alternator question

[buckeyeryan]

I have the 5.7L monsoon in my 2002 response. I was doing some troubleshooting yesterday evening to find out why my battery keeps dying so fast. I found that the output voltage on my alternator is only 12.2 volts compared to my truck having 15.3 volts. Granted the boat was at idle but shouldn't it be higher than 12.2? Any insight to the problem would help. Thanks

[electricjohn]

Never lower than 13.8 when engine is running. At 12.2 you were reading your dying batteries' voltage.

[Pistol Pete]

It seems that your alt. is not putting out any juice.

When you say "my battery keeps dying so fast" What do you mean? You're out on the water until the boat won't start anymore and you get towed in?

Then, when your boat is home, you charge up the batteries?

[REW]

Output on an altinator should be around 14 vdc range of 13.5 to 14.5 is acceptable. 12.2 is your battery voltage. if you need to see it running take a reading on the system under load the system should still hold 13.5 to 14.5 with all electronics on and charging the battery and running the boat.

REW

Belt?

[Ski 01]

Once on my 5.7L (01) I had a simlar problem. I found in the end all that was need was a Master reset (52). As soon as i did this the Alternator came a live and did what it is ment to do.

Its worth a try

[buckeyeryan]

Once on my 5.7L (01) I had a simlar problem. I found in the end all that was need was a Master reset (52). As soon as i did this the Alternator came a live and did what it is ment to do.

Its worth a try

How do you do a master reset??

[buckeyeryan]

Output on an altinator should be around 14 vdc range of 13.5 to 14.5 is acceptable. 12.2 is your battery voltage. if you need to see it running take a reading on the system under load the system should still hold 13.5 to 14.5 with all electronics on and charging the battery and running the boat.

REW

Belt?

I replaced the belt as it was a little loose and the alternator was at the end of the adjustment. No change on the output. The voltage I was reading was not the battery voltage because I measured with a multimeter before I started the boat and the reading was 0vdc. When I started the engine however, that's when I got the 12.2 volts. I think I just need to get it rebuilt or get a new one.

[REW]

I replaced the belt as it was a little loose and the alternator was at the end of the adjustment. No change on the output. The voltage I was reading was not the battery voltage because I measured with a multimeter before I started the boat and the reading was 0vdc. When I started the engine however, that's when I got the 12.2 volts. I think I just need to get it rebuilt or get a new one.

That still may be the battery voltage as it will be isolated with the switch off and connected with it running. Check the voltage at the batteries prior to connection and then after connection as well as after starting the engine. There should be an obvious increase in voltage with the altinator operating. Not saying the you don't need a rebuild but if the problem is a connection or something similar it could save you some money.

make sure you get a marine part as it will be sealed to prevent sparks in the motor box.

Good luck

REW

[Lance B. Johnson]

That still may be the battery voltage as it will be isolated with the switch off and connected with it running. Check the voltage at the batteries prior to connection and then after connection as well as after starting the engine. There should be an obvious increase in voltage with the altinator operating. Not saying the you don't need a rebuild but if the problem is a connection or something similar it could save you some money.

make sure you get a marine part as it will be sealed to prevent sparks in the motor box.

Good luck

REW

I agree with REW. It is likely your alternator but you have to be careful, there may be a bad connection. The best way to find these poor connections with with a voltage drop test using your multimeter. Google voltage drop, somewhere there should be a webpage that shows you how.