Workman Stretch Mover Electric Trike - power not speed

[jeff peterson]

First a little back ground... Plan: build a 3 wheel bike to carry passangers or cargo around a small flat road beach town. I bought a cheap ebay rickshaw trike. [$320 delivered] I got what I paid for. Next I bought an unknown brand 48 volt gearless 500 watt front hub motor kit and 4 SLA 20 hr batteries. I put it all together and was surprised how well it worked for the first week. After that the rickshaw kinda died one part after another and the motors spokes broke do to the lateral strain while turning. But I learned a bit and was hooked on the idea.

I have now bought a Workman 3 speed Stretch Mover Trike with HD rear rims, kevlar tires and front drum brake. This is one heavy, well built trike, with rear spokes about the diameter of my thumb! Next I added a Curry 450w 24v chain drive bike motor. Mounted the Curry motor to the frame and connected the chain to the 7/8" axel via an additional 20 tooth free wheel sprocket. The speed of the trike seems to be about 15 mph on the flats without pedaling. FYI - you can only pedal about 12mph in 3rd gear. I have the same batteries as before, but they are now set up at 24v 40hr

I had 2 thoughts. 1- connect the 450 watt motor to the 3 spd hub and connecting the pedals to the rear axel via the 20 tooth free wheel sprocket. 2- adding a second 450 watt motor to the drive system. Please understand, 15 mph is fast enough. But I want to be able to haul concrete, mulch, sand.... from the local stores, or a normal grocery run, or recycle run or two passengers. Not at the same time of course, but maybe as far as 5 miles. At this time the motor connected directly to the axel can do all this. But it's often straining during start up and when crossing the canal bridge as you would expect. Moving forward, I'm hoping to reduce some of the motor strain as this can not be good for it. Plus if the motor was in first gear I could help it more via pedaling.

Questions: Will 2 motors use a lot more power on the flats than one? Is there a best way to connect them? Will a 3 spd hub handle 450 watts? What about 900 watts? Am I asking to much from an etrike?

 

[spinningmagnets]

Is it like the bike in this pic? Does the chain power one rear wheel, or are both rear wheels on the same chain-driven axle? If yes (the common configuration) would it be reasonably easy to separate the left and right rear wheels, so one wheel can be powered by the pedals and the other is independent and able to accept a motor drive?

Are all three wheels 20" or are they 24"?

 

[jeff peterson]

I ordered the trike with a 26" front HD spoked wheel with drum brake. [Brakes are very important to me] The rear 2 wheels are 20" with super HD welded spokes. The right rear wheel is fixed to the 7'8" axle, the left rear wheels free spins.

Sorry you have the wrong picture, I bought the stretch mover. I'll try to attach pictures but I don't know how at this time... If the pictures load, they are showing: the stretch mover trike ad on line [red frame],the new trike with rear seat added and the actual new trike with motor/chain that I'm using at this time. [yellow frame]

 

[TylerDurden]

Hi JP... your pix will only work for you, until you upload them to the ES server.
This is what other visitors see:

[img]file:///C:/Documents%20and%20Settings/HOUSE%20MOM/Desktop/webphotos/images/2009_0927_124608AA.jpg[/img]

When you compose or edit, there is an Upload Attachment section below the text-entry area. Use the "Choose File" button to upload. Uploading to ES will keep the pix with the topic; which is preferable to an off-site service, which may disappear if the account gets closed.

http://endless-sphere.com/forums/viewtopic.php?f=1&t=14748&start=0

 

[jeff peterson]

thanks TD! pictures are loaded. Just a bit bigger than expected.

 

[TylerDurden]

Looking good, JP.

Two motors will draw twice the power from the batteries, if offered twice the work... it takes power to do work and any number of controllers, motors & batteries will gladly kill themselves if you give them more work than they can handle.

If your controllers are matched to the motors, they can limit current to a level that prevents motor overheating (heat comes from resistance and current); but you may be underwhelmed by lackluster speed.

A good way to ensure motor longevity is to monitor motor temperature. Typical neodymium magnets die at 80C, so prudent use of gearing and throttle to keep current and temperature within safe levels is recommended. Some systems include the feature, but even cheap indoor/outdoor thermometers can be rigged.

A geared hub should handle 1000W, if shock-loading is avoided. Of course, everything has a limit; so let common-sense be your first guide.

YMMV

 

[jeff peterson]

TD, You hit on the main point of my question concerning adding a second motor. The key point is that the work should remain the same, but that it would be divided by the 2 motors. In this case I'm using work as equaling [weight x distance / time]. I don't know if this is a real calculation or not, but it's how I think of it in my head. I also understand that resistance, both friction and electrical would play a part. But how much of a part I wonder?

So let me try to explain the math problem again: If the 400lbs trike is running at full speed of 15mph, on a flat road, using 450 watt motor, for a distance of 1 mile, it would use [just for the sake of argument] 1[x] of battery power. What would be the battery power usage if I were to add a second 450 watt motor on the same chain with out any other change? Would the answer be 2[x] battery power? In my mind, 2[x] can not possibly be correct. I grant that there is more resistance due to the second motor and the fact that two motors will never work exactly the same. [call it lack of efficiency] Would efficiency is the extra power usage? If yes - What percentage of loss should I expect? Or is my think all wrong? Has anyone done this with 2 motors? Is there any place I could read up on this kind of power loss thinking? BTW - I was also thinking of using 1 throttle, 2 controllers and 2 motors. How bad of an idea is that?

Moving forward, since you don't feel a 450 watt motor will not hurt the 3 spd hub. I think I'll give that idea a try and see what happens. I read somewhere to expect a 7% loss do to the hub gears. Sadly 3rd gear will not be used since it could make the trike go too fast for safety. Which brings up another question. Can the input chain gear of 3 spd hub be replaced with a larger gear?

 

[12p3phPMDC]

Jeff,

It appears that the three speed hub is a Shimano, therefore, it shares the "3 spline" sprockets with Sturmey Archer and SRAM.

http://www.harriscyclery.com

http://sheldonbrown.com/harris/hubs-internal.html

They have an excellent selection of 3 speed sprockets in 1/8" chain and 3/32" sizes.

Chris

 

[dumbass]

TD, You hit on the main point of my question concerning adding a second motor. The key point is that the work should remain the same, but that it would be divided by the 2 motors. In this case I'm using work as equaling [weight x distance / time]. I don't know if this is a real calculation or not, but it's how I think of it in my head. I also understand that resistance, both friction and electrical would play a part. But how much of a part I wonder?

So let me try to explain the math problem again: If the 400lbs trike is running at full speed of 15mph, on a flat road, using 450 watt motor, for a distance of 1 mile, it would use [just for the sake of argument] 1[x] of battery power. What would be the battery power usage if I were to add a second 450 watt motor on the same chain with out any other change? Would the answer be 2[x] battery power? In my mind, 2[x] can not possibly be correct. I grant that there is more resistance due to the second motor and the fact that two motors will never work exactly the same. [call it lack of efficiency] Would efficiency is the extra power usage? If yes - What percentage of loss should I expect? Or is my think all wrong? Has anyone done this with 2 motors? Is there any place I could read up on this kind of power loss thinking? BTW - I was also thinking of using 1 throttle, 2 controllers and 2 motors. How bad of an idea is that?

Moving forward, since you don't feel a 450 watt motor will not hurt the 3 spd hub. I think I'll give that idea a try and see what happens. I read somewhere to expect a 7% loss do to the hub gears. Sadly 3rd gear will not be used since it could make the trike go too fast for safety. Which brings up another question. Can the input chain gear of 3 spd hub be replaced with a larger gear?

I am currently adding a second motor to my bike (cruuie Ezip). But unlike most people who do this I am not going to run 2 motors that are fixed to the axle. In stead I am relocating both motors to the "V" of the bike and they will drive through the geared side (left). I am using a Nuvinci CVS hub. My crank chain is still on it's own and the motors are on a second sprocket added to the Nuvinci hub.

The ideal situation for you is to have the motor or motors drive through your gear system. The only way I can see you being about to do that is simular to the way Cyclone motor kits do it. Whereas, the motor is chained to the crank sprocket with a freewheel on both the crank sprocket and the motor. This would be an expensive modification and could also be a major PITA to accomplish. The second best is of course as you say just add a second motor. 2 motors will run almost exactly as efficiently as one provided the load is the same. But of course as you increase the load you increase the current draw.

The Cruuie motors are brushed motors so they are easy to work with. With these motors you have 3 control/throttle options; 1...use 2 24v controllers and throttles and find a way to mechanically link the throttles together. Not a great idea and not easy, 2...use 2 controlers and share the hall voltage from one throttle with both controllers. This is the direction I am going to try but as I haven't done it yet I can't tell you how well it works. But it should be simple and straight forward., 3...Because you are running only 24v and you have 4 12v packs you could simply go 48v x 20ah. In this situation you install a single 48v controller with a matching throttle. You wire the motors in parallel. In this way each motor is sharing the voltage simular to the way Christmas tree lights work. It's a simple fool proof way to do it and it works very well. There have been a lot of postings on doing this with the Currie motors and it has reduced the heat and improved 2 motor efficiency.

 

[TylerDurden]

In addition to the above, I suggest much better brakes.

Two passengers or 500lb of 'crete is a lot of mass to stop.

 

[jeff peterson]

TD: I agree 100%, I was looking for a way to attach a disc rotor to the 7/8" shaft. but can't find one. can it connect to the Shimano 3spd?

Chris: It appears that the input chain gear can be replaced. Though I still don't know how, but guessing it and easy thing to do once I pick the number of teeth. I'd love to get my hands on an assembly manual.

Da: I saw the Nevinci hub on Staton's website. I like it, but not sure if it would fit in place of the Shimano 3spd? I'd need to know more before spending $. Your statement "2 motors will run almost exactly as efficiently as one provided the load is the same." is what I wanted to here! If I go for the second motor, I'm planning to do the 1 throttle to 2 controllers idea [your #2 idea] seems the easy route and not too pricey. It's a shame the Currie 450 watt motor does not free spin. Just incase one motor were to fail. As for connecting the crank sprocket to the 7/8" axle, It's not a problem. I'll move the motor to the Shimano 3spd [lose of the coaster brake]. Staton carried the parts I need to add a second 20 tooth free wheel sprocket which will connect to the crank [a simple bolt on job]. All I need do is slide the gears to the correct location on the axle, move chains around and fit to length. By my figures 1st should do 10mph, 2nd 15mph and 3rd 20mph. I believe 20mph is too fast for this Trike, but I'll give it a try before changing the input gear. Who knows, I may not need a second motor as I still plan to pedal...

Another question: Can you claim a electric bike as some kind of EV on your taxes? As the cost of this project increases, I love to get a few bucks back....

 

[12p3phPMDC]

Jeff,

there is a spring clip that holds the sprocket on. You just have to take that clip off.
You'll need to remove the hub to take the whole thing off of course.

How many teeth are on the sprocket you have?

I'm guessing ~23 or so from what I could tell from the pic. The largest sprocket off the shelf without adapters is 23 I think.

You may get a little more reduction, but not much it seems.

You can use a 3 speed sprocket with holes in it as an adapter to a larger sprocket, like a BMX crank sprocket, but
this will require you to bore the center of the BMX crank sprocket large enough to clear the input driver of the 3 speed
and transfer the bolt pattern, etc..

 

[diver]

I use the worksman 26 inch wheels on my trikes . one trike has over 5 k on it loaded to 500lbs plus. never had a wheel problem from worksman wheels. the new trike I'm building now will have the front hub power plus a little power assist that is geared super low for start ups on curbs and such mounted to rear drive to worksman wheels. I run Hyd disc brakes off 4 wheelers.. I like worksman parts..

TD: I agree 100%, I was looking for a way to attach a disc rotor to the 7/8" shaft. but can't find one

I go to tractor supply and by the shaft size colar and weld it to the bike freewheel adapter and use a gokart 8 in rotor for my rear brakes
http://www.tractorsupply.com/agriculture-farming-ranching/hubs-sprockets-chains/hubs/x-series-hub-7-8-in-bore-1170646

 

[dumbass]

TD: I agree 100%, I was looking for a way to attach a disc rotor to the 7/8" shaft. but can't find one. can it connect to the Shimano 3spd?

Chris: It appears that the input chain gear can be replaced. Though I still don't know how, but guessing it and easy thing to do once I pick the number of teeth. I'd love to get my hands on an assembly manual.

Da: I saw the Nevinci hub on Staton's website. I like it, but not sure if it would fit in place of the Shimano 3spd? I'd need to know more before spending $. Your statement "2 motors will run almost exactly as efficiently as one provided the load is the same." is what I wanted to here! If I go for the second motor, I'm planning to do the 1 throttle to 2 controllers idea [your #2 idea] seems the easy route and not too pricey. It's a shame the Currie 450 watt motor does not free spin. Just incase one motor were to fail. As for connecting the crank sprocket to the 7/8" axle, It's not a problem. I'll move the motor to the Shimano 3spd [lose of the coaster brake]. Staton carried the parts I need to add a second 20 tooth free wheel sprocket which will connect to the crank [a simple bolt on job]. All I need do is slide the gears to the correct location on the axle, move chains around and fit to length. By my figures 1st should do 10mph, 2nd 15mph and 3rd 20mph. I believe 20mph is too fast for this Trike, but I'll give it a try before changing the input gear. Who knows, I may not need a second motor as I still plan to pedal...

Another question: Can you claim a electric bike as some kind of EV on your taxes? As the cost of this project increases, I love to get a few bucks back....

Well this maybe your lucky day.. As I think I mentioned I am working on installing 2 450w Currie motors on my bike as we speak but it's a side job for me because of the weather. therefore, I won't complete it for a few months. However, I will eventually give a shot at installing freewheels on the motor. I have alredy looked into it and it's doable. FYI, freewheels come in 2 different bore/thread sizes that can be used. The large (standard) is the easiest but a little more heavy and the smallest gear available for it is 16t. For some this is to large. The other (smaller) freewheel has a 30mm bore and is lighter but while this is good it requires the gear to be more overhung on the motor shaft. Now a big problem just something I don't like. The nice thing about these freewheels is you can use a 13t, 14t, and 15t gears.

If you want to talk more about this send me an IM. As I said eventually I will be doing tests and maybe we can both do a test on them.

As for the Nuvinci you reall need to think that one through. The spoke size is very limited and you mentioned that you have heavy duty spokes. You would need to contact Nuvinci (great people to work with) and ask them about the spokes sizing.

I have heard that in some states Ebikes are a deduction but not in Illinois.

 

[jeff peterson]

Sorry for the delay, I seem to have a few too many projects running right now.

Da: I'd need the freewheel to be 9 tooth to match the existing sprocket. the rear spokes are the dia of my thumb... I could not lace in a Nuvinci hub and even the Staton version may not fit.

Diver: I went to the site you gave me, but Staton offered the same thing. but they also offered an "Adaptor for freewheel 7/8" ID x 1-3/8-24 OD x 1/2" wide" it can also be used to thread on a brake rotor. I think I'll go that direction.

12p3PMDC: Thanks for the info. the input and output sprocket Both have 20 teeth at this time. changing the input to 23 should make 3rd gear max at about 17mph. That's fine for me! and give me a useful 3 spd for the best of all worlds.

I've attached a PDF of my chain drive problem. the frame is too close to the chain's required running area. but I just realized if I were to change to the 23 tooth sprocket I'd have more clearance. thus the problem may no longer exist. looks like it's time to make a new motor mounting bracket and connect the motor to the 3 spd.

Thanks for all your thoughts, I'll update this post in a few weeks.

 

[dumbass]

Sorry for the delay, I seem to have a few too many projects running right now.

Da: I'd need the freewheel to be 9 tooth to match the existing sprocket. the rear spokes are the dia of my thumb... I could not lace in a Nuvinci hub and even the Staton version may not fit.

Diver: I went to the site you gave me, but Staton offered the same thing. but they also offered an "Adaptor for freewheel 7/8" ID x 1-3/8-24 OD x 1/2" wide" it can also be used to thread on a brake rotor. I think I'll go that direction.

12p3PMDC: Thanks for the info. the input and output sprocket Both have 20 teeth at this time. changing the input to 23 should make 3rd gear max at about 17mph. That's fine for me! and give me a useful 3 spd for the best of all worlds.

I've attached a PDF of my chain drive problem. the frame is too close to the chain's required running area. but I just realized if I were to change to the 23 tooth sprocket I'd have more clearance. thus the problem may no longer exist. looks like it's time to make a new motor mounting bracket and connect the motor to the 3 spd.

Thanks for all your thoughts, I'll update this post in a few weeks.

I have the Staton freewheel adapters (very nicely made). Actually I have them in both 1" and 5/8" for a project I am working on. But these are all for 16t + freewheels. The smallest freewheel made is 13t and it requires a 30mm x 1 adapter. Staton does make a 30mm x 1 adapter but not in the bore size that is needed for the Currie type motor/gearbox. I sent Staton a drawing and requested a quote. This is their response;

As for the adaptors we looked at them but the numbers do not make them worth while to even make. We would loose money on them too.

When we make another large run of the 300 parts, that is the time that we could make about 10 special parts and they cost would be 1.5 times more them the standard part or about $23.50 each. If we had a order for 25 it would drop to $18.95 each.

I have a milling maching and lathe in my basement so i may try making a few of these to see how it works out. The problem you have is the smallest freewheel that is made is 13t. And they are generally more expensive then the common ones (16t and up). 13t,14t and 15t use the small adapters and from 16t up use the standard adapters.

So why can't you change the shaft sprocket size to allow you to use a 13t or 14t freewheel?

 

[12p3phPMDC]

12p3PMDC: Thanks for the info. the input and output sprocket Both have 20 teeth at this time. changing the input to 23 should make 3rd gear max at about 17mph. That's fine for me! and give me a useful 3 spd for the best of all worlds.

No problem, glad you have a little room to change the gearing.

 

[jeff peterson]

Da:

So why can't you change the shaft sprocket size to allow you to use a 13t or 14t freewheel?

I'm guessing my wording was not the greatest. I was wanting to free wheel the motor. Not the main 7/8" rear drive shaft. my thinking was to turn off one of the possibly 2 motors, if one was not needed. [saving power] Thanks to folks, like yourself, on this forum, I've been given other ideas to try like using the 3 spd.

as for the 7/8" axle freewheel - I had gotten luck and added a 20 tooth freewheel to the 7/8" rear drive shaft a few months back so the motor would free wheel. in general everything turned out great when I added the motor to the free wheel. even the motor mount was easy to make. in time, I learned that when climbing the canal bridge it strained the motor a bit. also then going against high head winds that strained the motor. That was the reason I want to use the 3 spd dual sprocket unit. lowering the gear from 3rd to 2nd will cut the speed a bit, but I feel easing the strain on the motor will pay off in the long run. again remember my rig is not build for speed, it's build to do work. Example: I carried 9 30pack cases on the trike a few weeks ago. [I got a lot of thumbs-up while doing that] Oh and that's another reason I want to add a rear disk brake. Not that workmans brakes aren't great, but they were not expecting people like me loading the trike with that much beer and removing the rear coaster brake to add a motor.

 

[JEB]

With all that weight over the rear wheels, I had that problem with my tadpole trike, standard tires, bike wheels, with lead acid batteries, my 200 lbs added to the trike, the weight over the single rear wheel was 360+ lbs. Then add some repair tools, a carry basket, a run to the store, lots of extra weight, hit a road defect caused the tire to have a cord break- I know this is over kill but I went to a 16" trailer tire with a solid rim, 3.5" of rubber on the road, 750# load rating, no problems anymore (so far).

 

[jeff peterson]

Check out my first page picture [2010_0119_210951AA.jpg] I have kexlar tires and two almost solid rims. not as good as yours but the roads here are almost perfect due to a Del Dot mandate for Delaware safety. Also all new planning must include bike lanes, got to love that! It is truly faster to cruise vai my slow trike than by car. do you have a pic of your trike?

 

[dumbass]

Da:

So why can't you change the shaft sprocket size to allow you to use a 13t or 14t freewheel?

I'm guessing my wording was not the greatest. I was wanting to free wheel the motor. Not the main 7/8" rear drive shaft. my thinking was to turn off one of the possibly 2 motors, if one was not needed. [saving power] Thanks to folks, like yourself, on this forum, I've been given other ideas to try like using the 3 spd.

as for the 7/8" axle freewheel - I had gotten luck and added a 20 tooth freewheel to the 7/8" rear drive shaft a few months back so the motor would free wheel. in general everything turned out great when I added the motor to the free wheel. even the motor mount was easy to make. in time, I learned that when climbing the canal bridge it strained the motor a bit. also then going against high head winds that strained the motor. That was the reason I want to use the 3 spd dual sprocket unit. lowering the gear from 3rd to 2nd will cut the speed a bit, but I feel easing the strain on the motor will pay off in the long run. again remember my rig is not build for speed, it's build to do work. Example: I carried 9 30pack cases on the trike a few weeks ago. [I got a lot of thumbs-up while doing that] Oh and that's another reason I want to add a rear disk brake. Not that workmans brakes aren't great, but they were not expecting people like me loading the trike with that much beer and removing the rear coaster brake to add a motor.

No I understood that you wanted to put the freewhell on the motor. I was talking about a "motor" freewheel adapter. That is why I explained that he smallest freewheel available is a 13t was because you said you needed to stay with a 9t. But of course there is no one that I know of that makes an adapter to fit the Currie motors. I am doing a simular thing as you whereas, I am putting the freewheel or freewheels on a jack shaft instead of the motor. But i do plan on making my own special freewheel adapters to fit on the Currie motors. But again the smallest freewheel made is a 13t so you have to deal with the ratio on the axal gear. Like you I want to try gearing the 2 motors differently. Maybe a 13t and a 15t or 16t. But at first I will gear them the same and see how i like it.

If you have a freewhell on the axal already can you install a second one for a second motor. that is something I am now considering if I have the space for it. I hope to get back working on my project late next week so I will know better if I have the space.

 

[jeff peterson]

Sorry this project got put on hold, good thing about a trike is that it takes up little garage space when standing vertical on it's rear wheels!

Thank you 12p3phPMDC for the link to Harriscyclery. I emailed them with my information and received a quick reply telling me the parts I needed and where they were on the website. Parts are now ordered, should be in Monday. I'll start installing next week.

Next on the list is buying a new battery. In about a month I'll get Tax money back from installing a solar electric system on the roof and I'm thinking of buying a Ping 24v 30ah battery. It seems most posts I've read, people feel this is a good way to go. Losing the SLA weight would be helpful since I often carry 600 lbs of passenger weight on the trike. I want to just plug the battery in, have it charge, unplug the charger and take off. I know nothing about BMS, I do not want to open the battery package and test things. I just want to climb on and go.... The SLA batteries are in good shape now and are working fine, but they will not go to waist, I have the iMow robotic lawn mower that uses the same 12v20ah batteries.

 

[12p3phPMDC]

Jeff,

No problemo, Harris is a great shop! I got a good deal on the Alfine 8 speed and other 3 speed parts as well.

RIP Sheldon.

 

[jeff peterson]

I received all the little parts I needed from Harris and everything fit perfect. Switching both the fixed and free wheel sprockets around on a 7/8" shaft took a little time. As well as making a motor mount. But it was just a bolt on removal and installation, so everything was straight forward. At this time the Trike is now back together with the [winter] flatbed removed and the [summer] Rickshaw rear seating reinstalled. I road tested the Trike last night by myself. [no passengers] With the 3 spd now installed with the input rear sprocket changed from 20 to 23 tooth, the 450 watt 24v currie motor goes about 6mph in 1st, 12mph in 2nd and 18mph in 3rd. I know this is slow for most people but perfect for my use. Most of my riding is on flat ground with only a train track overpass between myself and the main town. Sadly, I do not know how far I can travel on 24v 36ah SLA batteries, But since I plan to buy a 24v 30ah from ping shortly I'll wait and test things then. This weekend I'm off to Dewey Beach Delaware for a St. Patty's Day and local pub opening event. [during the winters the pubs are closed] Temp may hit 70 degrees and I'm sure many of the pub crawlers will want to ride from pub to pub on this electric 3 spd Rickshaw Trike.

I want to thank everyone that helped me on this site. If you're local to Delaware sometime please look me up, I'd love to let you try this EV.

BTW - The Trike did qualify as a 3 wheeled EV for a 10% tax write off of the total cost....
Thanks Again....

 

[torker]

Got any more pics of this build? I would love to see how you rigged up the 3 spd. hub.