Ask PYS: Power

Reverse Polarity Light and a Portable Generator, on Oct 05, 2016 asked:

I'm up here in Prideaux Harbour and tried to charge my batteries and can’t. I have a Yamaha 2000 watt generator connected to the shore power - it worked with the old charger. However when the generator is connected, the 120 volt reverse polarity lite comes on (always has). Is the new charger sensitive to this, thus causing the charger to cut out? Is there a fix for this? - Dieter

The reverse polarity light can mean two things in this situation: 

1) AC hot and AC neutral are swapped; or

2) Your AC ground is floating and therefore there is a voltage differential between AC neutral and AC Ground

 With a portable generator it's common for the AC ground to be floating.  Does this problem occur when connected to shorepower?  The charger might cut-off because the new charger is taking more power than the Yamaha generator can provide. As a test, try to run the Yamaha Generator and charger when the batteries are nearly full. That will limit the charge rate and could help us identify the issue.  - Jeff