Shower sumps only working when AC converter switched on

[Skuza]

Noticed this today. Any thoughts? Batteries are charged and everything else works fine battery related. As soon as I get to the boat I turn the AC converter on to keep things charged
While there. As soon as I did I heard the pumps cycle. Tried manually filling the boxes with converter off and they fill past the switch trigger point but will not cycle until I turn the converter back on.
Suggestions???

 

[doozie]

Why do you turn the charger off, I leave it on 24/7,sounds like a bad battery,when you turn the charger back on it provides the power

 

[bahamabreisus]

agreed, bad battery

 

[Skuza]

I did kill the house bank (or whichever one the bilge lights run off of) earlier this year to the point the volt needles didn't even move. But they took a charge and everything has been fine up until this point. Batteries were new last season. I was thinking one bad battery as well but its strange everything else works.