Attempting to check out a charging system without an accurate voltmeter and ammeter is a total waste of time. The ammeter on the dash is just a rough guesstimate of what's going on, and an idiot light is even worse. If the battery is staying charged and the light is on, but dim, there is a high resistance connection somewhere. You're going to need to find someone with enough electrical knowledge to be able to measure the voltage drop at every connection between the generator and the battery, which eliminates virtually all automotive hobbyists, and at least 90% of the so-called professionals in the auto repair trade.
Jerry
