Why not friction drive?

[EVTodd]

Just found the specs on the 380. Looks like they only put out about half of what the 540 does. Maybe I'll try to put the 540s on that mount. I'll have to drill and tap new holes for mounting the motors since the spacing is different. I'll also have to make the holes on the motor gears a bit bigger since the 540 has a bigger shaft. I hope there is enough spacing between the two motors to even fit twin 540s. You would need a little over 1/8" to make it work.

Of course I'm assuming those little gears can even handle what I'm about to try with them. I may have a few Mabuchi motors for sale shortly (at least they're cheap).

 

[recumpence]

I think the data on that mount are wrong, though. Those two motors sure look like 540s.

Matt

 

[EVTodd]

You're right, it does look more like 540s.

If you parallel four 540s to one controller how many volts would the controller need to be? I assume 48 if the 540s can handle 12 volts (48/4=12).

Here's the controller I'm looking at: http://cgi.ebay.com/48V-500W-brushe...11332QQcmdZViewItemQQ_trksidZp1742.m153.l1262

I'm probably going to give this a shot but I have a bad feeling the efficiency might suck with small brushed motors like this.

 

[recumpence]

You are thinking series. If you run them in series, the voltage would need to quadruple. If you parrallel them, the ohm rating would be divided by 4.

Matt

 

[EVTodd]

You are thinking series. If you run them in series, the voltage would need to quadruple. If you parrallel them, the ohm rating would be divided by 4.

Matt

Ok, that makes sense. I wonder if the 540 could handle being run off of a 24 volt controller.

 

[recumpence]

540s run best at 8 to 9 volts. They will run up to 12 volts, though. But, their life span will be shortened a bit.

Also, remember, you could also series-parallel them. That way each motor could be run at 12 volts. Heck, you could series them all at 36 volts and get them right close to their perfect voltage range.

Matt

 

[mvadventure]

Having used a Z.A.P. 12 volt 20 AH system for several years on my steel Jamis Boss cruiser (beach bike) for several years I feel qualified to comment. One of the big advantages was simply the ability reach back and disable the cam holding the drive wheel against the tire thus eliminating any drag when the power assist isn't needed.

For a year or two I rode about 12 miles each way to help on Habitat for Humanity projects. Since I live on the ocean this meant the breeze would be coming from the west in the mornings (in my face) and from the east in the afternoon (in my face again). The ride each way would take an hour and be exhausting in the afternoons after working all morning. The Z.A.P. seemed a way to help fight the wind and especially the bridges.

About $400.00 later and a hour or two installing it the system proved not only workable but a lot of fun. With no pedaling I got 8 MPH which is VERY slow but with pedaling it was really easy to maintain 12 - 14 MPH without breaking a sweat and going up the bridges was a snap. If there was any slippage on wet roads I never noticed it. I also found that the more I used it the more dependant I became on it. The good news though was even though my SLA battery would get weak there was always enough power to get me over the last bridge on the way home even if I had to pedal a little harder. Since the Z.A.P. system employs only a simple on and off switch there is no controller and no throttle, the battery will go until dead.

Naturally range coupled with power became a concern and a little experimenting coupled with five or six dollars worth of wire and a switch at the local auto parts store along with a spare battery enabled me to simply unplug one battery and plug a fresh one in. This required stopping the bike and spending fifteen seconds making the necessary connections.

I used this system for about eight or nine years and probably over 3,000 miles and while the drive gear showed a little wear the original rear tire showed precious little more than the front tire.

Upgrading to a Phoenix Cruiser however enabled me to forget how to pedal and further upgrades to LiPo4 batteries meant I could go a long way very fast. I sold the Z.A.P. system on eBay at a good price to a satisfied customer. The funny thing though is even with upgraded new tires on the bike once the Phoenix system was installed I wore a high performance 2.0 slick down to the thickness of a cigarette paper in less than three thousand miles with the rear tire in almost the same condition.

Mostly though it took several years to get 3,000 on the Z.A.P. and I put that many each year on the Phoenix! When I'm caught in the rain though I'd gladly trade back 'till it quits raining.

Mike

 

[etard]

Thats exactly the field story I need, MrAdventue! Thank you!

Now looking at the rollers that came for the goped, I was wondering if impregnating the roller with diamonds wouldnt work. Much like the saw blades that they repair and reuse. The goped rollers are .600" and .850", the rough traction area on these are rough like a file or sandpaper, but I can see how they would wear down before the tire. The good thing is, they are only $5, so maybe I will get a few to experiment with different motors.

Physics quiz: If you have a 26" wheel against a 1" wheel, will it have a bigger contact area than a .600" wheel? Taking into account the flexing of the 26" wheel.

 

[EVTodd]

I picked up a couple of those dual motor geared rc motors. They are indeed the smaller rs-380ph motors. I'm not sure if even 2 (4 motors) would be enough to push a bike.

According to Mabuchi's web site they are 12 volt (I have a hard time believing you can run them at 12 volts), 45 watt max motors so that's only 180 watts before you figure in the losses. Of course, it's a 3:1 gear reduction so that would help the torque some.

Here are the motor's specs: http://www.mabuchi-motor.co.jp/cgi-bin/catalog/e_catalog.cgi?CAT_ID=rs_380ph They are the more powerful version that can only spin ccw (which kind of sucks for using one on each side with friction drive, would need 2 rollers instead).

I dunno, what do you think Matt (or anyone else)? With the reduction would it be worth messing with in your opinion?

 

[etard]

I would say get a cheap rc ESC on ebay and put it on a kids bike, and you might have a nice mini system.

I just got my RC Smart (ebay) 560 kv motor and DAMN this thing is small. My first thoughts are to upgrade to a bigger motor, but I'm going to try a simple direct drive first, i.e. motor shaft welded onto the .800" goped roller. I'm not using the EV Warrior roller, as it will require gear reduction with this motor. Besides, it weighs like twice as much as the little outrunner. RC Smart motor came packaged with an 80 amp controller, which I will take to 30 amps max. I'm waiting for a 24 volt 13ah nimh battery which I will run the system with. Total system weight should be around 5-6 pounds + battery. Also, all the weight will be sprung weight, preserving flickability and handling. At about 20mph the lil motor should be screaming at around 12,000 rpm, but that should be an efficient speed, I hope. I will post pics later this week. Thankfully, actual fabrication can now begin.

 

[EVTodd]

I finally broke down and picked up a Castle Creations Phoenix-85HV slightly used for around $100. I'm planning on using it with is motor:

http://www.hobbycity.com/hobbycity/...werPro5330-10T_679g/215kv/80A_Brushless_Motor

I will probably start with 24 volts of nicads. Does anyone see any problem with that combo before I buy the motor?

 

[etard]

Congratulations on your Castle purchase, sounds like you got an excellent price on it. I just got mine (HV-110)in the mail from JohnRobHolmes, and it is amazing the difference in size compared to my far inferior Wilderness controller (too bad you can't shrink batteries with better programming too).

That motor seems nice, at least the reviews are all very super positive!!!!!!! It makes me wonder, if the site doesn't have people inhouse writing all those 5 star reviews. Besides that, the risk is small at less than $50. Some of the cheap outrunners on that site have japanese bearings, I don't know if thats worth an extra $20-$30 though. If you run the warrior roller, it only gives you 20 mph no load. What does that translate to in real world speed? Double your voltage and you should be fine. But that's why you got that controller isnt it? haha

How are you doing your throttle?

 

[recumpence]

Becareful increasing voltage on RC outrunners. Most of them do not tolerate it.

Anyway, you can always run a larger roller. :wink:

Matt

 

[EVTodd]

That motor seems nice, at least the reviews are all very super positive!!!!!!! It makes me wonder, if the site doesn't have people inhouse writing all those 5 star reviews.

I thought that about the reviews too. I have, however, seen some bad reviews of some of the cheap escs and other outrunners. Like you said though, it's not a real expensive motor so I'm willing to take a chance on it.

If you run the warrior roller, it only gives you 20 mph no load. What does that translate to in real world speed?

How are you doing your throttle?

I will probably use the same 2" aluminum sleeve I currently have on my Kollmorgen setup. That would put the no load top speed at 30+ mph at 24 volts (way faster than I need). I'm guessing with the amount of power that motor can put out it should be realistic to get close to that in the real world (or am I nuts?).

As for a throttle, I plan on using a cheap chinese hall throttle (using a 5v voltage regulator from the batteries) wired to a servo tester. I will also use a kill switch on this project for sure. I had a hall throttle stick wide open a while back.

Becareful increasing voltage on RC outrunners. Most of them do not tolerate it.

Anyway, you can always run a larger roller. :wink:

Matt

Matt, I think that motor can run a lot higher than 24 volts. I'm still a newbie when it comes to all the rc battery terms but the spec sheet for that motor shows the recommended batteries at 10 lipos. Wouldn't that be 42 volts?

Hobbycity doesn't show how many volts it can handle but it says this: "Max Power (W/60s): 2800" what does 60s mean?

Given the data they list do you think I would get decent power from that motor at 24 volts?

 

[etard]

I would suggest plugging your values into SwBluto's ebike calculator. I put my current information in, I figured out that to get the speed I want I am gonna have to go 48 volt. Gearing alone wont cut it, it just makes the motor less efficient. Right now I have a 295 kv Exceed-rc Monster Power 110, Astro flight servo tester, CC HV-110, EV Warrior roller, and a 24 volt 13ah nimh battery. I need to figure out the BEC, and get more battery, and get the belts n pulleys

 

[EVTodd]

I would suggest plugging your values into SwBluto's ebike calculator. I put my current information in, I figured out that to get the speed I want I am gonna have to go 48 volt. Gearing alone wont cut it, it just makes the motor less efficient. Right now I have a 295 kv Exceed-rc Monster Power 110, Astro flight servo tester, CC HV-110, EV Warrior roller, and a 24 volt 13ah nimh battery. I need to figure out the BEC, and get more battery, and get the belts n pulleys

I will have to try that calculator. Do you have a link to it? What kind of speed are you trying to get to?

I think I've finally pinned down my goals for this current project even though I have to admit those goals tend to change from day to day. I really want a super lightweight short range (enough to get to work and back) bike that has potential to be upgraded if I feel like it later (or find good deals on batteries).

If I can get a top speed of around 22 to 25 mph (with the same or more torque than the Kollmorgen I have) I'll be happy. To be honest, I think anything above that is a bit crazy on a normal bike but it's amazing how fast you get used to even higher speeds.

I'm torn between these two motors right now:

http://www.unitedhobbies.com/UNITED...werPro5330-10T_679g/215kv/80A_Brushless_Motor Would the 10 or 9 turn version of this have more torque?

or this:

http://www.unitedhobbies.com/UNITED...63-54-A_250Kv_Brushless_Outrunner_(Eq._52-20) Could my 80 amp castle controller handle this motor at 24 volts?

 

[etard]

WOW! I didn't realize how cheap those HXT's are. Cheack out http://www.nitroplanes.com and you will see that my motor is exactly the same (different paint) as the 250 kv (mine is 295 kv)motor, the picture is of the other side. However, rather than waiting almost a month for the motor, I recieved it 2 days after ordering, and I am happy with the finish. I think it is either a knockoff of the E-Flite power 110 motors, or same motor, different color. Those HXT's are kinda ugly, huh? It is a very sturdy looking motor, except it only has front mount, my smaller outrunner with through motor axle has both side mounting. The windings don't look like a 5 year old wound it, but then I have never seen an AXI or Pletti up close to compare.
From my understanding, the higher the pole count the more torque capability because the controller can fire more pulses of energy to the windings per revolution with less cogging, but I could very well be wrong.

 

[etard]

OK,I am reviving this thread because I have some new ideas. Any input on potential problems or ideas would be awesome.

I bought one of these:

It's an SRAM 3 speed hub. I plan on using this as a roller which I can change the speed of by changing gears, giving me 1.75, 1.00, or 1.33.
Now the hard part... I want to bond a tire tread to the roller that matches the indentations of the tire for maximum torque without slippage. I need a tire with continuous tread pattern. I was thinking the Maxxis Holy Roller might be the easiest to do this with. Check it out:

I could cut off the roller tread as desired to match the tire. I was also wondering if a V shaped tread pattern might be quieter, or engage better. Like these:

I am going to order a 5mm pitch belt with a 2:1 ratio. I think I can do this with a 12 tooth- 24 tooth from McMaster-Carr, without having to go through SDP-SI.

Anybody see a problem with this logic? :?

 

[Rassy]

I think your plan might work pretty slick. I like the idea of being able to shift gears. But, I would worry about using such as aggressive tread, since it might be all but impossible to match perfectly on the small "roller" there would be times when a whole "tooth" has to slip by. That could cause a funny jolt each time. But I say go for it and good luck.

 

[GGoodrum]

Interesting idea. I don't think I've seen anything like this posted before.

FYI, the ratios on the SRAM 3-speed hub are 0.75:1, 1:1 and 1.33:1.

-- Gary

 

[deecanio]

interesting indeed, how many of those "knobbys" do you think would interlock at a time? they wouldnt be too strong mind unless the compound was very hard?

Cheers,

D

 

[etard]

That's a good point D,
I would think that the friction of both surfaces mirroring the other and interlocking would have a better effect than a flat roller against a smooth tire.

By the way, Urban Assaulters, JensonUSA is selling the 26 x 2.5 Maxxis Holy Rollers for $22. I am gonna have to check my bike to see if these smooth rolling tires will fit.

 

[etard]

I placed an order for one of these 14 tooth steel pulley for the motor:

Then I will attach this 28 tooth pulley to the freewheel sprocket:

I got 2 belts in different sizes, one is Kevlar, the other is Fiberglass. I went with 3/8" pitch, 1/2" width.

I am ordering the Holy Rollers, but I have to get 2 so that I can cut one up for the roller.

Any ideas on how to bond or attach the tire to the roller I was thinking about scuffing up the SRAM and just finding an epoxy that doesn't eat tires.

 

[Bobocop]

Any ideas on how to bond or attach the tire to the roller I was thinking about scuffing up the SRAM and just finding an epoxy that doesn't eat tires.

I would think that you have a better chance of glueing rubber to rubber (tire) then rubber to metal.

You can maybe try putting a couple of groves on the roller (and scuff it up) then melting a piece of rubber to it, (rubber melts to metal good) this way it will be a nice tight fit and it won't slip,
Then you can glue another piece to that. (rubber)

Just an idea

 

[deecanio]

etard,

what size holy rollers do you need??
bear in mind they are fairly soft tyres too.

Cheers,

D