Voltmeter bouncing, electronics "resetting"

[kknudson]

I have a new problem with my electrical system that I could use a little advice troubleshooting. This is my 2nd season with the boat and have not had this problem before.

My charging system says that the batteries are in trickle mode and they seem to both hold a charge. However, I need to use my emergency start to get the starboard engine to turn over and start.

When I am underway, my PORT engine voltmeter bounces from 12 to 16. Occaisionally, all of my electronics "reboot" (my radio, chartplotter, GPS, etc).

I usually run with the generator and charger on. I tried turning both off, but the meter keeps bouncing. I now assume that it's a alternator issue as there is no seperate regulator. Before I ripout and change my alternators, could this just be trashed batteries? Any other suggestions?

 

[Redhook98]

Bad battery cable most likely. Check all connections and clean them. Double check all of your grounds as well.

 

[OldSkool]

I agree with redhook98. Most likely harness/wiring issue.

 

[Aerobaticflyer]

I had the "bouncing voltmeter" like you but no other symptoms. Turned out to be poor connection from damaged wire on the alternator sensor. Since you are having related accessories affected not likely the same issue but easy to verify.

You say you run with the generator on and the charger on? If you are charging the batteries off the alternators should you have your on board charger on also? I know there is protective circuitry to prevent overcharging but perhaps it's not working? I always turn off my charger anytime my engines (alternators) are operating....just in case. Good luck with your issue.

 

[tobnpr]

Check the cable at the stbd engine battery as suggested- if it's tight and clean, gotta be the battery.
The fact that the engine will start off the port batt means all the "engine" side connections (starter, etc) are good...

 

[Voldad]

If the battery connection is good - check the battery switch.

 

[kknudson]

Fixed!

It was the alternator. The regulator is part of the alternator. I took it off, had it rebuilt at an auto alternator rebuild shop, then put it back on. No more bouncing.

Thanks for all the help.