If you bought your 30 day old alternator because the old one wasn't charging
, and if the new one isn't charging, the problem is probably somewhere else. Probably wiring
or a ground. Or if the alternator has a outside voltage regulator
, that could be it. Most better auto parts
stores will check an alternator or voltage regulator
for free. If they test ok, it's somewhere else.
Also, the voltage at the battery
when running should be about 14.5 volts. You might hook up a meter and go thru your tack experiences again and see what voltage readings change.
Knowing nothing about your tack or engine type, variable readings could be caused by low voltage. Gas engine tacks usually count distributor spark and most newer diesels have a small generator
like device that sends signals to the tack. Both need reliable voltage.
on any cables
or wire ends are common on boats. I would check both ends of battery cables
by removing them at the posts and where they attach to the engine and starter. Clean the ends and their contact point.
A problem I had when a alternator tested ok, was corrosion
traveling down the main cables. Somehow the starter could blow thru the corrosion, but the resistance was enough to stop the charging current
. When I cut open the cables there was the green corrosion you usually see at the terminals.