I called David at Annapolis Hybrid Marine the U.S. distributors for the Thoosa 9000 systems. Since the Key switch did not seem to be the issue I began thinking of other things that might easily resolve the problem. One was to disconnect the B+ of the battery to hopefully reset the controller. David said that was not necessary. I then mentioned that the power contactor relay might be bad. David ask if I had a multimeter on board. Of course I did. He suggested I remove the cover to the controller box and he could guide me on making some voltage measurements. This of course means emptying out the starboard locker and squeezing my way to large frame down below in the summer heat to access the controller box. I had not had to do this in eight years of electric propulsion operation because the system was so reliable. But, now it had to be done. I then asked a question that saved me some aggravation. In preparation of my journey down below I asked how many screws hold the cover of the controller box and are they Phillips? David replied no they are Torx (star) type screws. I did not have any Tork screwdrivers on board so I would need to buy them. But, at least I had not found this out after contorting my body down below after emptying out the locker. So it was a row back to land to get a Torx screw driver set to continue trouble shooting.
At the store I had several choices of Tork tools. The first one I picked up was a compact set that folding into the handle. It looked like it would do the trick. Though something told me that maybe I had better have a backup.
So I also bought another Torx set that had a screwdriver type handle with interchangeable bits.
Good thing I did this because I found that with the compact folding set it was difficult to access and turn the screws at the rear of the case. Where as the set with the screw driver handle was much more secure and made it easy to turn the screw. But, even then I found the controller box was just a little too close to the battery charger case to use the handle. I was however able to use just the Torx bit and a pair of small vice grips to turn the screw enough to remove it.
With the controller case finally removed I gave David another call and armed with a digital multimeter I was able to start trouble shooting. There is not much to a Thoosa 9000 system. There is of course the battery bank, motor, key switch and a box holding the controller and a few other components.
So a quick ten minutes of probing and the problem was quickly diagnosed. Compared to the hours I and some diesel mechanics I had hired in the past spent scratching our heads working on the diesel it was a breeze. Unfortunately, it is getting late in the season and I would be away for several weeks. So I had a few things to think about before I decide to move ahead with a new controller box which I'll share in an upcoming post.