[C320-list] Low Voltage

[Pat Tormey]

This was a little odd, so I thought I’d share.

The issue was low voltage everywhere except the battery tester voltmeters and the cockpit voltmeter.

The first symptom was loss of the GPS signal internal to the iCOM VHF followed by flickering of the Garmin chartplotter. It first started after running all day while transiting the NJ shore NYC to Cape May last fall. I solved the momentary issue by lighting off the motor, though the batteries were reporting good on the meters.

On the return trip (Solomon’s MD to Newport, last week) the autopilot would reboot instead is engaging and the chartplotter would reboot,  again after a long day, with or without the engine spinning.

In port, my VOM was reading 10.9 volts across the positive and negative busses behind the electrical panel indicating either a bad ground OR a bad battery switch.  

Both battery meter indicators were 12.7 V to the negative buss with means the ground was good. Apparently, the ‘sensor’ wires do go thru the switch but directly to the battery.

Switching the battery switch 1,2 or both didn’t move the needle. So, it had to be the main breaker (next to the battery switch). 

Removing the panel, I found the terminals slightly corroded and one was bit loose. I cleaned and tightened. However, I also cycled the breaker a few times so I can’t be sure which action restored the voltage. 

I’m sure a bad breaker will announce itself. I’ll order a spare.

Pat

Pat Tormey 
s/v Blue Skies