Electric Propulsion Update

[Jimske]

I guess there is a good reason why this thread died? EP doesn't work?

My Searunner 31 Trimaran is up for sale but I still think about electric propulsion. If nobody buys it I would seriously consider doing some kind of retrofit if it made sense.

I currently have an OB (9.9 Yam). Why can't I keep the OB, install an electric drive and use the OB for back up AND charging the battery bank? The thing about the 31er is that it is light and it is a rather simple install there being ample space below the stern double. For my purposes that would be a good solution if feasible. I am not overly concerned about fuel consumption. The OB is quiet as a mouse and already keeps the battery charged. If some day there were more green cost effective solutions to fossil fuel back up I would be ready to go.

So a small electric motor could move the 6000# trimaran along on it's own at low "trolling" speed or combined with the OB would give it plenty of additional power in more demanding situations.

Thanks, Jim

[JRM]

Originally Posted by capn_billl

Not trying to disparage, just pointing out that unless a turnkey system professionally installed, with field support, you will need to do some electronic troubleshooting to make it work.

Disparage away. It's not like we haven't all heard it once or twice. Heck, if the "old salts" could accurately prognosticate, I'd die some horrible death every time I leave the dock in our electric auxiliary sailboat. I can't wait for the gnashing of teeth when I convert the Valiant in a couple years...

I'll have to echo Mike's experience, except that I had some professional help getting the gearbox and shaft aligned. The electrical stuff is the easy part, although that may be because my kit included the cable harnesses. That's one of the reasons I went with a proper system in the first place instead of rolling my own. After *tons* of research on building my own, I came to realize that the only way I could beat the price of the turnkey system apples to apples was if I didn't make a single mistake in purchasing or installing (and even then it requires some luck). The mechanical parts of DIY are tenfold more difficult than the electrical bits (for me, anyway).

If I had it to do over again (and someday I will since we upgraded in boat size), I'd go the same route, except that now I'd probably have a lot less assistance in the mechanical stuff, as I've gotten a lot more comfortable with things boatish since then.

JRM

[JRM]

Originally Posted by Jimske

I guess there is a good reason why this thread died? EP doesn't work?

My Searunner 31 Trimaran is up for sale but I still think about electric propulsion. If nobody buys it I would seriously consider doing some kind of retrofit if it made sense.

I currently have an OB (9.9 Yam). Why can't I keep the OB, install an electric drive and use the OB for back up AND charging the battery bank? The thing about the 31er is that it is light and it is a rather simple install there being ample space below the stern double. For my purposes that would be a good solution if feasible. I am not overly concerned about fuel consumption. The OB is quiet as a mouse and already keeps the battery charged. If some day there were more green cost effective solutions to fossil fuel back up I would be ready to go.

So a small electric motor could move the 6000# trimaran along on it's own at low "trolling" speed or combined with the OB would give it plenty of additional power in more demanding situations.

Thanks, Jim

You should head over to the Yahoo! groups electric_boat group. There's a bigtime eboat guru dude over there who owns both a 30' Cheoy Lee and a dragonfly trimaran. He's converted the Cheoy Lee, but says that weight wise it doesn't make sense to do the tri. You still can't beat petrol for energy density. I would imagine that the moment it becomes practical to convert the lightweight trimaran that he'll do so. That moment has not arrived yet, which should be telling...

JRM

[deckofficer]

Good to see this thread is alive again. Some changes during that time, the biggest being the drop in LiFePO4 cell prices. A 700 a-hr Winston cell going for $462. Balqon - Advanced Transportation Solution

Also I've assembled the components for a electric kayak that runs 80 nm on 60 lbs of LiFePO4.

Since LiFePO4 have come down in price, it is now viable (meaning over time the cost is absorbed in fuel savings) for the typical Caribbean motor cruiser to convert to solar-diesel-electric. An easily propelled boat like the PDQ 34 PowerCat at 15,000 lbs displacement, equipped with 75 KW-hr LiFePO4 bank, 2500 watts of solar, could cruise the Caribbean's typical 100~125 nm island hops on stored solar energy. A sunny week at an anchorage would fill the battery bank allowing for a stately speed of 4.5 kt for a 24 hour run. Total cost of conversion, motors, controllers, solar panels, and LiFePO4 cells would run $25K, and before you say it, yes $25,000 would buy a lot of diesel, but after just 2 1/2 years of 6500 nm per year of cruising, that expense is covered by the lack of fuel expense and from that point on your ahead of the game.