Finaly starting my Electric Kayak project.

[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

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....

You just need enough power to get up on a plane and you're fine. You definately would count as a light displacement boat. lol


"A light displacement boat such as a dinghy, a ULDB, or a multihull doesn't have so much water to move out of the way - so they make smaller waves. When they reach the speed that would be hull speed for a heavy boat the wave system is not big enough to trap them. They are able to exceed the "speed limit" where bow and stern waves coincide. A planing hull actually climbs up its own bow wave and is lifted partially out of the water. "

 

[Lock]

Kinda doubt that the standard (human-powered) kayak hulls are designed for planing... eg semi-circular hull shape with flat run aft...
tks
Lock

 

[Hyena]

Yeah I think it'd be extreme difficult to get a kayak up on the plane!
Mind you, post a video of one with the front half hanging out of the water while motoring along and I'll be hugely impressed

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.

That's not too shabby for 12v and 15a. Bump it up to 24v and that'd probably be about as fast as a kayak hull could go anyway. Again, I'm happy to be proven wrong if someone can post a video of a motorised kayak overtaking waterskiiers :lol:

 

[liveforphysics]

[youtube]lbDT0yotbPg[/youtube]

Look like it comes up on a plane nicely to me. That's just a tiny little outboard for power. I'm sure with a little battery weight in the front you could make it behave at a better angle.
[youtube]FQyG0LGB6Og&NR[/youtube]

 

[Hyena]

haha
My kayak is the same model as this so it'd be very difficult to get that sort of action happening.

 

[liveforphysics]

haha
My kayak is the same model as this so it'd be very difficult to get that sort of action happening.

Hmm... I bet it would take some grunt to get that up on a plane, but I'm sure it would get there with the right amount of power.


In vehicle top-speed record breaking, there are weird aerodynamic stages the cars go through as they work towards higher and higher speeds. I remember something about the toyota MR2 requiring less torque at the wheels to maintain 180mph than 165mph, because something was going entirely wrong with the wake of the car at 165mph, it took huge power to push past that point, but then it gained speed easily for a period before having the normal speed increasing at the square of power relationship start happening again. I think similar things happen to boats as they go up on a plane, but I'm definitely not any sort of boat expert. lol

No matter the speed, playing out in a boat all looks like a good time to me.

 

[Kurt]

In the past, I would have done all I could to make this thing crazy fast. Building the kayak into a over powered full throttle drag boat. But after years of driving and racing highly modified Honda's. I Just had to give that part of my life up before I hurt myself or some one. Though when sifting around in the garage for stainless steel to make the trolling motor bracket . I did come across my old Yamaha R1 quad carbed b16a head. Just for a second I started to have silly idea's about an ice motor on the kayak. But I have learnt to ignore this kinda thinking now :lol:

quick Video from the weekend test trip.
http://www.youtube.com/watch?v=2yQArqtfKVw

After charging the 60ah sla battery today. It took 24ah to charge it but like others have said its not the best indication of how much capacity was used. But at least I know actual ah used is less than 24a. I can go out on the lake for a couple of hrs no problem with the 60ah sla. The battery was showing 12.35v when I got them home after the trip. I know a displacement hull like my kayak will probably max out at around 12kmh before you would have to really start winding on the power to overcome its hull design. I will try running this motor at 24v and if I can get 10kmh on the water from it that's all I would ever need from a fishing kayak.

It was a funny Trip all up we got out on the water fine and headed straight across the lake to drop our freshwater lobster trap off in a little sheltered section. About 1/2 way across the lake I soon realised that I should have put the bungs into the scupper holes on the kayak. With the weight of the battery the kayak wasn't sitting dead flat and they were probably letting more water in than self draining out. So rather than draining out the water was collecting under my seat This cool lake water and the 600ml iced coffee I had just drank before going out. Made me want to pee bad! So it was a race to the other side like a medical emergency :lol:. When we did make it there I found there was thick weed on the edge of the lake that soon became tangled in the prop. I resorted to the paddles in desperation ploughing through the weed beaching the kayak and jumping over my wife and daughter like a crazy man.

Back on board and feeling much better. It was time to get out of the weed and bait up the trap. Looking under the hatch I couldn't see my bait container. It had slid to the very back of our kayak out of reach So back through the weeds we had to go. So I could get on land and lift the back of the kayak up so the container slid forward and we could reach it. Now we had set the trap and everything was looking good. Of we went under power to get some fishing done. I came up to a nice snag y section and past my wife her a rod and began casting mine . I only to realise my wife had no idea how to cast a fishing rod and almost took my eye out and hooking my shirt. She even managed to get her line caught in the prop After 10 years of marriage. I forgot I hadn't taken her fishing before.

We went on with just me fishing a little more. Until we got some very nasty black clouds rolling in and the humidity was realy building up for a big summer storm. lots of lightning and it was getting kinda dark and nasty. Then the rain came down and very heavy as well. So we motored back the couple of km to pull up our trap. My wife pulled it up to find some really big and healthy red claws in there. Great at least we got something. They were to big to fit into the plastic container we had. So they stayed in the trap for the ride back to the car. I past the trap to my wife and she held it by the string only to find the not slip away and we both watched the trap slip off the side of the kayak . The trap and the red claws. Sank to the bottom of the lake behind us :x This was not our day.

Kurt

 

[liveforphysics]

Lol! What a fun trip!

Almost makes me wana do a powered canoe

But much more amazing is that you also have a B16A head with R1 carbs fitted to it! some guy pointed that out laying on a bucket in the background of my broaching video just a few weeks ago! I didn't imagine there would be another person on this board with the same very rare setup. I also retired my much loved B-series after I had the chance to tinker with the K-series a bit, and just hopelessly fell head over heals in love.


Great job on your boat project, and its great to have another Honda fan on the board.

Best Wishes,
-Luke

 

[Jeremy Harris]

.....before having the normal speed increasing at the square of power relationship......

Errr..... Aerodynamic drag goes up in proportion to the square of air speed, but power required to overcome it goes up in proportion to the cube of airspeed. Laws of physics and all that..........

Jeremy

(aero drag = 1/2 x Rho x Cd x A x V² and aero power = aero drag x V, so power to overcome aero drag = 1/2 x Rho x Cd x A x V³)

 

[liveforphysics]

Thank you for catching my mistake Jeremy.

You are of course right

 

[Jeremy Harris]

Sorry, Luke, I wouldn't normally play the pedant on here, but with a username like yours I just couldn't resist!

As a well known Scots engineer would say "Ye cannae change the laws of physics, capt'n" (often followed by "she cannae take much more o' this".......).

Jeremy (died in the wool Trekkie..............)

 

[Kurt]

The b16a didn't last long before I spun a bearing. More my fult as I neglected that engine a bit. Ended up going real old school. Took the original 1500cc 1984 ew block bored it out and fitted some high comp pistons I think they were for a Suzuki Vitara. Spent a lot of time balancing and getting everything spot on. I then grafted a twin cam zc head to the ew block with a ton of head work. Built a SS manifold for the R1 carbs to fit that head. I also ran a Suzuki GXR exhaust at the rear.The remainder of the system was hand made . This was actually my favourite set-up. It was good for about 200hp and made a great everyday car. That little 3rd gen civic on a diet was only 700kg. Good for flat 13sec 1/4.Not really a drag car more fun on the twisty country roads at full tilt 9000rpm through them crabs I could listen to that all day very addictive. I really liked how the old Honda everything has to be hand made as there is no real after market support for them any more. Well not in Australia anyhow.

Just a shame they are not RWD. although I did start putting my engine in the rear of another civic to be mid mount rwd but ended up having to many issues making it legal for the street and caned that project.

If I ever build a full electric car I will go find another 3rd gen civic they are so light and simple to work on. I think they would make a great platform for electric.
My 84 every day car before i sold it and started a family.

 

[Kurt]

This is a picture of the two motors. The tiny one is the 15amp 180w. It has 18lb thrust and is only 4lb total weight.Thats the one I used in the video.

The much larger one is the cheap ebay 40lb thrust motor. This one weighs 15lb and is rated at around 450w. The larger one has been boxed up and sent back as there was a problem with it.

kurt.

 

[def215]

thats some wicked hybrid motor you got there kurt(sort of like an old school LS-vtec type motor?). was the ew block originally the 1.3l or was it the 1.5l from the SI before you bored it out for vitara pistons? the quad carbs from the r1 is just friggin sick. that gsxr exhaust probably sounded badass also.

 

[Hyena]

Cool, so you mounted it off the side like that. Did you find it affected the tracking much ? Like if you gave it full throttle would it just go in that direction and keep going straight or did you have to 'feather' the steering a bit ?

Having one of those each side would be cool - good for stability and twice (well, twice-ish, given the above mentioned laws of physics ) the propulsion.

Have you got an ebay link to these motors ?

Sounds like you had a bit of bad luck on the weekend! Better luck next time!!

 

[Kurt]

With my kayak being so wide and low stability isn't a problem. The motor is only 2kg. I didn't have any trouble with the kayak tracking straight with the motor on the side.The motor bracket is just something quick that I knocked up. I plan on making a better mount that has the motor in the centre at the back. I am thinking some foot pedal steering kits for a rear kayak rudder could be used to turn the motor left and right. Then I just need to connect a brushed controller and thumb throttle.

One thing I did notice with the trolling motors when on the water you tend to draw your max amps a lot more than say an e bike on land. If I was to use a brushed motor controller. I would need one with a good solid constant amp rating. A e kayak is an entirely different beast to a e bike. I think in general throttle modulation isn't as important with a low powered kayak . I was happy with the simple 2 speed switch and reverse. Making everything hands free is what I would like as I am trying to fish at the same time.

If your looking for a trolling motor from eBay. Its best to just type electric trolling motor in search for your local ebay. Like I said before my little motor wasn't from eBay . I just got it from a local boating and tackle shop.

i am keen to try 24v just for a short while to see what the difference is. I would also like to put a wattsup meter on it to get some data. I couldn't use my CA as they don't work on 12v.

 

[Jeremy Harris]

One thing that might well be worth trying, Kurt, is to make a new prop for the trolling motor. Rick Willoughby has a neat design that's fairly easy to fabricate, yet gives a useful efficiency improvement. His designs are optimised for human powered boats, but it's easy enough to calculate blade dimensions and pitch for any other power source.

Here's a link to some pictures of his boats and propellers: http://www.rickwill.bigpondhosting.com

Better still, take a look at Denny's trolling motor prop experiments on this thread on BoatDesign: http://www.boatdesign.net/forums/boat-design/efficient-electric-boat-27996-15.html

If you look through that thread you will find some useful stuff on props, buried amongst otherstuff. I really need to update it with current progress on the electronic stuff, but somehow haven't had the time.

Jeremy

PS: A chap opposite my house has a Toyota Celica with an exhaust a bit like the one in that pic, except instead of a silencer (muffler) he's just turned the open pipe so that it exits sideways, just in front of the front wheel, through a hole in the front air dam. To say it's freakin' loud would be the understatement of the century, I've no idea how his managed to avoid getting a ticket.

 

[Hyena]

One thing I did notice with the trolling motors when on the water you tend to draw your max amps a lot more than say an e bike on land.

Makes sense - how much harder is it to run though knee deep water than along a foot path!

I was happy with the simple 2 speed switch and reverse

Yeah that'd do me too, if you can get it doing ~10km/hr on 24v I reckon that'd be a winner. Have you opened it up yet, or know what's it doing internally for the 2 speed switch ? Would you actually need a brushed controller ? As you said you don't really need the throttle control you do on a bike. If you can't just hook it up to 24v what about if you left the 2 speeds as is for going slow and when you want to get some pace up have a 2nd 12v battery that you could switch into series and run it direct to the motor?

If your looking for a trolling motor from eBay. Its best to just type electric trolling motor in search for your local ebay. Like I said before my little motor wasn't from eBay . I just got it from a local boating and tackle shop.

Yeah I had a look on ebay but most seem to be the 40lb unit upwards which looks alot bigger than yours. What brand is yours ? I'll keep my eye out around the local boat shops

 

[Kurt]

Defiantly a good point about the prop.I think these trolling motors are a bit like a tug boat they don't go that fast but they have a lot of torque. I wouldn't be surprised if I could tow another kayak behind me without any change in top speed.If 24v doesn't do the trick I will defiantly look at props.

The two speeds on the little motor are achieved by passing the current through a resistive coil to drop the voltage.Not Very good as you draw the same amps at low speed as you to at full speed. I wouldn't run 24v through the coil - low speed as it might burn it out. I would bypass it and wire directly to high. I haven't opened the little motor up but I don't think the connections to the switches are very good as I could feel that area getting a little hot. So lots of resistance. Probably just crappy push on terminals.

The motors name is a Jarvis walker water snake 18lb salt water.I think Minnkota do a 28lb thrust motor but its still about the same size and weight as there 40lbs.

That GSXR exhaust wasn't loud.It just sounded like a nice 1000cc street bike with factory exhaust. I actually hand built a centre muffler for it to make the sound even more street able. When I took the car to the track I had a small side pipe that I could bolt directly to my centre muffler .That would exit the side of the car just behind my door. It looked great at the night time drags. Looking in the review mirror to see a foot long flame shooting from the side of the car.

 

[Hyena]

The motors name is a Jarvis walker water snake 18lb salt water

Was that $100 you paid new or 2nd hand ? If new what was the name of the place you got it ?
I've had a quick look around and so far I haven't seen one under $150. Theres a freshwater model thats $20 odd cheaper, but I need the saltwater one anyway.

 

[grindz145]

Defiantly a good point about the prop.I think these trolling motors are a bit like a tug boat they don't go that fast but they have a lot of torque. I wouldn't be surprised if I could tow another kayak behind me without any change in top speed.If 24v doesn't do the trick I will defiantly look at props.

The two speeds on the little motor are achieved by passing the current through a resistive coil to drop the voltage.Not Very good as you draw the same amps at low speed as you to at full speed. I wouldn't run 24v through the coil - low speed as it might burn it out. I would bypass it and wire directly to high. I haven't opened the little motor up but I don't think the connections to the switches are very good as I could feel that area getting a little hot. So lots of resistance. Probably just crappy push on terminals.

The motors name is a Jarvis walker water snake 18lb salt water.I think Minnkota do a 28lb thrust motor but its still about the same size and weight as there 40lbs.

That GSXR exhaust wasn't loud.It just sounded like a nice 1000cc street bike with factory exhaust. I actually hand built a centre muffler for it to make the sound even more street able. When I took the car to the track I had a small side pipe that I could bolt directly to my centre muffler .That would exit the side of the car just behind my door. It looked great at the night time drags. Looking in the review mirror to see a foot long flame shooting from the side of the car.

Hah! thats so awesome! Of course you could have just done that on a motorcycle to begin with and had a much better time (cars don't do anything for me). The 1.3 liter in my bike will easily still smoke the 1.5 liter in this car... of corse if you need a car seat or kayak rack or anything...though I've never had any trouble with my bicycle

 

[vanilla ice]

..cars don't do anything for me

I dunno man, its a lot easier to break em loose on 4 than 2. I've gotten it slideways with a hardcore sportbiker in the passenger seat and he was having a blast. For sure horse for horse, Accel is worse with a car, but there are things besides acceleration to enjoy with cars. Specially with one like the above.. its built to push you sideways not back!

BTW a dual cam zc head on an ew?

 

[Kurt]

The 18lb watersnake was on sale at rays outdoors for $119. Look it up online. I just went into BCF and they matched the price and beat it my 10%.

In Australia our 1984 honda EW 1500's are the same as the Canadian models ew2 no ccv crap. Its the same as the si 1500cc ew but no efi just a very simple down draft carby with only 2 vac hoses. If you lay out a d16a3-d16a1 1600cc head gasket over the 1500cc ew2 block you will see its all most a perfect fit. you just need to drill and tap one bolt hole a little deeper to use the longer zc head bold in that one location. The oil return ports need a little work with a dia grinder and the head will bolt on.

You need to modify the cam belt retention roller as the deck hight is a little different nothing to hard. You might wonder why you would want to go to all the trouble. The ew bottom ends have a lot of advantages.

Indestructible. I have never seen one let go. I spun mine to over 10,000rpm at times and 9000rpm every day . I even pulled it down after a couple of years of abuse . I had a friend with me at the time who was with me when I first built the engine . He was shaking his head when we pulled it down and everything measured up spot on after all that abuse. The japs in the min 80's were a bunch of crazy bastards with an obsession for perfection.It was like they were trying to prove something back then with the honda motors. I just don't see this kind of commitment any more.

Weight. was another thing You can use the stock gearbox and running gear.

I could also keep the stock engine number for my cars motor.

And last but not least I just like something different.

Economy if driven normally was 5.8L 100km on the open road at 100kmh and around 8 L 100 in the city.I even had a bet with a friend that I could balance a 50c coin on the cam cover at idle without it falling off. it didn't let me down That little motor was the perfect package.

The only problem I had with that car was it was power and sound was addictive. I found myself taking to many risks driving way to fast on the street.So before I hurt myself of some one I had to give it up.

I have a lot of friends who are into bikes and sure they have a HUGE!! power to weight advantage but on a twisty country road most of them were about the same speed as they would over take you on the straight sections and you would be on there backs in the corners.To very different beasts. So you cant really compare the two. All I can say about bikes is the ICE development in bikes is like F1 technology of a few years ago. Its as good as it gets.

Kurt.

 

[vanilla ice]

I meant the more to bow down to you than question why you did it.. I had no idea it was possible! Mad props to you my friend. No explanations needed on the reasoning.

I've been in the canyons trying to keep up with my friend's bikes (after talking smack). In the sweepers there is no chance, even with track suspension and track tires to try to match the sportbike compounds and suspension. Like you say, 450 pound bikes with 150hp.. with rider weight factored in that is 4 pounds per horse. No chance at all against skilled local riders.. my 2000 pound car would need to more than triple its power to match! One of the many times I've had to eat my crow. Like you said, the really tight stuff where they can't get on the throttle is the only place I could stay with them.

 

[Hyena]

The 18lb watersnake was on sale at rays outdoors for $119. Look it up online. I just went into BCF and they matched the price and beat it my 10%

Cool, I might try the same!