tom wrote:
On May 6, 6:21 am, wrote:
Why do you have the solar charging both house and start batteries??
If there is nothing other than the starter drawing of that battery,
why charge it.
You're most likely going to kill it.

I have solar and wind. They go only to the house bank.
The start battery only runs the windlass and starter.
I gets charged by the engine (running) and dockside.

The engine and house are the same size (100ah), I only
have 2 and just use them together, it's not a separate
smaller starter battery.

So you actually have one bank with two batteries.

I had an opposite problem - low voltage issues that affected starting
over the years. The final diagnostic that clarified everything for me
was the old "screwdriver across the starter terminals" trick. My
problem was that the "neutral lockout" wires that went back to the gear
shift before feeding the solenoid were too small so the solenoid didn't
always get enough voltage to trip. One thing is that I thought I heard
to solenoid tripping but it was something else clicking - this became
clear when the screwdriver test showed that the solenoid was perfectly
willing to fire when it had sufficient voltage.

WARNING: the "screwdriver test" send a lot of current through the tip -
it will likely be charred and there will be many sparks.

This problem is more perplexing because a high voltage generally cures
more problems than it creates. I can only guess that one of the charge
devices is actually a drain in some situations.