Sometimes I forget that the size of boats most people have here are relatively small compared to mine. I have one of the 3 41' original Lagoon Catamarans that were constructed with the Solomons Tech electric system. Most of what Eric says is correct for smaller boats that are running strictly electric motors with no backups other than the sails. I've not been able to understand the use of 24v or 48v systems until I remember that again most boats can't handle the 144v bank weight that I run. Or the fact that I have regenerative props and a 15kw genset on board as a motoring backup with limits only set by the number of gallons I carry. Yes this isn't a pure electric when I have the genset running but then again I don't need to run it much anyway since the props are generating 5 or 6 amps back to the bank on an 8 knot sail but I'm burning 1/2 the emissions by only having 1 motor. I still haven't spent over $100 on the genset (1st oil change and fan belts this weekend o joy) so I figure I'm ahead of the game for the time being. Money spent on the electrical has been more towards the monitoring and balancing then on main components to extend the battery life as long as possible on the 12 AGM's. Triple the estimate that Eric has below and you're in the ball park of what the system onboard Electra Glide would cost. Here's the thing. I do get 3 hours (50% battery) at 6 knots on batteries alone and, for the Chesapeake Bay, that gets me off the dock, SAIL ALL DAY, and back onto the dock with typically as much power as when I started. Last year I burned a total of 12 gallons of diesel and sailed almost every weekend from April to November. The boat is 7 years old and the motors and system aren't hardly broken in when you look at 100,000 hours of expected life.
When we look at these systems, all of them, we have to remember that this is cutting edge technology using fairly old systems. There really isn't much that has been improved on over a very long time. It's the car and boat guys willing to experiment with these pieces that has moved the systems being produced in packages to the market. I'd be the first to admit that the success of these systems is highly dependent on what your expectations are and how you use them. There are people out there that are looking for the perpetual motion machine that's going to give them endless power to move their machine and it just ain't out there. However if we can be a little quirky and operate outside the bubble then we might find something that works based on how we use it.
Lithium's are great batteries and probably the best thing out there at this time. I wish I could afford them but I estimate that it would be roughly around $22,000 in batteries at this time. I'll double my run time, double my life time, 1/3rd the charging time, at 3 times the cost and add a battery monitoring system to be sure I don't exceed the mini/max parameters which are a more demanding. Cost averaging over the 10 years they should last looks good but I can't spend that kind of money at this point. I'll learn and hope to extend the life of the AGM's for another 5 to 8 years and see if the prices get down to affordable. Yes I know this could replace 1 of my motors but I need 2 and added maintenance costs over that period puts the batteries at an advantage.
So here are a few more of my thoughts..
If you're contemplating electric drives think hard about your worse case scenario. In most cases you're going to want a genset backup and a TowUS card. The genset if you are going to exceed the battery pack hours and TowUS if you have a complete meltdown. This compares to an ICE machine running out of fuel or having a meltdown of the ICE.
If you're running in a canal for hours on end and can't take advantage of anything other than a power pole at a local dock this isn't your best bet.
If you're on a lake and want to go 100 knots more than 10 minutes then this isn't your best bet.
If you're planning on crossing great oceans or cruising under battery alone we're just not there yet unless you have huge amounts of deck area for solar panels or wind generators. I'll mention again that one of my sister boats did cross the Atlantic with excess power generated from the props only. They ended up running the air conditioners because the designer forgot to tell them what to do if this happened.
A genset as a backup power supply makes sense IF it's used as a backup and safety is a priority. If you have a single electric motor boat and run the genset all the time it doesn't make sense. Wasted energy and all that in converting that energy.
On the other hand...
If you can get into open water and hoist a sail within an hour this could work for you. Add solar panels, regeneration, or a wind generator and sail all day. Add a genset and you can go anywhere.
As with those who have converted to EP you either love it and it works for you or you wished you hadn't had this great idea to convert in the first place. You didn't look at your usage before jumping into an infant technology. Even the car guys are looking at the same issues. How come I can't go forever on a single charge? Because the batteries can't provide enough power and you want to go to fast is the usual answer. Know your limits and what your expectations are and you will be happy with this technology. Expect otherwise and you're going to be sad. It's that easy.
One last thing, Eric, I for one thank you and others for the technical stuff that I only 1/2 understand most of the time. I've learned a lot from you guys here and truly appreciate it. You're a realist and I'm a dreamer. I'm hoping to do the Delmarva Peninsula this early fall if all goes as planed and hope to do it without the genset running, regeneration and sail only is the goal. Might not happen in the canal at the top but we shall see.
Steve in Solomons MD
John,
I agree with your recommendation for Lithium batteries, I have a 48V x 160Ah battery bank in my sailboat.
But, you also included a key metric in your post. The Lithium batteries alone will cost $8000 and all of the Cruisers Yacht VillaVee boats that I saw listed for sale cost between $7000 and $9000. All of these boats seemed to be in good shape.
I believe that the twin drive costs including chargers and the rest of the conversion would exceed $8000 without the batteries. I can't believe that many owners would want to spend more than twice the cost of a replacement boat and reduce their top speed by 75% and their range to less than 2 hours.
Honestly, would anyone here spend their own money on a project like that?
Fair winds,
Eric
Marina del Rey, CA
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