My Experience with EV – Part 7 Wiring

After the motor was installed I was under a time crunch to complete my EV drive before the weekly beer can race on Lake Union, Duck Dodge.

I only had a few hours, so I didn’t take very many photos, but I did install and wire my contactor, controller, gages, and key. I followed the diagram shown below. After all was installed, I hurried to the local ORiely’s to pick up three more cheap marine deep cycle battery to match one that I had purchased in hopes of resolving Yanmar starting issues I experienced prior to the winter sailing trip Ava and I wen on.

Hurdle 1 – ORiely’s only had one more battery. Oh well, my controller will work on 24v. I bought the one thinking we should have enough juice to get out of the marina and go for it.

Hurdle 2 – My PC would not recognize the the controller to program it for my motor. This issue was a simple one, restart my PC, gotta love windows USB to Serial Drivers.

Hurdle 3 – The controller sends error signals when the throttle is activated. This was a wiring issue of the potentiometer. To solve the issue I had to contact Curtis Controls who directed me to one of their dealers who explained how the potentiometer should be wired. This step was not completed until the following day, we missed Duck Dodge but proceeded to drink some beers and grill some brats at the dock and enjoy the evening.

Hurdle 4 – After the batteries were connected and I heard the contactor make a solid “click click” as I turned the key on, but still received a low voltage error code from the controller. I was told that the contactor was not meant to work with 24V, so I needed to buy two more batteries. Back to ORiely’s I picked up the final 2 batteries for my 48V system and hooked everything up.

Hurdle 5 – Still receiving the low voltage error code. More back and forth with Kelly Controls (Fany was very helpful) only to determine the wiring of the coil on my contactor was incorrect (although it followed the schematic on the website). Once I grounded the coil properly, everything worked! Instead of hearing the “click click” I simply heard a “click”. This step took a while as I was sent to Australia for work for a month.


Wohoo! The Manta Drive is Alive!!

Up Next, Sea Trials on My Experience with EV – Part 8.

My Experience with EV – Part 6B Finishing the Motor Mounts

My plan to mount the motor beneath the floor boards took a turn for the worst. The motor wouldn’t fit once connected to the CV joint.


It was time to rethink my approach and consider Plan B. Plan B was to mount the motor above the propeller shaft and drive it off pulleys. This would place the motor directly below the last rung of the companionway ladder. While the motor would not longer be hidden below the floorboard and a direct drive, I sat back to think about the benefits.

  • The motor is out of the bilge and not not under the risk of being submerged
  • Although I will be losing efficiency due to a belt, I gain the ability to gear the motor to better match the propeller
  • The poles of the motor will no longer be close to the floor and will not cause an electric shock hazard

Not accepting defeat, I changed gears and came up with an idea of how I was going to mount the motor. I was going to fiberglass in vertical stringers between the hull and the floorboard, to the stringers I would mount angle brackets and atop the angle brackets I would bolt the mounting bracket. Simple, right??

At the end of the day, it should look something like this.


After glassing in the stringers, I painted and epoxied some angle iron I picked up from the local recycle yard for $0.88. Notice in the photo the drive pulley is already on the prop shaft, what a PITA to install.


After I secured the angle with stainless lag bolts, I drilled the angle to accept the aluminum cross-member which I also picked up at the local recycle yard for $4.00. After a bit of discussion on the forums, I decided to place some rubber pads between the angle iron and the aluminium plate to further prevent galvanic corrosion and allow for some flexing. Thankfully I had an old mouse pad laying around that I was able to cut into strips and place between the dissimilar metals.


I then drilled holes for the 4 bolts that would be used to align the motor to the propeller shaft. In order to tension the belt I decided to use longer bolts and “float” the motor on nuts much like the leveling of a coinventional refrigerator.


Here is what the motor looks like fully connected. All that was left was to cut the floorboard to make room for the motor and take her for a test spin!IMG_3733

So simple, sleek, and elegant!

Follow along on My Experience with EV – Part 7 for the wiring details.


My Experience with EV – Part 6A Motor Mount Mods

As of my last post, my plan was to mount my electric motor below the floorboards to open up the cabin layout. This would allow me to better utilize the space within the boat for living aboard. This dream was FOILED!

Here is what happened.

After I mounted the sprocket on the motor and bolted it to the CV joint I quickly learned that the motor would not fit below the floorboard! Earlier when I had tried it, I did not have to motor attached to the CV joint, and once I did, the motor would no longer fit. I tried rotating it, I tried moving it around, no dice. There was one angle that would allow it to fit, but it proposed several more issues that I was not willing to deal with.

  1. The motor would not be aligned well, this would translate to excess wear on both the motor and the CV joint and excessive noise.
  2. The poles of the motor would be VERY close to the floorboard, being that the floorboard was intended to be aluminum plate, that could translate to a 48V electric floor.
  3. The mount would be a challenge to fabricate, and the motor would be very challenging to install and remove. Having worked on several older cars thinking “why did they put that there, don’t they know it may need servicing one day?”  made me realize that It was not a good idea.

Back to the drawing board, this was frustrating, I had a self imposed timeline that I would not meet, and one last Duck Dodge that I would not make prior to leaving for a work trip to Australia for a month. But the ever optamist that I am, I quickly changed gears and came up with a new solution. The motor would now mount below the entry steps, and spin the propeller shaft by way of pulleys.

There were a few advantages to this setup, so all in all, it was not a loss.

  1. The battery poles were no longer close to the floorboards, and did not create a case for an electric floor.
  2. The mount would be easier to create, and would allow for some flexibility in assembly/removal.
  3. Now that I was no longer running a direct drive, I could play with pulley sizes to get a more ideal RPM at the propeller (though there will be loss in the system due to the belt).
  4. The motor would no longer be in the bilge – no more risk of submerged electric system.
  5. It would force me to learn another piece of the boat that I was scared of – propeller shaft packing.

The new plan:

I was going to fiberglass in some wood pieces between the floor and the hull vertically. To these mounts I would bolt two short pieces of angle, and across the top, I would bolt a piece of aluminum plate. In the plate, I would use bolts to make adjustable motor mounts so that I could easily tighten/loosen the belt and properly align the motor.

In order to make it work, I would first have to remove the transmission coupling from the propeller shaft so that I could put the new pulley directly on the propeller shaft. According to the forums, this can be a daunting task that may include cutting my propeller shaft!

I decided to start with what I knew, I cut 4 pieces for wood to fit between the floor and the hull and sealed the wood with epoxy. After the epoxy cured, I glued the wood to the hull and the floor, and screwed them to the floor.

Once the glue cured, I came back across with fiberglass matte to make the mounts rock solid. Pro tip – cut the fiberglass matte to manageable sizes, and wet it out on wax paper before applying to the area. A good reference for this is a video from the folks as Sailing Uma found here. It is very important to completely wet out the fiberglass matte. Fiberglass has this uncanny ability to wick moisture into the entire matte from a single strand of dry exposed fiberglass. Since this mount is below the floorboards, there is a slight chance of moisture, and I don’t want my motor breaking the mounts free.

Now, onto that propeller shaft. Before I started disassembly, I had to first educate myself on how they work, how they are assembled, and what I needed to watch out for.

YouTube turned out to be the best source of information, and this video turned out to be very useful in giving me an understanding on how/why they work, and how they are assembled. The forums were filled with horror stories about how difficult the are to disassemble and how most people just end up cutting the shaft and starting fresh – an option I was not too keen on.

After some search, I came up with a plan to remove the coupling. First step was to remove the set screws on the caliper and loosen the hose clamp backup. Then I would pry the shaft apart from the CV joint and insert and socket between the coupling and the CV joint. I would then tighten the coupling and CV join back together and the socket would press the shaft out. This process worked like a charm, but was a serious PITA and took a couple hours, a video of my efforts can be found here. After getting the coupling off, I sanded off the rust and slid the new pulley on the shaft and reassembled. The reassembly was straightforward, but light sanding was required on both the shaft and the coupling.

Back to the motor mounts, I went on a hunt for some aluminum angle and plate. I ended up in South Seattle at a scrap yard where I was able to buy the angle cut to size along with the plate for a less than $10! Unfortunately, the angle was steel and the plate was aluminum, left to their own devices the two dissimilar metals would undergo galvanic corrosion, essentially eating each-other away. To combat this, a coat of paint and epoxy was used.

I took extra precaution against the corrosion, and cut up an old mouse pad to place between the two metals as a “rubber spacer.”

I screwed the steel angle to the fiberglass mounts I made with 8 hearty stainless steel screws and the mount was rock solid. After the plate was bolted down, I set the motor on top to mock up the mount and size the belt I would need.

I needed a 28″ B series belt, which I sourced from O’Riely for $11. The end result looked something like this:


Woohooo! The motor is mounted, time to make those electric connections!

Follow along for My Experience with EV – Part 6B for the end result of the motor mounts.


Go Go Gadget… House Batteries!

Blue Sea System, sailboat power supply

It was winter time and thus it was project time, I had already torn out my chart table and was under mid construction when I decided to keep tearing things apart!

I left the Cinderella unplugged for two days and I had killed the house batteries. Granted the AGMs are nearing 20 years of age, but Ava and I sailed to Vancouver and through all of those islands without running out of juice for days, what gives? To answer the question I had to do some crawling.

Chart Table

Do you see that Aluminum box in the left corner of the screen? Well behind that box (the fuel tank) lived the batteries. You couldn’t see back there without a flashlight, and a gain it took a gymnast to get anywhere near that setup. I was frustrated in short order. What do I do when I get frustrated? I tear things apart. Out with the tank, out with the batteries, and out with the old breaker panel! It was time to bring Cindy’s electronics up to snuff.

Ericson 35-2 original breaker panel

The old breaker panel not only was in the most inconvenient location, but it left plenty to be desired. So I did some online shopping and landed on a new panel from Blue Sea Systems up in Bellingham, they had the best price for what you get, and a great customer care department that shipped me a new breaker when one was damaged during installation.

I knew I was going to have both a 110V AC circuit and a 12V DC circuit, and with plans to leave the country, I was not overly focused on 110V, but I knew I needed something for the next two years. I settled upon a uit that had 15 DC breakers, and 5 AC Breakers, the panel also had a voltage meter for the AC shore power, a ammeter for the DC system, and a battery voltage monitor for up to 3 batteries banks. The ammeter really opened my eyes to how much electricity a single light bulb can draw, LED is the future.

Blue Sea System, sailboat power supply

I had a box laying around that came from a gift I was given from my sister and her boyfriend in Vancouver. It turns out, the box fit the panel almost perfectly, it even had hinges, which would allow me to gain access to the panel in case I had to troubleshoot or add new functionality. A few minutes with the dremel, and it fit perfectly.

When I tore the old panel out, I also moved the batteries. There were previously under the sink and taking up valuable space that was going to be a water tank. I made a frame out of scrap wood I had laying around and mounted the batteries below the port settee. Along with moving the batteries, I also move the selector switches and the charge controller to a more user friendly location, below my desk.


After I spent countless hours going through all of Cinderella’s wiring and routing it through the new panel, it was time to play with the switches. When I was flipping the switches, I noticed something very alarming, the running lights drained a lot of juice!

When I flipped on the running lights, I saw the meter ammeter climb to nearly 15 amps, for 3 light bulbs! No wonder I drained my batteries after a full two days of sailing. Fortunately several advances in technology have happened since the 70’s, and in the category of lighting we have advance substantially over the past 5 years.

I walked down the street to Fisheries Supply and bought new LED alternatives to the bulbs that were in the boat. Not only are LEDs substantially more energy efficient, but they also last much longer, as they have no filament to burn out.


After replacing the light bulbs, those same three lights hardly made the needle of the ammeter budge. I would say lighing is the most substantial upgrad you could make in terms of energy efficiency in a boat.

Pro tip – you can buy many of the new LED bulbs online these days at a fraction of the cost.


Ahhh, the feeling of a job complete and one less thing to worry about!

Combating the Moisture

As I have said before, the moisture here in the PNW is rough on liveaboards. As much as I love all of the snow we get in the mountains and the incredible skiing that is a direct result, the condensation that forms on bare fiberglass is a bit much to handle. Insulation was at the top of my list.

First we must ask, why does condensation form? To answer this, lets think of a glass of ice water on a warm day. It has everything to due with relative humidity and a thermal gradient (temperature difference). When water in the glass is cold, and the air around it it hot and full of water, the glass will actually draw the heat out of the air surround it, after all thermodynamics tells us everything want to hit equilibrium. The glass pulls the heat from the warm air surrounding it, and with it comes the moisture. When the air is humid enough (contains enough water) the water in the air undergoes a state change, it becomes a liquid! Water vapor in the air condenses and it condenses at the point where it contacts the thermal gradient (the glass). That same principle is working against you in a boat. There are three means to combat moisture, and only one is passive i.e only one will work without and work being added to the system. That one is to add insulation, think adding a coozie to the glass. The thermal gradient is reduced due to the insulation properties in the foam coozie, thus preventing insulation. That is what I will do to my boat. For the record the other means to combat condensation are airflow and dry heat.

If you remember from the original post, Cinderella was taken down to bare fiberglass hull she was raced to Hawaii in the Pacific Cup.

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I had my work cut out for me. What kind of insulation should I use? Where do I find it? How much do I need?

I quickly resorted to what I know best, google, to the forums I went! It turns out that boats intended to be used in cold weather usually have a layer of foam sandwiched between the fiberglass of the hull, but how do I emulate that?

I found another blog outlining one mans attempt, it seemed to work well for him, so I thought I would give it a whirl. The plan, glue 1×1 stringers to the hull, cut foam in insert between the stringers, cover with “ceiling.” For some reason boat walls are covered in ceiling and the “roof” of the boat is usually covered with a headliner.

For this project I went to my local Loews and picked up Reflectix and Polystyrene home insulation. Reflectix is basically bubble wrap with foil which is very easy to work with and makes almost no mess, however the main insulation property of Reflectix is radiant heat, I wanted to also combat conductive heat. To combat the conduction heat, I decided to use polystyrene, polystyrene is “closed cell” so it is impervious to moisture and therefore mold. I chose to sandwich 1/2″ polystyrene foam between 2 layers of Reflectix. Polystyrene is messy to work with, pieces of foam go everywhere and stick to everything when you cut it.

The end result made such a difference! No more damp boat!

I started by gluing in the 1×1 stringers which the ceiling would be affixed.

boat insulation, sailboat, insulation

I tried several types of glue during this process, regular silicone, liquid nails, and gorilla glue construction adhesive among others. Considering I once glued a propeller back together in a pinch using gorilla glue and it held up, its no wonder it turned out to be the best candidate here. For the stringers I used pressure treated 1×1, these are commonly used for porch railings, so I would skip the “marine grade” and save some $$.

Pro tip – the shorter you cut the stringers the better, especially if your hull has a very sharp curvature.

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The foam was then glued to the hull in between the stringers. Again I can’t speak highly enough about construction adhesive! To glue the foam layers together I used 3M spray on adhesive, it was a quicker way to cover lots of area, and worked very well.

Once the stringers are glued in and the foam is inserted, its time to add the ceiling. Classically, sailboats used wooden slats that interlocked with each other and are stained to prevent moisture intrusion and add to the aesthetic. I, however don’t have the time to wait for stain, and I don’t want to bother with cutting so many boards, I want to stop the moisture now!

That was when it hit me, flooring! Flooring is meant to take abuse, and is usually highly water resistant, and you can buy it ready to lock together, stained and ready to go, perfect! Thanks Bob Villa.

Boat ceiling, insulation, Cinderella, sailboat insulation

Again I put my trusty Ryobi kit to work and before long, Cinderella had a whole new look!

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Of course I had to place the wine box into the photo to highlight my progress.



A Modern Chart Table

Awkward spaces, much like bright red colors, they play tricks on our minds. Shrink those spaces down, and its like amplification. What once didn’t seem to bother you, starts to scream.

As you can guess, Cinderella had a few of these spaces, and my mind was about to explode. The biggest was the chart table. Cinderella had a chart table that was 26 x 26, you could draft at the table. It was awkward to stand in front of, it made stowage impossible, and worst of all, it made my head explode. Something had to give.

Chart Table

Notice the chart table is up against the bare hull, making for no storage and no usable space. There is a quarter-berth tucked behind it, but anyone short of a gymnast had no buisness attempting to get in and out of it. When winter in the PNW rolled around, the bare fiberglass started to sweat, dampening everything and making things exponentially worse. Out she went.

I felt like Tim the tool man, sawzall in one hand and hammer in the other. The plan was to remove the table and hopefully use the pieces to build a new one, one issue, how do I mount it? Its against the hull, and I’m not drilling into the hull…. I guess it’s time to learn this whole fiberglass thing.


Here is an image of the chart table in use. It’s hard to tell in this picture, but all of that space aft of the table is clutter. Clutter that is prime to drive the mind wild in a small space. Another thing to note, the table is at an angle, nice when standing next to checking charts no doubt, but awful stowage, and worse when the boat is heeled on her starboard side. Let the demo begin.

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It was not long until I was at bare hull.

Only problem was that support was far too high for the desk I was going to install. I pried it off of the hull and lowered it about 10 inches. I used the West System 105 epoxy and hardener. For the connection to the wall I used their 405 fillet compound. The idea is to make nice rounded joints where the board meets the hull so the fiberglass sheet doesn’t make a sharp 90 degree bend. Holding the board in place prior to fiber glassing presented its own set of challenges. I ended up using Gorilla Glue construction adhesive with great success. once the glue hardened, I started to lay the fiberglass.


The hardest part was waiting  for the fiberglass to dry! It was winter in the PNW, not that it gets too cold, but the condensation on the bare hull was impressive. Thankfully, the west system epoxy will cure even if wet.

Once the main support board was in place, I went ahead and cut the desk to its new size. I settled on an “L” shape with a slight angle.


The top was easy to cut, the challenge would be deconstructing the rest of the old chart table and constructing the new one. Also, what about the space just aft? My desk needed a seat.


A jigsaw and a scribe were used to cut the plywood in a curve. and it worked remarkably well! The question was, what height should the desk be from the bench?

After a bit of research, 14″ seemed to be the sweet spot for seat to desk height, so I went for 16 assuming I was going to but cushions on the seat.


Due to the strange shapes involved, I just made the bench piece by piece. This was not one of those “measure twice, cut once” scenarios. I knew I was going to need stowage under the seat, so I cut out openings. for access panels.


After all of the panels were cut and fitted, I pulled the seat back apart and epoxy sealed every panel. Remember I said that winter here are moist? well wood + moisture = mold and I want to avoid mold at all costs. I used acetone to thin the epoxy mixture so that it would easily paint on and went over the boards with a few coats. After I reassembled the bench, it looked something like this.


I decided while I was at it that I would buy one of those nice new Blue Sea Systems breaker panels in the boat. The previous panel was in a hard to reach place, wired in order to keep wire runs to a minimal, and usability to the spartan. Cinderella was to be my home, and I needed to be sure my home had functionality of all her systems.


I mounted the panel in a box with hinges so that I could open the panel in case I needed to replace a breaker or add new wiring along the way. The best part was, I already had the box from a gift my sister and her boyfriend had given me during our Vancouver Sailing trip! Thanks Eric and Danielly!


My Experience with EV – Part 5 Motor Mounts

As I said earlier, one of the biggest perks to an electric motor was being able to open up my floor. Previously, in the middle of my cabin was a large coffee table the hid the Yanmar. Now that the Yanmar is gone, I decided to oust the coffee table as well. The new electric motor will be small enough to fit under the floor boards, so time for some renovation!

Cinderella’s Yanmar Diesel engine space converted to house the new tiny motor drive. We call him “Ol’ Sparky”



The first step was to break out the saws and cut away the fiberglass bed that the motor mounted to. This turned out to be a serious PITA. Lots of sweat, saws, and beers later, I had cut the old mounts away. For the record, the sawzall was the best tool for the job, I cut the fiberglass with a dremel and followed it with the sawzall. Any fine work I did with the Ryobi all in one, it’s easy to handle and can cut any of the funky angles. Of course, various pry bars made the process much quicker as well.

The fun thing about this boat project is that all of the tools I own are aboard along with all of my belongings (after all I do live on the boat), so I tend to get crafty with the tools I have to complete the job. I have not come across anything yet that my $250 Ryobi cordless set can’t handle.

After the engine bed was removed, I was left with a hole in the floor, which was no good. Fortunately, someone at the marina had decided to tear up his old teak deck and throw it away! New floorboards were free.

I was hoping to make the floor flush, and my Ericson has a slight downward angle in the floor which I had to account for when I was cutting the boards to fit. I decided to make the floor in 3 panels. The first panel would be made of wood (free teak), the second and third panel would be made together and later cut into separate pieces. Because the second panel was also to be the new electric motor mount, I decided to make a template out of cardboard to use when I get the steel/aluminum panel that the motor will mount to.

After cutting the board and cardboard to fit, I wrapped them in wax paper so I could use them to bed the fiberglass I will be using to make the floor flush.

Cinderella, Ericson Yachts, Ericson 35-2, Manta Drive, Electric Sailboat

Fiberglass is easy to do once you get the hang of it, but it really takes a toll on my patience! Fortunately, the controller hasn’t arrived in the mail yet, or I would be chomping at the bit as I watched the fiberglass dry.

When they installed the engine, they did me a great service and aligned it using a CV type joint rather than directly connecting the transmission to the propeller shaft. What this means for me is that I don’t have to worry as much about aligning the motor perfectly and the thrust from the propeller won’t damage my new electric motor. I just have to make/find a coupling to convert the CV flange to my electric motor’s 3/4″ shaft.

I inquired at one of the local machine shops and was quotes $300! No way was I going to spend that kind of money on a little piece of metal, surely there was another way. After work, I drove down to the local bearing shop and found a sprocket that mounts to my motor, and fits into the bolt pattern of the CV joint, and for a mere $27! One last mounting challenge, I need to find a steel or aluminum plate that I can transfer my cardboard template onto and use to mount the motor to the floor….

Follow along on My Experience with EV – Part 6 as I finish up the motor mounts.

My Experience with EV – Part 4 Buying MORE Goodies

While I sit here anxiously waiting for my parts to arrive, I decided to sit down and draw out a wiring diagram for what my system will look like. Kelly Controls has a recommended wiring diagram on their website for their controller, so I started there and added a few things specific to my system.


First off, I wanted a key to turn everything on and off, to keep people from jumping on-board and taking Cinderella for a joy ride without my permission. I also wanted a buzzer and a fan that will kick on if the motor got too hot for any reason. And because amazon is at your fingertips, I bought a couple of meters to display the battery percentage, the amps being drawn, the battery voltage, and the total energy used. This should make the system look a little sleeker and give me feedback on how it’s running. The wiring diagram also called for a resistor, a diode, and two switches (one to enable regen, and one to go between forward and reverse.)Electric Sailboat, Manta 2, Manta Drive, PNW Sailing, Cinderella

After a few hours comparing options, I hit the bank account for another 30.62 bringing my total to 638.97.

The last components required are a throttle lever and 3 batteries. This should be another ~$400.

This should bring my total cost of the system to 1038.97, or 1588.97 excluding the engine sale. Not too bad considering I was expecting $1700 overall. Before I get too excited, let’s wait and see how it goes.

Follow along on My Experience with EV – Part 5 for adventures in motor mounts.

My Experience with EV – Part 3 Buying the Goodies

After loads and loads of searching through online EV forums and watching videos on YouTube, I decided to take a chance on the Manta 2 DC permanent magnet electric motor. I was able to find the motor and an adapter plate on EBay for a cool $463.35 with tax and shipping ($60 above my estimate, but I also purchased a mount). Wohoo!! It’s happening!

Right around this time, I managed to sell the Yanmar for $550 to a friend who is building up his own sailboat, an Islander 30. This is big, as it will offset ~ 1/3 of the cost to repower Cinderella. I could have parted out the engine and probably broken even, but the time and care involved was not something I wanted to take on.

So, I have a motor, but what about the rest? I needed a controller, what’s a controller, how do they work? Back to Google. Let’s simplify controllers, they are a means to “control” power flow into an electric motor to vary the speed of your motor. Otherwise, you have either full speed or no speed. Which, as you can imagine is not ideal when trying to maneuver in tight quarters.

Classically, DC motors were controlled by resistors. Resistors simply take the energy going into a motor and burn it off as heat, therefore reducing the energy going to the motor. Nice, simple, right? Wrong! “Burning off” as heat translates to poor efficiency and also adds heat to electronics which substantially shortens their life.

Enter the controller, the controller plays upon the concept of Pulse Width Modulation or PWM, a fancy acronym for a simple concept. Basically a microprocessor (think computer) controls a series of switches (kind of like really small light switches) which open and close very, very quickly. When this happens the stream of energy going to the motor is stopped, then started, then stopped, then started and so forth from those switches. The end result is a means to speed up and slow down an electric motor without excessive losses.

That’s great, but I still don’t know very much about controllers, which one do I need, what do I need to watch out for? I am after all pretty new to all of this.

More research, more google, and I landed on a company called Kelly Controls LLC. Kelly Controls makes controllers for all sorts of applications, for both AC and DC motors. Kelly Controls have a couple of benefits that set them apart from the others: cost, programmability, reverse, and regen ability.

The controller decision was possibly the most challenging so far. There are a handful of major brands: Alltrax, Curtis, Kelly, Sevcon and a few others. I only know this due to the EV forums, which spoke highly of Alltrax, Sevcon and Curtis, but had mixed reviews of Kelly.

From what I could tell, most of the major EV sailboat kits out there utilize Sevcon controllers. Why did I land on Kelly? Well after speaking with a few of the companies, I was told that their controllers “Don’t do regen” with PM motors. They also don’t reverse internally, I would need to buy another $200 component to make that work. Bummer! The decision was simplified, Kelly Controls it would be.

Controllers are rated by two basic numbers, Amps and Volts, sounds an awful lot like high school physics. Both of these components are defined by the motor and battery bank choice. Amps, or the measure of current through your system is the limiting factor for all things battery.

Batteries are rated in Amp/hrs or the amount of current that they can provide for a set amount of time. Remember I said my electric system in the boat pulled about 20-30 amps at 12V? That probably means little to anyone that hasn’t had a refresher in high school physics, but it simply means I can run my electronics for about 10 hours before I need to charge the batteries. The same concept applies to my electric motor, the only difference is that the motor will use a higher voltage, and the amp draw will vary with how fast I want to go.

After comparing Cinderella’s system with that of other conversions, I will hope to run Cinderella between 20 and 60 amps. That translates to speeds of about 2-4 kts or roughly 2-5 mph for those non-boaters.

Knowing this, I should be able to motor for 1 – 4 hrs on my cheap batteries and 2-8 hrs on the ideal Oasis Firefly’s. But the Fireflies will last a lot longer and can take more abuse between charges, they are the ideal battery. Motoring slowly, I should expect about a 30-40 mile range which is sufficient to allow Cinderella to get through the locks and into the Puget Sound (1.5 mile trip), remember I plan to regen under sail, and will eventually install solar panels. This should allow for plenty of summer sailing fun while I get my funds in order to upgrade before I make the trip around the marble.

Alright back to my controller choice. I will be running Cinderella’s motor at 48V, so I have one of the numbers figured out, what about the Amps? I told you I plan to run the motor at 20-60 amps right? Well the motor is capable of 100 amps, and from what I read, you want at least 50% head room to keep the controller running efficiently (why they don’t rate them practically is beyond me). This narrowed my search down to a 48V 200-300 Amp controller capable of regenerative braking. I also wanted the controller to have the ability to reverse the charge to the motor which will allow me to reverse without buying more components.

With those stipulations, I settled upon the Kelly Controls PM48301, a 300A 48V controller with Regen for $349. Along with the controller I purchased some fuses to protect the wiring, a contactor to allow for an on/off key switch, and a heat sink to help keep the controller cool in the tropics. The total purchase price was $695 with shipping.

This brings my total to $1158.35 if we subtract $550 for the engine I sold, that figure becomes 608.35. Not too bad, I’m still on track with my budget. I still need batteries and a lever that can convert my boats throttle lever into an electrical signal that the controller can recognize.

Follow along on My Experience with EV – Part 4 where I buy more electronics to get Cinderella electric.

My Experience with EV – Part 2 Planning Time

Electric, Sailboat, Propulsion

Out with the Yanmar! On to craigslist it went. A few months prior I started watching some sailing channels on YouTube, one of which was Sailing Uma. I would highly recommend this channel and their website here, they have loads of do it yourself information, and are just inspiring to watch.

The inspiration for the electric drive came because of a few episodes Sailing Uma did about going electric.  It looked clean, simple, and absolutely great! My interest was piqued. Conventional wisdom would tell me “battery technology isn’t there yet” “you won’t have much range” “electric motors are fine on flat water, but what about wind and waves”

That last one that really hit me hard. If there is wind I will… SAIL! After all, Cinderella is a sailboat, and we do intend to SAIL around the world. So I started researching, lots of researching.

Unlike internal combustion engines, I had no experience with electric motors. I didn’t even know how they worked. Are there different kinds? Which is best?

This took me down a path that lead me all the way back to Nicola Tesla, inventor of more electric gizmos that I realized. After lots of articles, a book, My Electric Sailboats, and some searching of the various electric vehicle forums, I was convinced. Electric is the way of the future, and oddly enough, it was the way of the past.

Electric, Sailboat, Propulsion

I began by calling around the local scrap yards and electric motor shops here is Seattle to try and source a cheap, used electric motor. No luck. To Ebay!

I was eventually persuaded to small permanent magnet electric motors in the 5000 – 7000 watt size. Due to the limited capacity in batteries and the cost of components, 48 volts was the goal, which would require 4 batteries. There are a slew of battery options out there, which to choose?

During one of my many stops at Fisheries Supply, I was handed a business card for Alex and Jack Wilkens at Seattle Boat Works. It’s amazing how tight knit the boating community here in the PNW really is, and everyone seems to be trying to help each other out.

I gave Alex a call the following week. I told him of my plan and asked for some advice. Alex was really helpful and after I sent him Cinderella’s specs, he happily did some calculations and gave me a rundown of what I should expect of my proposed system. Alex was really up to date with battery tech and gave me recommendations . It boiled down to really two options, use a conventional AGM system or a bank of Oasis Firefly batteries.


Ultimately, I hope to go the route of the Oasis Firefly, but cost unfortunately is keeping me away from them at the moment. I have way too many projects on my hands with Cinderella already. In the meantime I will make do with the tried and true cheap ol’ lead acid marine deep cycle batteries, 4 of which should cost about $400 and I already have one compared to the $2000 of a Firefly system.

The picture started coming together, let’s take a look at the expected cost:

Motor – $400

Controller – $400

Batteries – $300

Charger – $200

Misc – $300

Total – ~$1600

All in all, not too bad considering the cost of a new diesel engine is ~$7000 and this has the prospect of “maintenance free” operation which should simplify things considerably. I could also fit the motor beneath the floor boards in Cinderella which would completely open up the cabin! No more obtrusive coffee table.

I was also excited at the idea of regenerative breaking, or the ability to charge my battery bank with my propeller while under sail. According to the web forums, this is theoretical, and I shouldn’t expect much, but Alex at Seattle Boat Works said he saw as much as 7 amps  at 48V DC going back into the batteries while under sail, and only at 4 kts! I was intrigued.

I have an idea of current draw from installing a fancy Blue Sea Systems electric panel in Cinderella. Cinderella draws about 20 -30 amps of 12V DC while underway with instruments, lights, ipad charging, fridge, stereo and stove on at any given point in time. Granted this is a rough estimate, but by switching to LED for running and interior lights I have room to dramatically reduce my current draw, and while under sail I can offset a large portion of this without any solar or wind!

Follow along on My Experience with EV – Part 3 where I buy expensive electronic things.