Not charging battery

S

san dimas

Petty Officer 1st Class
Joined
Jan 20, 2012
Messages
369
Hello everyone.
My 1989 15 hp electric start Evinrude isn't charging the battery at any rpm. Checked rectifier and diodes have continuity both ways. Checked it again this morning when cooler and they have continuity only one way. I set the rectifier in the sun to warm up and now it shows continuity again both ways. Bad rectifier?
 
B

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: Not charging battery

As a guess, I would say yes. Heat always effects electrical parts.
 
B

bonzoscott

Senior Chief Petty Officer
Joined
Jul 26, 2008
Messages
745
Re: Not charging battery

They don't put out much voltage. My experience is "only enough to replace what was used to start". Are you running other accessories? Start the motor - pull the hot cable from the battery. Check the voltage from the loose hot cable to the battery ground. At idle - should show 2-3 volts. At 1/3 throttle it should bump up to 6-8 volts. Under full throttle (and don't try this on muffs) - should be 12-13 volts. If you get to the 6-8 volts at 1/3 throttle, you''re rectifier is probably okay. Rectifiers do get hot under load - just enough / too hot to touch very long.
 
C

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,025
Re: Not charging battery

if it is just a rectifier why not swap in a Radio Shack 50V 25 amp unit ($4) and test it out .
 
Last edited:
S

san dimas

Petty Officer 1st Class
Joined
Jan 20, 2012
Messages
369
Re: Not charging battery

Thanks bonzoscott. With the engine running at idle without the battery, I put a volt meter across the 2 leads and got 5 volts. when I charged the battery fully on the bench, and reinstalled the battery it showed 13 volts at idle and 13 volts at 2500 rpm. After I charged the battery on the bench, it showed 13 volts also. So there was no difference in battery voltage on the bench or in the boat. Would you think that may be normal when the battery is fully charged?
 
S

san dimas

Petty Officer 1st Class
Joined
Jan 20, 2012
Messages
369
Re: Not charging battery

I forgot to say, I'm not running any accessories.
 
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