Killing batteries

[weewee]

I have a 2005 Yamaha 115 hp. It runs fine, but it is killing batteries..... They will take a charge at home, and the motor runs great if I put in a different battery but by the time I go anywhere the battery is dead again. I've been stuck on the water 2 times now. I replaced the battery the first time thinking that it was a 2 year old battery. Now it's happened again, with the new battery.

Anybody ever have this happen to them.

 

[reddogg]

Re: Killing batteries

Sounds like you've got a problem with your charging system, or rather your engine isn't charging your batt and is running off the batt itself killin it. If you have a multimeter, test batt voltage while engine is running and see if it's being charged or drained to verify.

Red

 

[weewee]

Re: Killing batteries

I know that it is draining the battery, what I would like to know is... where to look. It could be the several different things.... each one more exspensive than the last. So, if you have ideas, (other than the Generator) that would be great.

 

[99yam40]

Re: Killing batteries

I would be checking to see how the charging system was doing and if there was a short draining power

 

[weewee]

Re: Killing batteries

the only thing I've found so far is a blown fuse about 6 inches from the battery.... I have no Idea what it might go to. The boat is running now, but the volt meter is reading about 11 volts. Not sure where to go from here. Or is 11 volts going to be enough, I don't think I ever really noticed what it was at before.

 

[99yam40]

Re: Killing batteries

Take it to a shop as the charging system is not functioning as it should be around 13- 14 volts DC when the motor is running

 

[weewee]

Re: Killing batteries

OK, so.... I've figured out that it is my regulator, or generator. Short of just replaceing them to figure out which one it is..... Any ideas on how to test one or the other. All of the conections are water tight, and I can't get the Multimeter probes into anything. This is easy on a car or an inboard. Fixing this is a n brainer, but either is expensive, so I would like to up my odds of getting it right the first time.

 

[99yam40]

Re: Killing batteries

Your service manual should give you the points to test and the specs at different RPM.
A small stiff wire slid into the back side of the connector without damaging the insulation will usually do the trick, but a test harness comes in handy. I believe my C40 had a spec for unplugged and for plugged up

 

[weewee]

Re: Killing batteries

I spoke with a marine mechanic today, and the quick and dirty trick is to check your voltage with the motor running. If you get all the usual dips in volts that you should with no recovery and your tack work it's most likely the regulator. If you have the tach don't work it's probably the generator. Yes, this is for outboards only...... Thank you for all the words of wisdom.