Charger lights

Sometimes a light might go out but the charger may still be working. You can check it with a digital multimeter. After you fish for a day, check your battery voltage. Now plug that genius in and check each bank. Should be something north of what your battery voltage was on each bank. Usually 13.5 to 14.0 volts. Hope this helps.

Meters are very cheap unless you want a great one…like $20 cheap for something as easy as voltage readings.http://www.radioshack.com/search?q=multimeter

It could mean the battery is too low on power for the monitoring style chargers to read and charge. In that case a set of jumper cables or separate charger may allow the charger to bump up.