Have you checked the battery voltage when it shows alot of charge ? Sounds like its overcharging. If its the electronic reg do as was said and make sure it has a good ground but also make sure the blue (12 volt) wire has a good connection. I have seen that connection bad and then the reg does not know what battery volts is and will keep charging thinking battery volts is low. With the electronic reg anything that is grounding the green wire back to the reg will make it overcharge. Ron