one thing that tripped me up for a long time on my charger.
the 10ga [?] wire going from the relay to the starter was bad internally.
this happened many, many [and many more] years ago, before i knew much about trouble shooting electrical problems.
sometimes it would start, sometimes just click, click, click.
if you used a screwdriver to jump it at starter, it would turn over.
somehow, i got the brainstorm of running an "extra" wire along side of the original...............problem solved ! boogie
just something else to check. that bit me, so i'm sure i can't be the only one.
beer