being drained, and not being charged back up again. I tested the battery with the engine off and the output is normal (12-12.5V), and it is roughly the same output when the engine is running at idle, and at 3000 rpm, that's on a freshly charged battery. My batteries are great, there's no question about that. I get readings of 120 VAC directly from the back of the alternator, and the leads run to what appears to be a rectifier mounted on the rear of the alternator, which runs to the battery. I am assuming the rectifier is the problem. Is there a way I can test it myself easily? The electrical system seems to be very simple, my outboard looked more hi-tech than this.

Thanks any help.

 

[Bondo]

Re: Charging Question

Without knowing What Motor your talking about,........Muchless Which Alt.....

This Question is Unanswerable.....................

 

[fendersfender]

Re: Charging Question

voltage at battery while engine is running should be higher, say 13-13.5 volts, than when not running.....i'm with bondo...more info please

 

[bjcsc]

Re: Charging Question

12.0V-12.5V is not normal, it's low. 12.4V=25% discharged. 12.7+V=100% charged. While running, as said, you should see mid-high 13's when measuring at the battery. The short answer to your question is buy a new alternator.

The box you are referring to is most likely a regulator. Your problem is most likely diode related. These alts are three phase and thus have three pairs of diodes. While they can be disassembled, diagnosed, and replaced, typically they fail late in an alternator's life and other components may not be far behind.

Toss it and get a new one.

 

[thrasher]

Re: Charging Question

I have to aree with bjcsc, even if you changed the regulator, the brushes will be worn and the bearings are probably tired. It is much easier and wiser to just replace the alternator.. We live in a throw away society....

Gary

 

[Coors]

Re: Charging Question

Or have it rebuilt, for about $125.