rewiring charging system

Please don't "simply" do that. Read this article, carefully. Please

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

In other words inspect and repair the bulkhead connector, "at the very least." I would jumper the wire to the starter relay and not the starter itself

While you are at it, at least check, and upgrade the engine -to- body grounding.