Two dead batteries

[Bozol]

I've got a 90hp Yamaha and its the only thing hooked up to the battery. I've had two deep cycle marine batteries go dead on me this summer. First time was in June. Boat started fine, went for a 45km cruise, stopped for a picnic and then it wouldn't start the boat for the return trip. Good thing had a spare battery.

Second time was this weekend. Saturday boat roared around a local lake, then camped for the night, the next afternoon engine nor trim would work. Luckily have a 15hp kicker that got us to the boat launch. Changed out the battery and it worked fine. I left the throttle in forward gear overnight. I usually leave the key in when the boat isn't on the trailer.

Any thoughts?

Bozol

 

[wire2]

Re: Two dead batteries

You may have a partial short in the motor. With motor off, key off, pull 1 cable off the battery, wire a small 12v lamp between the cable and the post. If the lamp glows even dimly, current is being drawn. That will kill the battery in time.

 

[Silvertip]

Re: Two dead batteries

bad diode in the charging system will suck it dry. Is the charging system working. (As in -- if your boat has a voltmeter, what does it tell you???)

 

[Bozol]

Re: Two dead batteries

No volt meter. The engine is 2 years old.

I'll try the lamp idea and see what happens. I'll report back when I've learned more.

Thanks for the advice.

 

[bruceb58]

Re: Two dead batteries

The lamp idea is pretty worthless. Buy a meter and put it between the battery lead and the battery instead in current measuring mode.

 

[Bozol]

Re: Two dead batteries

You mean keep one lead connected to the battery, undo the other and place the meter touching the battery terminal (that has no lead on it) and the loose lead?

 

[bruceb58]

Re: Two dead batteries

You mean keep one lead connected to the battery, undo the other and place the meter touching the battery terminal (that has no lead on it) and the loose lead?

yes