Our electric motor had functioned flawlessly for years, until we added a new step in the system: the generator. While the manufacturer states that running the motor while charging is fine, I think it might have been the culprit!
See, the manufacturer claims that it is acceptable to do, but they have a nice and fully functioning charger. On Wisdom, we have a half dead hand-me-down that we got for free, and I suspect that it is the problem.
It all started when we were in Hatteras and decided that the North Atlantic during winter gales is not a place we wish to sail. We changed our plan from crossing the Atlantic in October to "Sail to the Bahamas and cross the ocean at the correct time of year." We bought a Honda 2000 generator to allow us the ability to charge the batteries while away from a pier. Before we left, I performed a test (which I feel was the first nail in the coffin for the charge controller). Wisdom was plugged into shore power and the charger was running. I hypothesized that if we ran the motor at 14 amps, we would be able to run indefinitely since our charger puts out 15 amps. We carried out the test for about 14 hours straight. The charger kept pace with the motor and when the test was concluded, everything was shut down to reveal that yes, the batteries were still full charge and the motor ran entirely off of the charger. Success!
Then we motor sailed away from Hatteras and into Oriental, NC. We were there for a week and decided it was time to move on, but the motor had a different plan. It was dead and completely unresponsive.
I called the manufacturer and spoke directly with the builder of the motors who walked me through the diagnostics which led to the discovery of the dead controller. The manufacturer then sent out a replacement controller and off we went!
We continued motoring down the state of North Carolina for a few months (we are slow) until we were nearing the NC/SC line when the motor began alternating between forward and reverse on its own! We were moving forward, and the shaft was being viciously tossed in alternating directions with the full strength of the motors. We contacted the manufacturer again, and the tests once again concluded that the controller died. They sent us a new one and also sent us a spare one since we had plans of cruising internationally.
I installed the new controller and everything seemed to be operating just fine, but we decided to make a rule after some thought. The motor needs to be off when the charger is on.
Yes, the manufacturer insists that you can charge and motor, but I think our charger may have a fault that is killing the controller over and over. We have replaced the controller twice (and still have the spare in a locker) and have had no problems since we implemented this rule.
Our future plans include a new, properly functioning controller that will grant us the luxury of motoring while charging, but in the mean time, our mysterious issue seems to be resolved.
I am aware that per proper experimental models, I need to reintroduce the charger while motoring and see if it kills our controller. The truth is, the controller is annoying to change and I would rather not have to do that again, so I have yet to properly reintroduce the variable.
If you are considering electric propulsion, or have electric propulsion and are considering adding a generator, I would suggest contacting the manufacturer of your electric motor and buying a new charger per their recommendations.