I have a triple bank charger with an indicator panel on the topside of boat. It might have a more formal name than "indicator panel" but it's the small topside "plate" that shows me the charge on my batteries. When I first plug in my charger, all three indicators will show three red lights and when the batteries are fully charged, it will show green lights. My issue is one of the banks never shows a green light. I get the red lights initially on all the indicators, but will only get two banks showing green while the third is just blank. (not even showing red anymore) All three batteries are brand new. And all three batteries went a full day of tournament fishing recently so I think all three are getting charged. Any reason why I would not be getting a green light on one of my indicators?

The green LED for one bank has failed, most likely. The red LED turns off when it should, but the green one isn't up to the challenge. Check this by swapping two sets of +/- wires connected to the "indicator panel". Swap connection locations for one "good" battery, and the "bad" (no green) battery.

If the blank LED location remains in the same place after the connection wire swap, the indicator panel is faulty.

If the blank LED location moves after the wire swap, the "bad" battery is in fact faulty; it isn't reaching a voltage high enough to trigger the panel to turn on the green LED.

Are the batteries the type with removable caps? (generic add-water type battery?) If so, the absolute most accurate way to know the condition of a battery is to check the specific gravity of each cell of the battery. A specific gravity test gauge looks like a glorified turkey baster and often costs not much more than $10. (Don't get the small syringe style hydrometer with floating ball, as those are not so good.)

Thanks Flippin. Yes, it's the removable cap-style of battery. I know exactly what you are talking about with the test gauge. Will get one of those to keep on hand but can also swap out the wires to see where the problem is. Charger is about 7-8 years old.

Let me know what you discover. I'm always curious what the outcome for a problem is, but don't always hear back on it....