Thank you for starting this thread, Steadman, I’ve been following it with great interest. I’m
posting now as I’ve recently made significant changes to our sailboat’s
electric propulsion system and I wanted to have reliable information before sharing.
1. Please include a description (model, year, LOA, displacement,) of your boat, along with a photo of your boat, and if possible some photos of your Electric Motor installation.
1975
Dufour 34 (pic attached):
DUFOUR 34 sailboat specifications and details on sailboatdata.com
Original
electric propulsion system was 72VDC 105Ah. First
battery bank: 6 Group 31
AGM (Westmarine-branded Deka
batteries, pic attached), they lasted about 5 years (poor to marginal performance after the third year). Replacement
battery bank: 6 cheaper deep cycle flooded
batteries, 4 of which I had to replace within 2-3 years as they died prematurely (very poor performance as traction batteries).
System was converted to 48VDC this year replacing the flooded batteries with two light-traction Lead Crystal battery banks (four batteries each). Dramatic improvement in range, amazing technology (I have no association with this company). It required replacing the battery
charger as Lead Crystal batteries need significant amperage to be charged properly.
2. What was your total cost for the conversion?
See next point
3. Compare the total cost of replacing your old Diesel or Gasoline engine with an Electric Motor. The more you can share with us, the more helpful it will be.
Conversion was done 9 years ago (this is our 10th sailing season with electric propulsion) at a cost of $4,200. Later I added a 2000W portable
generator ($600) to increase range. I designed and built the system, cost reflects only
equipment and materials, including about $1,000 worth of batteries.
The second battery bank (generic flooded batteries) was about $600.
The
current Lead Crystal batteries (8) were about $3,400 (including shipping) plus $350 for the new battery
charger. Pic of one of the two banks attached.
We could have bought a brand-new
diesel engine, had it installed, and paid for years and years of
fuel and
maintenance based on our annual
consumption for less than what we have spent in electric propulsion so far, and it was
money well invested (note: we knew from the initial stages that electric would be much more expensive).
4. Describe the process and why you did the conversion.
Besides not liking the
noise, vibration, fumes and
maintenance associated with diesels, we couldn’t justify polluting the
environment to enjoy sailing (to those tempted to lecture me on the pollution generated by electric propulsion, as in many other similar posts, I hope they find a better use for the time).
At the time of the conversion there was very little information available on performance, in particular related to range. We knew this was the main drawback, however we’ve always been the last boat to drop
sails when the
wind died and the first ones to take advantage of the slightest breeze, motoring much less than other sailors in the area. We don’t mind sailing or motoring at slow speed (and we never missed the diesel engine).
Limited range proved to be true, 10 to 15 miles at 2.5-3.0 knots in favorable conditions with lead batteries, much less with headwinds and or opposing currents (we sail in the Upper Chesapeake Bay).
After deciding to try electric, Yahoo electric boats forum was an amazing resource. I opted for an ETEK RT (MARS ME 0709)
motor matched to a Kelly PM 36-72V-400A controller (Pics attached, both have performed flawlessly) and a QuickCharge 6-bank battery charger (pic attached). The
motor is mounted on an
aluminum frame with reduction
gear that acts as a heat sink (the controller is mounted on a heavy-duty heat sink, however it never gets hot). The traction unit was designed to facilitate replacing gears if needed (not the case so far, even when switching from 72V to 48V and from a 2-blade to a 3-blade prop).
5. Describe any changes you made to your battery bank. At what cost or weight added to the boat?
Initially we considered
LIFEPO4, however they were too expensive for our
budget. As mentioned before, we started with deep-cycle AGMs, hoping that
LIFEPO4 would become cheaper when having to replace them (hasn’t happened yet). These batteries proved to be not suited for traction. As LIFEPO4 remained very expensive when we needed to replace the AGMs, we tried generic flooded deep-cycle (they were even worse than
AGM in terms of performance).
Golf cart batteries were an option I discarded due to weight and space, in hindsight it could have been a very good idea.
We decided to replace batteries for the third time this year seeking to extend range, I explored LIFEPO4 again, flooded and AGM golf-cart batteries, premium deep-cycle AGMs, and newer technologies: Firefly Oasis (extremely expensive glorified deep-cycle AGMs IMHO) and Lead Crystal. I decided on the later and after a couple of months using them I am constantly amazed with their performance.
For those contemplating electric propulsion: batteries are the critical component. If considering an alternative to LIFEPO4 and traditional lead batteries, I’d like to share some information about Lead Crystal (again, we are not related to this company, just happy customers): they are safe (I understand the only batteries that can be transported by air), suffer extremely slow self-discharge (each battery arrives with a sticker with the date they were last charged, in my case 5 months earlier, and each of the 8 batteries showed the same voltage: 13.14V), can be discharged to literally zero Volts without being damaged (although they go from 10V to 0V quite rapidly) and can remain partially charged for very long periods of time. The downside is that they require significant amperage for
charging, and suitable chargers are few, which is the reason I installed two banks instead of a
single, higher capacity one (I charge each bank individually with a 48V-30A charger, a 60A charger is not viable for my application).
Charging is super-fast compared to lead batteries. In terms of range, I expect at least 30 nm at 3.4-3.6 knots (to be confirmed) under normal conditions (range decreases exponentially with speed). Finally, Lead Crystal technical and sales support are top-notch, they worked with me tirelessly selecting the best configuration for our system.
Weight: with one 72V bank using Group 31 batteries, total weight was 200 ponds less than the diesel system we replaced (an old and heavy
Volvo MD7B, diesel tank and ancillary equipment). With the
current configuration (eight Lead Crystal 6-EVFJ-100) we added about 100 pounds compared to the diesel system, however the second bank is located near the center of the boat and the overall impact is negligible (I guess it even improves stability).
6. Describe how you recharge your batteries. Are you using shore power, Solar or a Generator?
Shore power, and a portable generator for the AGM/flooded batteries to extend range. As the portable generator cannot
power the new battery charger, I’m considering
buying a 48V DC generator to increase range if needed.
Unfortunately, so far we have not been able to regenerate under sail, Kelly Controller's technical support (also great) has been working with me on this for a while, I think it is related to
wiring, on the to-do list.
7. Describe how much range you get from your Electric Motor system. Has it been sufficient? What about during adverse conditions such as opposing winds, waves, and currents?
Besides opposing winds, waves, and currents, speed is a key factor (and a clean bottom/propeller).
We used to get 10-15 nm @2.5/3.0 knots with 72V-105Ah batteries (fresh batteries, one bank) and complemented with the generator when needed to motor longer distances.
Current configuration: we expect 30+ nm @ 3.4-3.6 knots with two 48V 115Ah Lead Crystal banks and longer distances at lower speeds (technical note: Lead Crystal traction batteries are rated at 10h discharge rate, while regular batteries are rated a 20h discharge rates). I'll post an update on this in a couple of months.
8. Describe your type of sailing (marina based day sailing, long distance cruising). Does your typical use of your sailboat require you to motor much or little?
Mostly day sailing/weekend sailing, and several week-long cruises each season. Electric allows us to sail all year (if temperature is above 50!) as there is no need to winterize the system.
9. What motivated you to convert to Electric Motor?Describe whether you made the conversion as an experiment (so total cost was not an issue) or if you felt it was justified by some kind of economic comparison (e.g. you felt it would save money in the long run) or if you did it for some other reason (e.g. you want to have a "green" boat that does not use fossil fuels).
The main driving force was to have the greenest sailboat possible, and as a second benefit eliminating noise/vibration/smell/fumes/maintenance associated with diesels. We wanted to
experiment with electric propulsion for a long time (since we had to re-power our previous sailboat almost 20 years ago),
we never expected to save money compared to replacing with another diesel engine.
10. Describe any challenges you faced during the conversion or later, during the operation of the Electric Sailboat.
The system has performed flawlessly since turning the switch on for the first time over nine years ago. I estimate we’ve sailed well over 6,000 nm since converting to electric. Range limitation is a very affordable
price to pay for almost silent motoring, instant
power, no maintenance, no winterization and, as a bonus, the looks of people staring at us when they see our sailboat moving with no
sails and making no
noise, priceless!
11. Post any tips or suggestions you would make to anyone considering making a conversion or purchase of an Electric Sailboat.
Electric propulsion is not for everyone or any boat. If you need to motor for long distances, regularly confront adverse conditions (strong currents, headwinds, choppy seas) or just like to motor at high speed, diesel should be a better option. Also, if our boat would have been bigger/heavier I wouldn’t have converted to electric. Although there are plenty of bigger boats with electric propulsion, in my experience our boat is at the borderline in terms of power requirements/battery capacity.
12. Would you do it again?
Absolutely. Every time we motor my wife and I comment on how beautiful it is to move silently and how happy we are with electric propulsion. I’m currently looking for a traditional launch to convert to electric.
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