Jim's electric drive project for Hobbit got me thinking. I'd investigated electric drive before, when I was looking for sensible auxiliary drive for Weaverbird, but couldn't see how to work it out, so bought a Tohatsu 6HP Saildrive.
Things have moved on a bit now. It still makes absolutely no financial sense, but it does now make practical sense. As I have said before, I will never be a petrolhead, and I will always dislike having to have an infernal combustion engine aboard. Add to that the fact that the outboard well does not accept a large 4 stroke outboard very well, needing it to be left in place in the water all summer, and something had to be done. Weaverbird and I could not accept the weight of the Tohatsu on a transom-mounted bracket, and I thought that I would have difficulty starting it in that position, but an electric outboard is half the weight, and starting it is non-existent issue.
So I've started on an electrification project.
I have bought a parallelogram outboard bracket and mounted it on the transom. I am currently making up a removable plug for the outboard well, so that water doesn't splash up it and into the cockpit at speed (another annoyance I'll be glad to get rid of).
I have bought a Haswing Protruar 5HP 24v electric outboard. This weighs 14kg, half the weight of the Tohatsu. The Haswing is the thing that has become available recently to make the project reasonably sensible. It is claimed to be equivalent to a 6HP petrol outboard in thrust, but I rarely need that much. I need half an hour of full throttle motoring on rare occasions (strong tides on the UK west coast, mainly), but mostly, trickling along at 2 - 3 knots will be enough, using much less power. It's good to have the extra power in reserve, just for the occasional burst when necessary, and I will feel comfortable with using it so long as I can then wait a day to recharge.
I have bought a pair of Relion 100Ah lithium batteries to be wired in series. This is the expensive part of the project, but all the available electric outboards with integral batteries use lithium - it's the only way to get enough energy stored within an acceptable total weight. The Haswing and the Relion batteries weigh 40kg together. Using any form of 120Ah lead acid battery would make the total weight 76kg, with less usable stored energy, and I really don't feel able to lift 31kg batteries aboard and into place. The Tohatsu with a full tank of fuel also weighs 40kg. I have a sliding tray under the cockpit that has held six 10litre water containers, but I will sacrifice two of these to put the Relion batteries in the best place - low down, and as near to the motor as possible without having to make a watertight battery box to mount outside over the old outboard well.
I have bought a 360W rigid solar panel - the largest that I can squeeze onto the deck between the mast and the companionway. When I added up what I would have to do to mount a lighter semi-flexible 350W solar panel, there wasn't much saving in weight, there was a lot of fabrication to do, and the rigid panel cost a lot less. The panel will extend over the forehatch, but the hatch can still be cracked open for ventilation. I've not used it to get in and out of, so I don't think this will be a problem.
I have bought a high efficiency 20A MPPT solar charge controller, to wring every last available watt out of the panel.
I have bought a 24v to 12v step down converter, to run the existing 12v systems off the 24v battery.
I have bought a high-spec battery charger for those occasions when I go into town for stores, and shoreside power is available.
There will be some other sundries to add, but those are the major components.