The question would be whether you still have the infamous trailer connectors in the wiring between the panel and the engine.
In my opinion, it's all substandard - bad connections in the trailer connectors, bad connections at the starter and alternator, poor quality inline fuse holders, non-tinned wiring, wiring of insufficient guage, and so on.
I finally bit the bullet and replaced all the wiring between the panel and the engine.
The alternative is to firefight as problems present themselves, which they will continue to do.