Cranking Battery Issues

[omega]

I went out to the lake last weekend after fully charging my batteries. When I get to the lake and fire it up, I noticed that the voltage went down to 11.5V on the cranking battery. Well, I didn't think nothing of it until after fishing for a while (~2 hours), the battery went back up to about ~12.1V with the big motor off. Well, I thought I'd try to crank the big motor up again just to see if there was any difference. Just like I thought, the voltage went down to 11.4V. I monitored it all day (had jumper cables just in case ), and while running down the lake at WOT, the voltage was actually going down (lowest I saw was 11.1V). Shut the motor off again, and goes back up to 12.1V.

Question: Do you think I have a bad rectifier or a short somewhere dragging my battery down? I checked the batteries and they're all good. put fresh water in them just in case. I've had the boat for 2 years and never had any problems with it until now. I've been racking my brain trying to figure this out, and I have a tournament this weekend. Any help would be appreciated. Thanks

 

[flip1up]

I guess you dont have time to mess with it much with your T this weekend, I would trade the battery out with another and see if the guage show the same on the water. If it doesnt, then its the battery. If it does...... good luck.

 

[omega]

Forgot to mention my specs.
1995 Bullet 20XD
1997 Mercury 200 Pro Max
The cranking battery is a Trojan deep cycle
onboard charger is a Guest 2623 3 bank

I don't claim to be an expert by any means. I've only own a boat for 2 years, but I'm learning

 

[omega]

flip1up - 3/29/2007 5:05 PM

I guess you dont have time to mess with it much with your T this weekend, I would trade the battery out with another and see if the guage show the same on the water. If it doesnt, then its the battery. If it does...... good luck.

Yeah, I tried that thinking it was the battery. Swapped batteries, still the same thing. This is the only time I've noticed this. I;m clueless. Anything else I could check? Thanks for your quick reply!

 

[Liveliner]

Check to make sure your terminals are clean and tight. While the battery sits it shows what it should however when the enging is attempting to send current through it there may bu corosian or a loose groung causing it to arc power and actually discharge.

 

[2jigs]

Omega did you ever get your cranking battery situation strait? If so what was it?

 

[Guest]

sounds like you have charging system problems bad rectifier or stator

 

[omega]

Another thing I noticed was that my breakers tripped this weekend on my bilge and nav. lights. Sounds like who ever did the wiring job on this boat was a shade tree machanic. I'm going to open her up this weekend and try to see if I can troubleshoot the problem. Water pump also went out on me last weekend, but that's another story. I'll post an update and let you know what the problem was if I find it. Thanks for the replys!

 

[omega]

spam2381 - 4/3/2007 2:29 PM

sounds like you have charging system problems bad rectifier or stator

You might be right about the charging system, because I noticed huge voltage differences while charging my batteries (14.7V vs. 12.5V on the trolling batteries). Does that sound right?

 

[omega]

btw, I won my tournament last weekend. My water pump went out, but that didn't stop us from fishing. lol