Recap #2 of our Stink Pot Journey May 1st - 4th ’22

Fri Jun 10 2022

We equipped JollyDogs with LiFeP04 batteries back in 2014, along with a massive solar array. Living in the sunny Mexican environment as well as French Polynesia, we enjoyed true energy independence, almost never having to supplement our solar charging with fossil fuel generated power. Sunset is a different animal entirely, with a different type of power systems architecture. This boat was built with a single 8D starting battery, a single 8D deep cycle “house” battery, and a pair of 8D deep cycle “inverter batteries”. House battery loads are everything that runs off DC which includes the refrigerator/freezer, diesel furnace, nearly all the lights, and a pair of smoke/CO detectors. New, these 8D deep cycle batteries are rated at 240 amp hours, which means that at best 120 amp hours are available for use. In truth one can only rarely top the batteries all the way up and the capacity degrades with age. The rule is that 50% depletion, or about 12.2 volts (no load) is as low they can go without suffering damage. Conventional lead acid batteries won’t efficiently charge like LiFeP04 cells, so a lot of the charge input is wasted and topping them takes a long generator or propulsion system run. Sunset has a mix of Interstate and Dyno deep cycle batteries; Dyno says to charge at 14.3 volts and consider them fully charged at 12.6 volts while resting.

Our pal Bill Bressler loaned me his battery tester back in April and all the 8D batteries tested good. The generator start battery tested weak so Costco swapped us the core and some cash for a new one. The dinghy engine start battery also tested good - it was replaced in April ’21. My intentions had been to live on the pontoon as if on the hook for a couple of days to evaluate how things really worked without shore power, but that effort was overcome by events. Our departure from Port Townsend was the beginning of our shakedown cruise, success oriented of course, and our first night on the hook up at Stewart Island’s Prevost Harbor revealed just how dismal flooded lead acid batteries are compared to LiFeP04. It was cold and rainy and between running the diesel furnace and some lights the house battery was flat in no time. Boiling water for tea with the electric kettle while using the inverter powered by its 2 batteries immediately set off a low voltage alarm. As Sunset is an all electric boat except for the BBQ grill, it seemed the generator was going to get quite a workout.

Conversations with Bill and Chris helped us understand that a single house battery ain’t much so we elected to put the big clank switch in the “Both” position. Always combining the batteries was apparently what the previous owner did and it did help the situation, allowing us to get through the night with the furnace kicking on occasionally. We eventually realized that even though the low voltage alarm was going off during furnace start up (glow plug briefly energized) and when boiling the kettle (massive load) once the load was removed the voltage would generally recover to above 12.2 volts. Recall 50% depletion is noted at 12.2 volts resting, so how is one meant to set alarms on a simple battery monitoring device?

This was all new and wonderful, as the LiFeP04 batteries which were rated fully charged at 12.8 volts generally demonstrated a resting voltage of 13.2 volts and rarely dropped below 13.0 volts even under very heavy loads like the electric kettle. With good solar input we could run the hot water heater or the kettle or the water maker and still charge the batteries up, but we did have a massive 1440 watts of solar in a tropical sun environment. It’s amazing to note how well a single sideband radio broadcasts with a 13.2 volt input.

So we were in cultural shock given the difference in daily power management, and in doubt of the battery tester results. Prevost Harbor had a lousy cell signal so we moved over to Roche Harbor on San Juan Island where T-Mobile cell service was excellent. Calls to battery vendors and a good bit of internet digging later, we concluded that we would just press on to Canada and continue monitoring the situation. Either things would improve or we would be beaten into submission.

We had one strange and memorable event at Roche Harbor. Firing up the generator first thing in the morning didn’t work out too well, as it soon overheated and shut itself down. Gee whiz, I had just replaced the raw water pump and almost no water was exiting the exhaust. Fearing the worst I opened up the cap to inspect the impeller but it was fine. Next I pulled the heat exchanger input side apart and found no debris. Opening the cap of the raw water strainer revealed a giant glob of grease partially blocking the flow, but removing it didn’t correct the situation. Next I removed the hose from the thru-hull to the strainer but it was unobstructed. Finally I opened up the thru-hull valve and noted a really weak dribble of water coming in. Somehow, something was blocking the raw water hull inlet or the valve itself. Perhaps more grease? Anyway, fashioning a tool from a piece of wire I verified no blockage in the valve, which only left the external thru-hull inlet screen. With the water in the low 50’s F there was going to be no swimming as we might have done in French Polynesia, so we finally tried firing up the starboard engine and creating a load of prop thrust in both reverse and forward to circulate water over the thru-hull inlet screen. We had to be careful as we were still on the hook but darned if this procedure didn’t work. Seaweed can be evil stuff, apparently not just preventing a good anchor set.

Next step - off to clear Canadian Customs!