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Installing an electric motor

20K views 84 replies 29 participants last post by  SailingCinderella 
#1 ·
Has anyone installed an electric motor in a boat that originally didn'y have an inboard? It's just an idea but I was curious I anyone had done it. I have a Helms 25.
 
#48 ·
While most believe a standard trolling motor is too small to qualify, using a higher output trolling motor actually is pretty reasonable. I'm running an 86 lbs thrust trolling motor and find it works very well. In a true comparison, being that Bianka is only pulling 15 amps, I assume at 48 volts, that would be like my motor pulling 30 amps at 24 volts. Wide open, with the boat not moving, I will pull about 50 amps. So power wise, I would view it as one class down from that setup.

The setup is very simple, and have less than 400 bucks tide up in motor and batteries. Thrust wise, it works very well. You just can't beat electric. It is so much easier to control, especially when docking. The boats tend to stack up at the launch ramp, so the instant on is very nice. No sitting idling while waiting in line. Very dependable. Just twist the switch and you are moving. One reality demonstrated in Bianko's videos is the silent operation. For days with no wind, being able to ghost along provides nearly the same level of relaxation as being under wind power.

The OP's boat weighs around 4Klbs. My boat weighs about half that. It would be pretty simple to connect up twin trolling motors. Total cost less than 800 bucks, which would be considerably less than any other electric option. I saw a post of someone who used a 55 lbs thrust motor on a Mac 26D. He stated top speed was around 3 knots, so that combination is on the small side.

Hopefully there is enough info for one to gain a pretty good idea of what would work and how well.
 
#51 ·
Oddly enough, my leaf uses a 12 volt car battery for lights, stereo, cell phone charging, etc. It also uses the 12 volt battery to start up the electronics that control the car... So..and you will laugh at this... If I leave the lights on and it kills the car battery I need to get a jump start, even if I have a full charge on the lithium ion batteries that power the motor.

The lithium ion batteries will charge the old school car battery (through, what I guess would be called an inverter) as long as I can turn the damn thing on.

I have also used the car battery to hook up ye olde jumper cables and jump start internal combustion cars in need.
 
#52 ·
I guess the answer to the OP's question is, "it depends." I'm approaching EP from a slightly different perspective and am interested in others thoughts.

I intend to buy a new boat, probably in the 40' range if all goes as planned. So technically, I'm starting without an diesel engine too. I have always been of the mindset that the boat would be equipped with both a diesel engine and a diesel generator. The latter because it's more fuel efficient and more optimally designed for power generation vs the diesel engine (which doesn't like running at low RPMs).

The ramifications are two engines to service, two areas I have to squeeze into and then I started thinking about all the different aspects of a diesel engine's servicing: Raw water strainer/thruhull, exhaust, Fuel filters, Oil Filters, Oil, Spark plugs/glow plugs, Engine belts, Alternators, Impellers, Water cooling pump, Spare hoses/fuel lines, antifreeze, winterizing, reduced diesel tankage, Engine insulation, Bilge blower, Engine related tools, Engine mounts, Starters, etc. Now, in all fairness perhaps not all of these will be negated but they all have a cost and most play a role in servicing a diesel and deserve consideration...including time (frustration) away from the things we all prefer to do when we're on a sailboat.

I read a lot of posts criticizing EP. The main criticisms tend to revolve around it being untested, unreliable, black box control units and the biggest criticism, range. However, that latter isn't a drawback of EP. That's a battery issue and it's clearly becoming less and less of an issue as battery technology improves. Gradually I arrived at the realization that a properly spec'd generator can effectively negate all range issues, and now that the early adopters are posting their experiences, unreliability and lack of testing are no longer an unknown as far as I'm concerned.

In spec'ing a system I would chose a prop that maximized regeneration. yes, that leads to more drag but drag can literally be turned off by running the EP at a very low draw. With solar and wind gen, both of which I originally intended to have, this becomes a non-issue. When I'm not in a rush to get somewhere (it is sailing after all), for the price of EP I also get a nice hydro generator added in for free. Since EP consumption is logarithmic, the faster you go, the more amps you draw and it goes up quickly. I'm thinking a bigger motor should equate to less draw for a given SOG. Not sure on this and would love others input.

Now for the upside: I would have one less engine to service, a motor I could easily remove/replace on my own if necessary (brushless motors require almost no maintenance from what I've read), nearly silent propulsion for shorter distance motoring and with a good generator unlimited range and quieter operation vs a diesel engine while using less fuel. Far less parts to carry and less time spent servicing/cleaning = more free time and less frustration. Plus, a better torque profile vs a diesel engine.

I'd probably offset some of the parts costs with a backup controller/black box but replacing those looks like a breeze compared to major failures associated with a diesel engine. I anticipate it would be weight neutral at worst when you consider an additional battery bank. Speaking of which, I think I would probably have a smaller house bank and leverage the EP bank when/if needed so I would anticipate some $/weight savings there as well. Last, I think the cost would be comparable to a new diesel engine and all the additional items a boat must have to facilitate it's installation. Actually, I think it would be less, but let's assume it's cost neutral.

Plus, if you believe battery technology is going to vastly improve as I do, you would then have a boat that's more compatible w/ future EP tech AND even more range without using the generator.

Some companies I've found in my search: Auxilia, Elco, Electric Yacht, Electroprop, Oceanvolt, Propulsion Marine, Tema, Thoosa and it looks like this space will grow....

....that's where I'm at right now.
 
#54 ·
Some companies I've found in my search: Auxilia, Elco, Electric Yacht, Electroprop, Oceanvolt, Propulsion Marine, Tema, Thoosa and it looks like this space will grow....
Hi I'm still in exploring and spec'ing stage myself - and clearly see the advantages over a 35 year old Atomic4.

I found ElectricYacht to be quick to respond to request for technical info and specific application for my boat. I learned a lot from info they provided. I'm sure others would step up as well...
 
#55 ·
Opc,

It's doable. The major limitation is going to be speed under power when running from the generator. A generator sized for house loads is going to provide far less power than a 40' will need for propulsion purposes. A generator specced for propulsion will provide far more power than you will need for house loads. The best option is probably two DC generators that can be run one at a time for house loads and paralleled for propulsion.

This isn't terribly efficient, but at least you get an electric drive.

Alternately you can go with a massive battery bank that can handle high charge rates and provide enough power to run the house for a day or more. So when you turn on the generator the batteries can accept the excess charge and get back to full pretty quickly.
 
#58 ·
Thanks for the feedback. BTW, I've stopped usingopc and now use PSea. I completely agree about the ease of access to a generator. Id spec it to fulfill propulsion. I can't ever see charging batteries quickly being a drawback.

Am I off base in favoring a larger EP motor due to elec consumption not being linear? Ie Less amps needed for higher speeds?
 
#59 ·
The problem is a generator specced for propulsion on a 40' boat needs to be about 25kw or so. This isn't peak demean dust typical cruising speeds. Slow down substantially and you can get away with less.

Now size a battery bank capable of accepting this charge rate. It isn't as easy as it sounds.
 
#60 ·
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#61 ·
Um... No.

A reasonable energy usage of a 40' sailboat at cruising speed is roughly 13.5hp or about 11.1kw. To convert this to 12v battery power you would need 11 of these toys. But this is just cruising speeds, no head wind, no chop, no problems. And fla batteries do not accept bulk charging rates at a high enough C to handle this massive influx of power. So either the battery bank has to be massive, or you need to swap to some other chemistry.
 
#62 ·
um, i was only supporting his choice of generators and matching his voltage and rating. Two in series would be 36 volts, which is what his motor runs on. I was not making commentary on the over all power to push his boat.

BTY: I'm not sure your calculation is completely accurate on how much power to push his boat at a reasonable speed. I don't believe you would need to hit full hull speed to be practical. If you can hold 4 knots into a 30 mph headwind, you have enough power. On days with no wind, that would likely add 2 knots or more - fast enough to be practical.
 
#63 · (Edited)
um, i was only supporting his choice of generators and matching his voltage and rating. Two in series would be 36 volts, which is what his motor runs on. I was not making commentary on the over all power to push his boat.

BTY: I'm not sure your calculation is completely accurate on how much power to push his boat at a reasonable speed. I don't believe you would need to hit full hull speed to be practical. If you can hold 4 knots into a 30 mph headwind, you have enough power. On days with no wind, that would likely add 2 knots or more - fast enough to be practical.
I do not believe the hobby grade Hobby King power supplies are meant or designed to be run in series. Some lab grade supplies can be run in series, they are specifically built & wired for this, but cheap ones often can not. At the worst, depending upon internal AC/DC wiring, you could create a short and kill one or both of the power supplies.

I have had some awful junk from Hobby King and also some egregious knock offs that don't do what the real branded product will. I bought two Junsi Cell Log 8S units that were not Junsi nor were they the 8S data logging model. I bought a few LiPo batteries and the cells were not even close to being matched for capacity, or impedance, nor did a few of the cells hit their mAh rating. You need to be real careful with Hobby King and know exactly what you are getting. I really don't think I'd want to depend upon a Hobby King charger to keep my expensive vessel batteries charged. These are short intermittent-duty products for charging small 4-10Ah LiPo, LFP or NiMh batteries.
 
#64 ·
I had no specific experience with that brand. To run those in series, you may have to lift the ground, and/or isolate the case. Switching supply should be isolated from the AC line by the transformer.

One comment I would say about running any EP setup. One should have extra cables on hand at all times to bypass the motor control. If for some reason the smoke escapes from the controller, you don't want to be stranded. You also don't want to be stuck running full speed. You should have enough wire on hand to run the batteries in any kind of series/parallel combination, so that you can approximate the speed you need.
 
#65 ·
One comment I would say about running any EP setup. One should have extra cables on hand at all times to bypass the motor control. If for some reason the smoke escapes from the controller, you don't want to be stranded. You also don't want to be stuck running full speed. You should have enough wire on hand to run the batteries in any kind of series/parallel combination, so that you can approximate the speed you need.
This would work for motors like my LEMCO brushed motor. Indeed some boats used contact switches to provide power to the motor. I'm not sure if newer AC phased motors would allow for jumper cables as a backup though. But, it is a feature that is available to get one moving should controller electronics fail on brushed motors. Though after eight years I can say my EP system has been pretty trouble free and have never had to go to any backup plan.
 
#68 ·
They're whole project on the boat is pretty cool. At least they seem to be having fun. Their EP install, they took the long way around the barn trying to use a fork lift motor thinking it could be bolted up to their old ICE transmission. They should have just bought a packaged DIY kit from one of the EP vendors out there, in my opinion. Don't know if they've posted any recent adventures.

Had a bumper sticker in my office back in the 80's.
"A short cut is usually the longest distance between two points"
I think in their case, it was.
 
#72 · (Edited)
I'm seriously considering an electric solution. it's odd how these discussions get mixed. the electric motor works wonderfully well. the issue is the power source; batteries and the ability to keep them topped up.

my solution is a diesel generator which I intended to have even if the boat had a diesel engine. so the way I see it, I get rid of one engine, all the spare parts and all the maintenance, reduce weight, and increase (quiet) enjoyment since I don't need the generator running as often as I'm running the electric motor. add in solar and wind gen plus a big prop sized to serve as a hydrogenerator and you have unlimited range....subject to the size of your fuel tanks, wind and sun or combination thereof.
 
#73 ·
I'm seriously considering an electric solution. it's odd how these discussions get mixed. the electric motor works wonderfully well. the issue is the power source; batteries and the ability to keep them topped up.

my solution is a diesel generator which I intended to have even if the boat had a diesel engine. so the way I see it, I get rid of one engine, all the spare parts and all the maintenance, reduce weight, and increase (quiet) enjoyment since I don't need the generator running as often as I'm running the electric motor. add in solar and wind gen plus a big prop sized to serve as a hydrogenerator and you have unlimited range....subject to the size of your fuel tanks, wind and sun or combination thereof.
I'm in my ninth season with electric propulsion and you are right in your assumptions. When I did the conversion back in 2008 there were not many boats who had ditched the diesel. I went through a lot of "what if" scenarios. I started with having a Honda 2000i generator for charging at anchor or on the mooring. If that did not work out an inboard marine diesel generator was my Plan B. Never had to go there. Honda handles all my needs. Added a 48 volt wind turbine and solar panels and hardly use the generator except maybe on a windless day when I need to do some extended electro-sailing. I'd never go back to diesel.
 
#77 · (Edited)
SailingCinderella,

I just went through your blog. Great stuff! It raises a bunch of questions.

1. Any other considerations as to the motor purchase? Brushless vs Brushes? Why Manta?
2. How did you determine/make the motor would compatible w/ the prop shaft?
3. How did you overcome concerns about motor dependability vs the ones that are being sold for marine purposes (which seem to be ridiculously expensive)
4. Can you talk a bit about the controller? In hindsight, any other considerations other than programmability, regen-ability, reverse-ability & headroom? Looks like you selected a controller that was 3x the motor's rating.
5. I'm assuming Seattle Boat Works calculated minimum specs but I can't imagine they'd be too happy about using their services and then not purchasing their products (Clean eMarine Thoosa, etc). How did you manage this? just not tell them what your intentions were. Not judging at all. I think these companies are gouging people.
6. What was the resistor and diode for? You didn't really explain them.
7. Is there a limit to how much tonnage these motors can reasonably drive?
8. What would you do differently now that you've been through the process and have experience under your belt?
9. Any thoughts on monitoring draw & regeneration?
10. What types of problems have you experienced since installing?
11. Any thoughts on isolating the components from a lightening strike?
12. What type of programming does one do to the controller (w/ a PC)?

So many thoughts running through my head!! Thanks a bunch! EXCITING

PSea
 
#80 ·
SailingCinderella,

I just went through your blog. Great stuff! It raises a bunch of questions.

1. Any other considerations as to the motor purchase? Brushless vs Brushes? Why Manta? - I went Manta because of the price of controllers. The main options are SEPEX PM or AC. AC is theoretically the most efficient and powerful, but after running the numbers on my boat, I was able to get away with DC (considerably cheaper controller and motor). That leaves SEPEX and PM, lots of people are using SEPEX motors for EV conversions, old forklifts are usually the donor. They work, but are usually much harder to find a regen controller for, and require voltage to excite the coils, which sounds like less efficiency. I decided to go PM and saw the Manta on Ebay for cheap. The power curves on the motor seemed questionable, but at the time the motors were only $300, so I went for it. It has turned out to be great. I don't motor at max speed hardly ever (unless the bridge guys are holding open for me) and I get about 6 miles of range out of the cheapest O'Riely marine hybrid batteries they sell. If funds were unlimited I'd probably buy some Fireflys.

2. How did you determine/make the motor would compatible w/ the prop shaft? - I grew up on a farm working on old tractors and fixing old hay balers every season, I was just going to make it work. That being said, ideally you gear these motors down. Regardless of what "conversion" the diesel guys show you, we are all constrained to the propeller. They don't like to spin faster than 1500 RPM due to cavitation which proceeds to destroy the prop. Knowing that this motor will spin at 3600 RPM at full bore, I geared it down as much as I could (roughly 2.5 - 1). On my prop shaft I installed a pulley and on the motor I installed a pulley, The belt drive is super quiet and belts can handle way more HP than my little motor can make.

3. How did you overcome concerns about motor dependability vs the ones that are being sold for marine purposes (which seem to be ridiculously expensive) - Motors are very simple, one moving part, I'm not worried

4. Can you talk a bit about the controller? In hindsight, any other considerations other than programmability, regen-ability, reverse-ability & headroom? Looks like you selected a controller that was 3x the motor's rating.
I wanted overkill, the controllers are not designed to run peak loads for very long, you basically want to double what your motor would require at peak. Most controllers out there now can be programmed, so that is kind of standard. Regen is not standard, and these motor produce lots of power spinning as a generator. In regen mode, the controller has to handle a lot, probably more than actually motoring, another reason to go big there. Having an internal reverse is also nice, I just programmed my potentiometer to recognize the middle as "neutral" and I was able to eliminate complicated contactors. Price was also a factor for me, which is why I went with Kelly, they were spoken highly of. I have been happy with it, and if you are willing to wait a bit they are responsive, just halfway around the world.

5. I'm assuming Seattle Boat Works calculated minimum specs but I can't imagine they'd be too happy about using their services and then not purchasing their products (Clean eMarine Thoosa, etc). How did you manage this? just not tell them what your intentions were. Not judging at all. I think these companies are gouging people. - I ran the numbers myself, but Alex Wilkenson here in Seattle is pretty much the PNW pioneer in EV and the more boats running EV out here proving it can be done is only helpful to him. I also got a quote from the Annapolis based EV group which gave similar numbers. (Sort of triple checking my work) That is what made me do it myself in the first place, $7k without batteries!

6. What was the resistor and diode for? You didn't really explain them. - They were required for the controller. The schematic they had online had them, so I kept them when I made my modified wiring diagram. They are controller specific.

7. Is there a limit to how much tonnage these motors can reasonably drive - That is a good question and its more based on hull shape. I am not sure, but to put it into perspective my motor's max is 100amps, I use 25 at hull speed...

8. What would you do differently now that you've been through the process and have experience under your belt? - Build a more robust motor mount and make it easier to tighten and loosen the belt. What I have works, and I have no doubts will take me around the world, but my tendency is to overbuild and that didn't happen on this rushed project.

9. Any thoughts on monitoring draw & regeneration? - I use a cheap amazon monitor I got for $15 it works great, but is not waterproof, so it is in my cabin. I would consider buying the throttle assembly from electrovolt if I had more money. Theirs looks slick and my battery meter is not smart and does not give accurate voltage while motoring.

10. What types of problems have you experienced since installing? - I failed to ground my contactor in the beginning and the motor never got enough power to spin. That was frustrating, but other than that, none. the motor is great.

11. Any thoughts on isolating the components from a lightening strike? - I am not sure how I would do it, or if it would really make any difference. Living in the PNW, I hadn't though of it. I guess I would just keep sailing her, the motor at that point would probably be the last of my worries.

12. What type of programming does one do to the controller (w/ a PC)? - Most controllers connect to PC via RS232, which I am very familiar with due to work. Basically you connect it to your PC, run the program that comes with the controller and follow the steps. It's really easy, but some parts were a bit confusing. Kelly was pretty good at clarifying when I emailed them.

So many thoughts running through my head!! Thanks a bunch! EXCITING

PSea
See answers above

If I could do it again, I would not use the standard throttle lever. I would much rather a dial, clean, simple, and never tangles the sheets! I could mount the thing on my bulkhead and it would be easier to turn as well.

Glad to hear I can help someone! feel free to email me if you have any questions. I am not a frequenter of this forum. sailingcinderella@gmail.com

Cheers!
 
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