Electrical issues

mwilson · Posted: Mon Jun 16, 2008 9:53 pm Post subject: Electrical issues

I have a 2000 22 with twin 40's, I have two batteries with a single perco on off switch that inputs the back up battery when turned to the on position.

The issue is after about 2 hours of trolling or so the main battery voltage plummets to 8 volts or so and of course things shut down. Sooo I just turn the switch and start things up again and after a few minutes I'm back up to 12 volts on the main so I switch back again. It runs fine again for a while.
I've had the battery checked its ok, cleaned the terminals and tightened the nuts down, but don't know where to start to try to figure this out any suggestions???

michael

Sneaks · Posted: Mon Jun 16, 2008 10:20 pm Post subject:

Please clear up a few nagging questions.

1) Are you trolling with a DC trolling motor?

2) Do you have only one battery installed?

3) If you have two batteries, how are they wired? House/engines? Trolling motor/engines?

4) If you're trolling on the main engines, what electronics etc. is the battery supplying power to?

Don

mwilson · Posted: Tue Jun 17, 2008 12:09 am Post subject: Electrical issues

I am trolling with one of the 40's. Two batteries one is the main the other is wired as a backup and for one of the 40's, I'm usually using a radio, gps, sonar and vhf radio. and electrical downriggers. Could trolling speed not be enough to keep full charge on the battery? The voltage drops off in one big jump not gradually. michael

Sneaks · Posted: Tue Jun 17, 2008 9:01 am Post subject:

Frankly, it doesn't sound that abnormal. It takes several hours to fully and properly charge a battery using those puny little outboard alternators and yes, battery voltage can drop very quickly if under load and undercharged.

On the other hand, how was your battery checked? Load check? Or just a voltage check? Some auto parts stores have the ability to load check a battery but in my opinion it's likely you're running with a partially charged battery and at trolling speeds it's not getting much (if any) help from the outboard's alternator.

Of course my opinion is worth precisely what you paid for it. Laughing

Don

lloyds · Posted: Tue Jun 17, 2008 11:03 am Post subject:

The accessories would keep a group 24 right on the edge if you used them full time while fishing. I would guess that at least one of those batteries has been run down too far, too many times, and isn't taking much of a charge so it does okay for awhile then just dies. Time to yank the batteries and do a load check. A more sophisticated battery management tool would prevent a lot of that in the future. I have never had the luxury of the fancy management switches but they will be the first thing added on the next boat.

mwilson · Posted: Tue Jun 17, 2008 9:13 pm Post subject: electrical issues

Thanks guys I'll get the batteries checked. michael