Electronics gurus: Theory on false Overheat - AR210

[ripler]

Even if the battery is showing that it is fully charged on a multimeter it can still be bad, you can have an auto parts store do a test on them. When I had my Yamaha I had a battery that showed fully charged on a multimeter and it actually started the boat, but it had a few bad cells in it. When the boats charging system tried to charge it the regulator/rectifier on both motors got so hot that it melted a few pins on the connector that plugged into the regulator/rectifier. You want to talk about a troubleshooting nightmare. I ran the same setup that you have in my Yamaha for the 10 years that I had it and had zero issues with it, my philosophy is to keep it simple, a DVSR just adds another failure point.

 

[knoxboatin]

@ripler that's a story from hell wow.

 

[TimW451]

I don’t think the switch is bad, I think it may be wired wrong.

@FSH 210 Sport yes, batteries are the same and new with the boat last spring (2021). This is the setup.View attachment 185639View attachment 185640

My theory arose out of it working fine with battery #2 (nearest the switch) disconnected. Since bilge is wired to that, the bilge switch would not be seeing any voltage at all with the battery disconnected. So no conflicting information.

I only have a cheap multimeter so voltage only shows something slightly less than 12 on both.

@TimW451 I could try taking the switch out of the path, yes it is something related to the new arrangement since it ran fine with them in parallel last year. The switches are pretty dumb and mechanical so not sure what the failure mode would be. I bet the 1 & 2 setting would work fine also, since that joins the batteries together. Kind of defeating the purpose but at this point just tired of the false alarms so I am still suspecting the electronics sense some difference between the two batteries and complain. I can deal with it as-is but I had slow-rides back to the marina on one engine a couple times due to worrying about BS overheat warnings unfortunately.