[Oldsguy]

Doug, it sounds to me like you have your voltmeter set up to measure current, not voltage. Measuring in series between the negative cable and the battery (I hope you mean the negative terminal on the battery) will be a setup for current only, you should read no votage at all. Are you sure you didn't have the setting on the voltmeter on current? Usually indicated by a straight dash for dc current or a curved dash for ac current. The test light is a current indicating device which by ohms law means that there must be a voltage difference of potential between the two points being measured if the lamp is illuminated. The way you described your set-up, if you checked for current and had a positive indication then that would be an abnormal result. Under normal conditions your alternator should not draw current (drain voltage) from the battery when the engine is not running.