Dead Batteries

[cyclops222]

Corroded battery clamps . Not tightened enough ?

 

[Dubed]

I took the day off from work tomorrow to go through the whole system.
I'll check and clean all connections and grounds. The batteries were good, so I'll install them. Im also going to install a real marine battery charger. After all that is done, I'll take it out for the day (and bring a multimeter) and see if the problem continues. If the issue continues, I'll install the new starter.
Thats the plan

 

[cyclops222]

Well if the batteries tested GOOD. And the trouble disappeared AFTER you changed batteries ? I vote the battery cable clamps being loose, were the problem.

 

[Dubed]

Update;
Was on the water for 10 hours yesterday fishing. Shut off motor in between drifts all day, never had a problem starting back up.
I cleaned and all connections in the circuit, apparently it was a bad connection somewhere but I really didn't see one with issues. Guess I got it though.

 

[Lou C]

Wing nuts holding down battery terminals on the battery? If so replace with self locking nuts. I use marine grade battery clamps on mine. Easy to change when they get corroded. Also you can get green corrosion under the insulation that you might not see. I replaced all the cables in my boat when I installed the dual battery system 15 years ago but they may be ready for replacement again. Already replaced the common to starter solenoid cable due to a past leak from the drain on the old exhaust manifolds (right on the solenoid lol). The other thing I have found is this, on many boats with an alternator that uses voltage sensing should really be using direct battery voltage to determine charging rate. Often there are not set up this way and then due to resistance in the circuits the battery never gets fully charged. When I have the manifolds off next time I will have better access to the engine wiring harness & will re wire it the way it should be. Currently losing about .2 volt between the alternator and battery.

 

[Dubed]

Wing nuts holding down battery terminals on the battery? If so replace with self locking nuts. I use marine grade battery clamps on mine. Easy to change when they get corroded. Also you can get green corrosion under the insulation that you might not see. I replaced all the cables in my boat when I installed the dual battery system 15 years ago but they may be ready for replacement again. Already replaced the common to starter solenoid cable due to a past leak from the drain on the old exhaust manifolds (right on the solenoid lol). The other thing I have found is this, on many boats with an alternator that uses voltage sensing should really be using direct battery voltage to determine charging rate. Often there are not set up this way and then due to resistance in the circuits the battery never gets fully charged. When I have the manifolds off next time I will have better access to the engine wiring harness & will re wire it the way it should be. Currently losing about .2 volt between the alternator and battery.

No wing nuts, no corrosion. Part of my commission routine every year is to clean each and every connection with a brass wire wheel. This was only the 3rd time I used the boat this year, everything was still nice and shiny.
The one thing I found that may have been an issue was one terminal connection had a shrink tube that was a bit too far up on the ring. Maybe that prevented a good solid connection??? Who knows

 

[Lou C]

Could be; doesn’t take much!

 

[airshot]

No wing nuts, no corrosion. Part of my commission routine every year is to clean each and every connection with a brass wire wheel. This was only the 3rd time I used the boat this year, everything was still nice and shiny.
The one thing I found that may have been an issue was one terminal connection had a shrink tube that was a bit too far up on the ring. Maybe that prevented a good solid connection??? Who knows

Have had that issue in the past...darn hard to find/ figure out ! Doesn't take much to gave a poor connection. I carry a small brass brush in my tool kit to clean all connections when ever an have something apart.

 

[dingbat]

The one thing I found that may have been an issue was one terminal connection had a shrink tube that was a bit too far up on the ring. Maybe that prevented a good solid connection??? Who knows

Doubt it.....The higher the current the more potential involved. May have added some resistance (heat) but if the terminal connector fit on the post with the nut on top, you had plenty of contact area