Bad battery or wiring?

[john90290]

Attempting to bird dog this electrical issue. 1996 Overnighter with 2003 Yamaha 225, dual battery set up. I can start on battery one but the battery dies shortly after? thought I must have had some sort of slow drain so charged it overnight and then tried it again the next day. It ran for a few minutes I docked to get fuel, tried to restart and nothing, no gauges or anything on #1. I have to then go to #2 and start and it runs great, all day long, no issues, but switch to #1 and the engine dies in 20 seconds.

-Bad Battery? Maybe but they are new interstate group 24's
-Loose Wiring? Maybe, but what loose wire would let the engine run and start on #1 then deplete it? Seems it's not getting the charge from the alternator.
-Bad alternator? Maybe, but #2 battery runs all day long?

 

[onoahimahi]

My guess would be battery cable or battery switch. My understanding is that some motors will run with an open-circuited battery and some won't. I would try posted on Hull Truth...

-Scott

 

[freddy063]

check all your grounds. Most of the time I have battery troubles it ends up being a ground.

 

[seasick]

Attempting to bird dog this electrical issue. 1996 Overnighter with 2003 Yamaha 225, dual battery set up. I can start on battery one but the battery dies shortly after? thought I must have had some sort of slow drain so charged it overnight and then tried it again the next day. It ran for a few minutes I docked to get fuel, tried to restart and nothing, no gauges or anything on #1. I have to then go to #2 and start and it runs great, all day long, no issues, but switch to #1 and the engine dies in 20 seconds.

-Bad Battery? Maybe but they are new interstate group 24's
-Loose Wiring? Maybe, but what loose wire would let the engine run and start on #1 then deplete it? Seems it's not getting the charge from the alternator.
-Bad alternator? Maybe, but #2 battery runs all day long?

Swapping batteries will tell you if it is a battery or something else. I suspect a loose or corroded connector. Since one battery works, the problem if wiring would have to be somewhere between the problem battery and the battery switch. Check the ground cable between the batteries also.
If you have a voltmeter on the helm, note what you initial, idling and running voltages are. That will tell you to a point the state of the alternator.

 

[john90290]

Thanks guys,

I will pull the switch to see if there is a loose connection of one of the cables and then look at all the grounds. If that fails to resolve the issue i'll swap the batteries.

I will post the results.

-John

 

[NOTHING ELSE MATTERS]

Sounds like a bad ground bridge cable, most likely bad or loose connector on the "bad" battery side.

 

[BobP]

Connect a hand held digital voltmeter so it stays connected on motor leads, can do it on motor under cowl, then read it when the motor doesn't crank while holding key, position it so it is visible from helm. Then do same at trouble battery terminals.

What's the two readings?