Finaly starting my Electric Kayak project.

[Kurt]

I have talk about building an electric motor driven kayak some time ago. Finally I have got around to starting this project. Starting with the purchase of a new double sit on top fishing kayak.I also now have a 40lb thrust 12v trolling motor.I have a large plastic 12v automotive battery box.At this stage I have gathered together 4 of my old sla ebike bricks that haven't been getting any use. They have been on float charge and should be in reasonable condition for initial testing. All 4 battery's give me 58ah at 12v.

The trolling motor is rated at 408w at 12v. So it will pull about 34 amps.I have only had the motor for about 20 min and after connecting it to a battery and testing all 5 forward speeds and 3 reverse to make sure it works. I started pulling it apart.

Why?.....Looking at how this motor regulates its speeds I think its going to be very inefficient.Inside the large motor housing is a series of coils and by directing the power through these resistive coils they are able to regulate the speed. The bad thing about this design is weather your running at speed 1 or speed 5 the little brushed motor will draw the same amps from the battery 34amps!!! The motor is a little over kill for my kayak so I want to run it at speed 1 or 2 most of the time. But what's the point if its going to draw the same amps as full speed.

So my plan is to bypass the speed coil and use electronic speed control for infinite speed control and better efficiency. When opening the plastic box at the top of the unit I found a simple multi position HD switch. The switch had two power in leads that connect to the battery. Then there is 4 wires running from the switch down the shaft top the motor. Two thick 10g wires and two 18g wires. I am assuming the two 10g wires would go directly to the motor for max speed. connecting a battery to them seems to confirm this. Using the other two 18g wires as + gives me two slower speeds.

But that's only 3 speeds from the 4 wires how do they get the other two speeds for a total of 5 ?

Anyhow that's not to important at this stage but still nice to know. What I plan to do is connect a cheap brushed speed controller to the 10g wires. I was thinking of something like a Ecrazyman 24v controller something with a 30 or 35a limit. The problem I see with this is that it would have a LVC set at 19v or so being a 24v controller.I'm sure I could bypass this LVC or get rid of it some how? So it would be a 800w 24v controller but at 12v it would give me my 400w I want.

Or perhaps just go with something like this I looks like its electronic and got to be more efficient then the resistive coils.
http://cgi.ebay.com.au/12V-30A-DC-M...cessories_Remote_Controls?hash=item2a00879748

That's my plan to start with as it seems simple cheap and easy.

I was also wondering how the motor would handle 24v or 36v. As long as I didn't go over the 408w say 36v with a 10 or 12a controller? Then I could use my headway lithium packs two of them for 36v 40ah

Any ideas or thoughts on the project or better suggestions to my plans would be great.

Kurt.

 

[grindz145]

This looks like a great project! I'm pretty surprised that they would use a rheostat type speed regulator for battery power... I imagine this would own at full throttle though Maybe ill try something like this next summer for cruising around the Erie canal. I could tow it there with my e-bike

 

[Kurt]

I just had another idea what about a brushed RC spead controller?

I lust had a quick look on google and can see that the brushed rc speed controllers are very cheap. I was thinking of one designed for rc boats as some are sealed in epoxy so waterproof . It doesn't look to hard to find one they can handle 30a cont. I presume I could use a servo tester as throttle? Hey I could go all out and make my Kayak completely RC LOL . Then I can sit on the bank and troll for fish .

Seriously what do you guys think of a brushed rc motor controller?

This one is only $30 Au delivered. clams its good for 40a cont . 4-10 cells voltage of 4.8-12v.
10 cells is for 1.2v cells or 12v. A fully charged sla pack would be 13v But more like 12.5 or 12 under load. I guess this would be ok?
If something like this is good where can I get a servo tester with pot to control speed?
I found this little one from e sky for $10. I think the esp will power it to.But what about reverse?

So many questions :?

For now I will start working on the things I am skilled at .Welding up my stainless steel mounting bracket, battery bracket and turning linkages tomorrow.Should only be a day job. Hopefully in the mean time some one with more knowledge on the electronic-RC side can sort out some of my questions.

 

[grindz145]

The Brushed RC controller should work fine except I am a little weary of the voltage. You essentially need anything that will PWM the output at the 14V ~40A Max. As far as reverse goes you can use the same speed controller and just reverse the polarity (like with some type of mechanical switch) I imagine there is already a switch for this purpose somwhere in the trolling motor which you could tap into.

You could also use something like this http://cgi.ebay.com/50amp-ESC-Electronic-Speed-Controller-for-Brushed-Motor_W0QQitemZ320457810944QQcmdZViewItemQQptZRadio_Control_Parts_Accessories?hash=item4a9cc62400#ht_500wt_1182 and mod it so there is no low voltage cutoff (assuming there is one) you could wire it up to the potentiometer on the existing controls too! Something like that will work and it shouldn't be all that expensive, it looks like the RC controllers will treat you well. I would however go overkill on the controller because of the inrush current of the larger motor, I imagine it is substantially more than on an RC vehicle, but then again maybe I'm not thinking the right scale....

great freakin project.

 

[gilnet]

would a foot pedal work?They have them for trolling motors.I also have them for dremel and various tools.

 

[Kurt]

Yes I have seen the foot pedals. They just look a little bulky for a kayak and I think they are just a simple throttle with large plastic housing.

Most of the electric trolling motor manufactures sell two kinds of motors the simple resistive coil and the more expesive what they call MAXIMISER :lol: technology units . The maximiser units just have a simple brushed electronic speed controller. They cost an extra couple of hundred $ more. That's marketing to the ignorant for you

So the plan is just to buy a $30 brushed controller and save $200.

There has been a setback with my ebay trolling motor. I was doing some more testing with the prop in a large tub of water. The motor gave off a horrible noise and jammed solid. I removed the end plate from the motor as it just took two bolts and it was off. It was bad news for this motor. One of the winding strands was so loose that it had jammed between the motor shaft and the magnets. The windings in general were all very loose. I put it all back together and boxed it up.So I am requesting a refund on that motor.

So now I need a new trolling motor and I will give ebay a miss this time Looking at the size of my broken 40lb thrust motor this time I might go for something smaller like the mini koda 28lb. See how I go. One good thing is the mounting brackets for the trolling motors a very universal. So I can carry on with my 1/2 complete motor mount.

After doing some research online I found what I was looking for http://www.cfnet.net/tm/ This guy has done all the hard work and testing for me and its a good read.

Kurt.

 

[gestalt]

When I was a kid me and my dad built a raft out of decking material and marine styrofoam. We slapped a trolling motor and a deep cyle truck battery on it and it scooted around the lake quite well. I immagine that on a kyak it's going to scream. I hope you find a way to use your lithium batteries with this, seems like sla's would be a bit heavy for that boats balance.

 

[grindz145]

Yes I have seen the foot pedals. They just look a little bulky for a kayak and I think they are just a simple throttle with large plastic housing.

Most of the electric trolling motor manufactures sell two kinds of motors the simple resistive coil and the more expesive what they call MAXIMISER :lol: technology units . The maximiser units just have a simple brushed electronic speed controller. They cost an extra couple of hundred $ more. That's marketing to the ignorant for you

So the plan is just to buy a $30 brushed controller and save $200.

There has been a setback with my ebay trolling motor. I was doing some more testing with the prop in a large tub of water. The motor gave off a horrible noise and jammed solid. I removed the end plate from the motor as it just took two bolts and it was off. It was bad news for this motor. One of the winding strands was so loose that it had jammed between the motor shaft and the magnets. The windings in general were all very loose. I put it all back together and boxed it up.So I am requesting a refund on that motor.

So now I need a new trolling motor and I will give ebay a miss this time Looking at the size of my broken 40lb thrust motor this time I might go for something smaller like the mini koda 28lb. See how I go. One good thing is the mounting brackets for the trolling motors a very universal. So I can carry on with my 1/2 complete motor mount.

After doing some research online I found what I was looking for http://www.cfnet.net/tm/ This guy has done all the hard work and testing for me and its a good read.

Kurt.

hah! It's all been done before Motherload. This is so cool I have to do this next summer. (o yeah it is summer there isn't it, lucky!

 

[Hyena]

Hey Kurt,
I was thinking just last week about ways I could make my kayak electric. I was thinking about making some sort of paddle steamer type mod to an old hub motor but I guess modifying a trolling motor works too... :lol:

Check out oatley electronics for cheap brushed controllers. I'm not sure how the price compares with buying from china but atleast they're local.

Something like this would probably be good
http://secure.oatleyelectronics.com//product_info.php?cPath=94&products_id=686&osCsid=e391a14c75f88badd3680a7afb974b53

And stop entertaining silly ideas about SLA, in a light weight craft like a kayak - 6S zippy / turnigy lipos are where it's at!

Your only problem once you've got some pace up will be keeping the thing straight. Or that might be just a limitation of my kayak - it tends to not track terribly straight when I paddle as fast as I can. If you get something with a fin or decent hull you'll probably be ok though.

 

[BMI]

If you use Li-Po in a kayak you must have a death wish. At least on a bike you can dump the bike and run if you have a battery fire. Not so easy to get away quickly when you are in a kayak.

http://video.google.fr/videosearch?q=mon+v%C3%A9lo+part&hl=fr&emb=0&aq=f#q=mon+v%C3%A9lo+part&hl=fr&emb=0&aq=f&qvid=mon+v%C3%A9lo+part&vid=-1086364983225733633

 

[gilnet]

lith and water don't mix well.

 

[BMI]

lith and water don't mix well.

Li-Poly + water = disaster!

 

[Kurt]

I have 40ah of lifpo4 at 36vfrom my ebikes.

but kayaks and ebikes are two different beasts. With e bikes weight is critical especial when you need to climb a hill .loading your bike frame up with sla isn't a practical option even finding the space for it is a problem so lithium is king. With a kayak weight isn't so important Mine has a load limit of 600lb as you don't climb hills on the water the motor load is constant . Yes the kayak will sit a little lower in the water if you load it up and there will be more drag on the hull. From experience When paddling and my wife gets into our kayak she is 50kg and I don't really notice much difference when its just me paddling. So a 60lb 100ah sla on the back isn't a big problem . On a e bike that would be a big problem.

Anyhow today I finished welding up a quick stainless steel bracket for my kayak motor. I sent the first broken ebay motor back . Friday I purchased a smaller 18lb thrust trolling motor for $100. This new tiny little motor is built for kayaks and small inflatable. It draws about 15a max or 200w and has a simple F/R toggle switch and a speed 1/2 toggle switch. The best part about it is the size and weight . Its only 2kg total and has a very short shaft. I tyred the motor out in a large bucket of water and its got some nice torque. I am predicting around 5kmh speed so about as fast as paddling but its constant and better steering and keeps my hands free for fishing. I will test with gps for speed and range tomorrow.

Tomorrow my wife, daughter and I are driving about 3hrs north of Brisbane to a freshwater lake for the day. We will be fishing from the kayak and exploring the lake for the first time. I have 60ah of sla and a smaller 20ah sla reserve for the day + 2 paddles if we need them :lol: . I am taking the digital camera and video camera so will post a trip report on how the e kayak works out. It will be a primitive trial run to take some data before I go all out and fit speed controllers and servo driven steering.

Kurt.

The lake
http://images.google.com.au/imgres...prev=/images?q=lake+borumber&hl=en&sa=N&um=1

 

[BMI]

I have 40ah of lifpo4 at 36vfrom my ebikes.

but kayaks and ebikes are two different beasts. With e bikes weight is critical especial when you need to climb a hill .loading your bike frame up with sla isn't a practical option even finding the space for it is a problem so lithium is king. With a kayak weight isn't so important Mine has a load limit of 600lb as you don't climb hills on the water the motor load is constant . Yes the kayak will sit a little lower in the water if you load it up and there will be more drag on the hull. From experience When paddling and my wife gets into our kayak she is 50kg and I don't really notice much difference when its just me paddling. So a 60lb 100ah sla on the back isn't a big problem . On a e bike that would be a big problem.

Anyhow today I finished welding up a quick stainless steel bracket for my kayak motor. I sent the first broken ebay motor back . Friday I purchased a smaller 18lb thrust trolling motor for $100. This new tiny little motor is built for kayaks and small inflatable. It draws about 15a max or 200w and has a simple F/R toggle switch and a speed 1/2 toggle switch. The best part about it is the size and weight . Its only 2kg total and has a very short shaft. I tyred the motor out in a large bucket of water and its got some nice torque. I am predicting around 5kmh speed so about as fast as paddling but its constant and better steering and keeps my hands free for fishing. I will test with gps for speed and range tomorrow.

Tomorrow my wife, daughter and I are driving about 3hrs north of Brisbane to a freshwater lake for the day. We will be fishing from the kayak and exploring the lake for the first time. I have 60ah of sla and a smaller 20ah sla reserve for the day + 2 paddles if we need them :lol: . I am taking the digital camera and video camera so will post a trip report on how the e kayak works out. It will be a primitive trial run to take some data before I go all out and fit speed controllers and servo driven steering.

Kurt.

The lake
http://images.google.com.au/imgres...prev=/images?q=lake+borumber&hl=en&sa=N&um=1

Just so happens where the lake you are going to is very close to where the Australian distributor of the world's most efficient professional electric kayak motors is based. He lives in Noosa (just a bit of useless information).

 

[Hyena]

a 60lb 100ah sla on the back isn't a big problem

Makes it a bit heavy on your shoulder though
I suppose it depends on how close you are from the water. I live about 3 minutes walk from the waters edge so I usually just carry my kayak down a bush track. Lugging extra SLAs would suck, but I guess if you're driving places and have a car nearby it'd be fine.

Next project is to cover the hull in thin, flexible solar panels to recoup some energy while fishing

As for lipos, bah! you're all sissies
They'd be fine in a good waterproof box. If they did start to go up just drop them over the side and paddle off, or go for a swim :lol:

I am taking the digital camera and video camera so will post a trip report on how the e kayak works out. It will be a primitive trial run to take some data before I go all out and fit speed controllers and servo driven steering.

cool. how are you mounting it ? Off the back or the side ? I've seen some mounted like an out rigger, and although they look a bit odd I guess they're re easy to get to and raise and lower.

 

[grindz145]

Pb is actually perfect in a boat (so long as your not racing or something) lots of current/cheap/safe.

and you can use it as an anchor just in case

 

[northernmike]

The ultimate tool for kayak fishermen—or any paddler who wants to keep moving while they take a rest—this motor installs easily to any rigid kayak. Sold as a complete package, the system includes a throttle/gear shift, “kick up” mount, ultra-quiet, efficient motor and a GPS housed with the 29.6V, 8Ah lithium-manganese battery. With a data feed from the GPS, the throttle/gear shift includes a digital display for battery state of charge, remaining range, speed and current input power. Capable of powering a kayak for up to seven hours at 2.5mph, this set-up works great for trolling or holding a position in windy conditions. It is also a great choice for ocean kayakers who want a reserve motor for safety reasons—or for family kayakers who like to paddle, but who also appreciate the convenience

* Application: For hardshell kayak installation
* Watts: Input power: 400W; Output power: >180W
* Static Thrust: 33lb.
* Battery Type: 8Ah lithium-manganese
* Battery Life: Up to 7 hours, depending on speed and conditions
* Propeller: 8"dia. x 8 pitch
* Steering: Can be static mounted (steer with kayak rudder); Can be connected to rudder cables
* Gearing: Continously variable forward/neutral/reverse
* Weight: 16lb.
...


There are larger ones, too... brushless PWM and NICELY built, in my humble opinion, having seen one in person.

 

[Hyena]

That sounds cool, although I bet it costs a small fortune! The LCD display would be great for ebikes too.
7 hrs from an 8ah battery sounds wildly optimistic though!

 

[grindz145]

That is definately as sweet as it gets, but a couple of cheap deep cycle marine batteries and a motor only cost $200 and will outlast that battery 10x over

It is a perfecct solution though!

 

[BMI]

That sounds cool, although I bet it costs a small fortune! The LCD display would be great for ebikes too.
7 hrs from an 8ah battery sounds wildly optimistic though!

You get what you pay for. If you want quality and performance it costs more....just a simple fact of life!
The running time is not "optimistic" (as you put it) it is fact.
The Torqeedo kayak motor is by far the best performing motor on the market for a kayak or canoe application.

You may not realise that the efficiency of all of your small and cheap trolling motors (such are Minn Kota for example) is barely 10% efficient compared to the efficiency of the Torqeedo kayak motor which exceeds 50%. This is measured as OVERALL efficiency DELIVERED AT THE PROP.

Therefore a very small lithium battery with this motor will give you the same motor running time and cruising distance as a cheap trolling motor powered by a ton of lead.

 

[Jeremy Harris]

I've been working on a light, efficient, electric boat for a while now and have found out quite a bit about efficiency along the way. The brushed trolling motors are all pretty poor in terms of overall efficiency, especially those with resistive speed controls. Their major problem is the high prop speed, small prop diameter and inefficient prop design (their props are optimised for reduced weed entanglement, to the detriment of efficiency).

The Torqueedo is the most efficient commercially available unit, but has a couple of features that I don't like. The first is the noise. It uses a model aircraft type outrunner brushless motor driving through a gearbox. The motor runs at high rpm and consequently the gearbox whines a fair bit. For me, this defeats one of the major benefits of electric propulsion on a boat, near-silence. The other feature I don't like about the Torqueedo is the price, it's a very expensive propulsion solution when compared to other options.

I've opted to build my own drive unit, using a direct drive brushless motor. I've rewound a big outrunner to run at a much lower rpm, at a much reduced power, whilst increasing it's torque. So far, I've got the motor efficiency, with controller, up to about 85% at cruise power.

The next area I've been working on is the prop efficiency. To optimise this I need a large diameter, narrow blade, prop, like those used on human powered boats. Although this significantly improves efficiency over a traditional high speed boat prop, it catches weed very well indeed. To get around this I'm making the blades fold, following the lead set by Rick Willoughby with his human powered boat props. If a blade catches a bit of weed, it will just fold back allowing the weed to slide off.

The aim is to get prop efficiency up to around 75% or so, which will give an overall efficiency that's comparable with the Torqueedo, but without the loud whining noise or high cost.

I'm using LiFePO4 cells, sealed into a large, sealed, ABS box, with watertight connectors. Weight is every bit as important on a low powered boat as it is on a bike, if anything more so. More weight means more wetted area (the hull sinks lower in the water) which means more drag. Virtually all of the drag at low speeds comes from viscous skin frictional losses, rather than wave making, so anything that reduces wetted area is a good thing (as long as it doesn't reduce waterline length).

Good luck with the project, Kurt, I think you're going the right way to build a useful boat using off-the-shelf stuff.

Jeremy

 

[liveforphysics]

Did anyone else find the marketing picture of the torqueedo setup cute?


29.6v 8Ah battery = 236.8Whrs.

This how much energy they are working with. Now look at the display. 4.5mph and 273w power draw on even a 100% battery = 3.9miles of range. They display a very optimistic 11.3mi. They would need to be packing at least 3 of the torqueedo batteries to make that display a reality.


Jeremy- You're so right about direct drive for a boat. Why add the complexity, failure point, and noise to a situation that can just as well be silent and more reliable?

 

[Kurt]

I was just about to post the same thing about that kit 236.8 whrs is a FACT! and that's not a lot of whr's So if you run the motor at 33.8w then it will last 7 hrs 33.8w is going to be useless. So its optimistic.

The kit looks nice and it looks quality i guess you could always use a bigger lithium battery.

A 100ah 12v sla at 50% capacity has 600whrs

I just got back from my kayaking lake trip tonight. I ran my little 180w trolling motor 15a at 12v all afternoon. Speed 1 super slow around 2kmh and only good for holding the kayak against a strong wind-current. Speed 2 was around 5-6kmh and about the same as two people paddling briskly.

I was using my old e bike sla battery's to give me 360whrs at 50% capacity.

I will do a full report tomorrow with video and data.I am charging the battery now so we will see how many AH it shows on the display that was taken out. I couldn't use my CA to collect better data as it doesn't work on 12v . I think 14v is the lowest they work on. I was on the water for around 4hrs but will have to calculate the distance.It should make for a funny story as there was some dramas over the 4hrs:lol: But I learnt a lot today.

I will fill you in tomorrow.

Kurt

 

[liveforphysics]

Remember when measuring the current you put back into a lead acid battery, they have a really crappy charging efficiency, and it varies a large amount with temperature. You often will find a charge efficiency of 60%-80, depending on temp and the health of the battery. So if you measure putting 10Ah in, in reality you may have only added 6-8Ah of capacity back to the battery. It can be easy to be mislead about how much energy you're using when trying to find out by measuring the amount put back into the battery during charging.


The boat trip sounds like fun! Also sounds like you need to step that power up about 10 notches

 

[grindz145]

Remember when measuring the current you put back into a lead acid battery, they have a really crappy charging efficiency, and it varies a large amount with temperature. You often will find a charge efficiency of 60%-80, depending on temp and the health of the battery. So if you measure putting 10Ah in, in reality you may have only added 6-8Ah of capacity back to the battery. It can be easy to be mislead about how much energy you're using when trying to find out by measuring the amount put back into the battery during charging.


The boat trip sounds like fun! Also sounds like you need to step that power up about 10 notches

The thing about stepping up the power on a kayak is it has a
maximum hull speed, so after you hit it you endup pushing a bunch
of water but with no added performance. I suppose you can do the equivalent of wicked ebike burnouts....