Battery bank issue.

[Danos express]

2005 330 express
1.
Had a known good shore tie cord show a “reverse polarity” light in the panel. Unplugged before energizing and tested with VOM. L6-30 plug tested correctly. Plugged back in and had NO power … checked breaker under starboard quarter .. open and closed twice, no change. Stumped

2.
Starboard bank (house batts) are not charging under gen set, motors OR shore power (before above condition was found). Not related to motors charging circuit and I get active lights on the onboard charger. If I plug k. A stand alone charger, it will charge the back. Checked battery switches on port transom. Figured all charge / discharge needs to go through those switches. Am I missing something ?? Connection to batt posts are all tight. New batteries 2 months ago. Load tested once up to full charge and test out fine. But if I’m u/w for more that 3 hours or so … I get a “low voltage” alarm on my Electronics package
Any ideas on where to start looking.

 

[wspitler]

Technically there is no "house" bank. The starboard battery switch supplies the "house" and the starboard engine. So whatever bank (#1 or #2) is selected on the starboard battery switch is powering the "house" and if properly configured, charged by the starboard engine. My best guess is the battery banks are missing a ground or have another incorrect connection. The starboard engine can only charge what ever bank is connected to the starboard battery switch and the port engine can only power/charge thru the port battery switch, unless you have the alternate charging cables that are optional and available on most Yamaha engines. Those alternate charge cables provide an additional output from the alternator on each engine and can be crossed over for redundancy. With the engines running test the voltage on each bank. Should be 13-14 VDC if charging. Select different batteries (banks) for each switch until you find the problem. Hope that helps!

 

[Danos express]

Thanks wspitler. I’m going down again this weekend to see what I can figure out. Marine wiring is such a bear when it’s not your (my) forte. I’ll follow your lead and see what I find and post …
Thanks again.

 

[SkunkBoat]

2005 330 express
1.
Had a known good shore tie cord show a “reverse polarity” light in the panel. Unplugged before energizing and tested with VOM. L6-30 plug tested correctly. Plugged back in and had NO power … checked breaker under starboard quarter .. open and closed twice, no change. Stumped

The shore power on the dock may be wired wrong. It happens...
And then it may have tripped a breaker.

I have power at my marina with two outlets. One of them gives me a polarity error light on my panel. The other works fine.
I informed the marina.

 

[drbatts]

Check to see if there is a fuse between the charger and battery. A blown fuse would explain why the charger lights up but battery doesn't charge. Also check all negative connections on the batteries, and look for missed wires since you changed the batteries recently. You are working in a hole, so sometimes a small wire gets missed Is there a another close outlet on the dock you can plug into? That may help determine if your outlet is bad.