How old is the charger? The newer chargers are much better at regulating and maintaining voltages. My orginal GUEST charger was cooking my batteries. Drying out the cells. My new charger has yet to cook the batteries after months of use. Highly recommend this
company for replacement charger. Made in the USA!
The unit may be malfunctioning.
The amp gauge may be defective
The battery(s) may be having a hard time staying fully charged. Perhaps a battery is internally shorted. Have you used a hydrometer to verify individual cell health? Are the cells in need of water? Use distilled and fill to the bottom of the splash guards.
Do the batts hold charge when charger is turned off for a day or 2? Perhaps there is something that is sucking DC voltage and the charger is just trying to keep up?
-Karl
1986, 32' Sedan, twin 360ci, 275hp Chrysler's w/ K&N flame arrestors