battery

[wil141]

last two times i took the boat out got to the fishing hole when started to leave battery wouldn't start had to use me small battery jumper to start it the onle thing that was on was the fishfinder 898 humminbird.i charged it up when i got home oh the battery is only 2 month old.next morning i started it up and with moter running i checked the volts at idol it 12.35v if i increase the rpm's to 3000 after 5 minutes it will finally charge at 13.00v i checked the rectifier and it showes to be good i guess my question is shouldn't the votes be the same at idol as it woulb be at 3000rpm can someone explain this works thanks

 

[F_R]

Your rectifier is working (at least it is charging the battery). What we don't know is what motor you have (regulated or non-regulated charging system). Yours is working normally for a non-regulated system.

Something else in your boat could be drawing the battery down. Like a short circuit.

Alternator output at idle is less than at increased RPM.

 

[wil141]

thanks for your response f_r my motor is a 1994 johnson 48hp modelj48eslerd

 

[F_R]

That has a simple unregulated alternator. It puts out somewhere in the range of 5 AMPS. Not a lot, but some people complain of overcharging anyway because it is unregulated. Since the voltage increases when running, it is working. Next step is hunt down whatever is draining the battery.

 

[oldboat1]

Might be a starter issue. May want to take it off and have it tested. Or it may just need a cleaning or brushes replaced, which you could do yourself. First step is always to shine up the wire ends -- start with the main battery cables (shine them up with a piece of sandpaper).

 

[wil141]

thanks to both of you for the help i'll let you know what i find

 

[flyingscott]

What kind of battery are you using. The unregulated system shouldnt use a maintenance free battery. That is because it uses the battery as the regulator and they tend to boil out the acid. So a battery that you can check the levels on is a must.

 

[wil141]

thanks for the info flyingscott,the battery is 2mo old bought from academy 1000 cca group 24 you can check fluid levels in it i think i might have it tracked down to the stereo pulling the batt down while it sets between trips i think i'll invest in a perko switch after doing a couple more checks thanks for the help you guys