Onix turns off when starting engine

I think I have read something on this before but can't find it. I have two starting batteries that are old but seem to be ok with a switch that allows me to switch between batteries or use both of them. The wiring for Onix goes through a rocker switch on the console panel. When I start the motor, low battery signal comes on showing 10.3 volts and the Onix reboots or turns off completely. Wondering if it is the switch or batteries? It is a major undertaking for this fat, old cooter to run wiring from batteries to console.

Switch is the problem

When my starting battery gets low my graft will do the same thing. More likely it is your battery.

It is recommended to wire your units directly to the cranking battery.

http://www.shut-up-and-fish.com/advanced...pce&submit=

Yep. The constant voltage drop and potential voltage spike on motor startup can damage the processor in the unit. You need a good solid connection at the battery on both terminals.

eliminated the circuit breaker/switch and wired directly to battery with a fuse. Problem solved.