Alternator Output question
 

Yesterday my 2 Odyssey bateries were dead on the boat. I forgot to turn off battery switches and I think I left the stereo (or something) on. :chimp:
The port battery was about dead while the starbord battery was a little better off. Neither would start the motor, but stbd battery raised the engine hatch just fine. The port battery wouldn't even power the GPS up.

Anyway, once started and at cruising spped I noticed that the port motor alternator was only putting out 12.7 volts ( at speed) and the stbd was 13.5 volts. Later in the day, I switched the battery switch so port motor was charging the stbd battery and stb charging the port.

Later I switched batteries back to normal(port to port - stb to stb). The port motor alternator was then putting out 12.9 to 13.0 volts and stbd still 13.5 volts.

I checked the alternator connections. The port connection showed some corrosion. It was cleaned 100%. Stb connection - fine. Battery connections: tight and clean.

Question: is my port alternator in need of service or was the lower voltage on port side due to the port battery being more dead than the starbord?

I have never noticed any problem before the dead batteries. While cruising, the port battery would read 13.8 volts.


(Motors are 2002 - 575SCi's. 60 amp / 847 watt alternator)

Re: Alternator Output question
 

im assuming that you have mercs with mando altanators..they should be putting out about 13.8 volts take a dvm to the red or orange wire comming off the back and verifie the voltage... before doing so charge the batts at 2amps for about 5 hrs if voltage reading still belowe low re place

sorry abouth the spelling sun morning

Re: Alternator Output question
 

Already answered on the "Other" site. --- Jer

Re: Alternator Output question
 

The Mando alternator has an adjustable regulator. The adjustment is made with a potentiometer inside the removable regulator, the component attached to the back of the alternator that is shaped sort of like a bell. If you remove the regulator and make up some jumper wires you can adjust it with the engine running.

Put a new fresh fully charged battery ( should read about 12.6 24 hours after being charged) and run the engine at fast idle. Tweak the pot a little and you will see that you can vary the voltage. Hook a DVM to the battery and monitor the voltage while adjusting. I set mine to put out 14.2 at a high idle.

Re: Alternator Output question
 

bad dog thanks learn something new every day