Help, please. I changed over to 12 volts with a GM single wire alternator patched into the old wire loom and still using the ampmeter rather than a volt meter. Now if the truck is not started and run every day, in two days the battery needs to be re-charged. The ampmeter shows charging after the initial throttle blip to "excite" the alternator, but something's not right. How do I fix this? TIA