rc motor project pics. new to the forum.

patrick.reavis

100 µW
Joined
Jan 26, 2013
Messages
9
Hi my name is Patrick and I am new to this forum. I have been looking at this forum for the last year or so and decided to try my luck at building an electric bike. I had a specialized hardrock sitting around collecting dust so I figured it would be perfect for my project. I started with a scorpion 5525 170kv (good for about 2600 Watts) and changed it form delta to wye termination giving me around 100 kv. Im sure I will lose a few watts by doing that but I am just trying to make my bike as efficient as possible and only want a max speed around 25 or 30 mph. I plan to use 4 zippy 6s 8000mha packs ( 12s 2p ) and one of those cheap esc's from hobbking. I have most of the hard parts done now I just need the electronics and batteries. Let me know what you think. I am doing this project with very limited tools (chop saw, drill press, files, and some thread taps).

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Looks real nice so far! I like the grip tape under the tube clamps! Should work well!
 
very clean, i'm impressed this was done with your limited set of tools you stated
 
Very nicely done! is that #25 chain in the reductions? If the ESC you chose survives, great. If it fries, you may not need a higher amperage (and more expensive) ESC. Its possible the same ESC with one added power-input capacitor would smooth-out voltage ripple (which can cause voltage spikes higher than system voltage). Many 12S users have had good luck with this $2 50V capacitor. http://endless-sphere.com/forums/viewtopic.php?f=30&t=22194&hilit=nichicon&start=45#p382837

I noticed that many bike frames today have an odd-shaped down-tube, but seat-tubes are consistently round, and with only a few diameters of tubing used. That means this design is very transferrable to other frames. Also, since this design is easily accomplished with garage-level tools, expensive machine shops could be avoided. Bravo, sir!

edit again: I haven't used my taps since I started using steel nutserts, drill a hole in the aluminum plate, slap in a steel nutsert with a smear of JB-Weld, assemble parts so the screw will hold nutsert in perfect alignment while it dries.

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Spinning magnets: those nutserts look good but wont you get corrosion from the alu and steel next to each other. I forget the correct term.
 
Galvanic reaction.
they make riv-nuts in aluminum also.
The steel units are plated in zinc which dramaticly slows the reaction to near neglagable levels in most applications.

the worst case senario is having them bathed in a ellectrolight solution (salt & water)
they are a joy to use.
 
Yes it is 25 chain. I wanted to use a belt drive but had a very hard time finding the parts to do it. For the esc I was looking at this one http://www.hobbyking.com/hobbyking/...160A_HV_Brushless_Speed_Controller_OPTO_.html I will add more caps. Does any one have any experience with it? I bench tested the drive train today using one of my rc plane esc's and a 24v power supply. It is very smooth and much quieter than I thought it would be, I know it will be much louder on 48v. It has tons of torque, in low gear it has a motor : wheel ratio of 30.33 : 1 at 48v I should get about 4500 rpm under load giving a top speed of 11.5 mph. In top gear the ratio is 10.42 : 1 with a top speed of 33.3 mph at 4500 rpm. Spinning the wheel all the way up at 24v only pulled about 40 watts peak in high gear. So the drive train seems to be very efficient.
 
btw aluminum shaft collars make perfect bearing carriers for those of you that dont have access to a machine shop.
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patrick.reavis said:
btw aluminum shaft collars make perfect bearing carriers for those of you that dont have access to a machine shop.
Brilliant (the above, plus the whole build). Thanks for sharing!
 
Yeah I like that idea as well! Very clever!
 
Based on many projects I have read about, you will of course need an HV ESC (will run 18V to 50V), and you will only need a 100A ESC with two added caps, and I would also recommend adding a fan.

If you want to risk saving a few bucks, perhaps try a Hobbywing, here's an HV-100A for $90 ( http://www.ebay.com/itm/HobbyWing-FLYFUN-Brushless-ESC-100A-HV-Version-4-1-/370743979792?pt=US_Character_Radio_Control_Toys&hash=item5652102f10 ). I have had an HV-70A for a while and it works good for me. The best is a Castle Creations ESC (I have a 18V-30V Castle ESC), which provides the added benefit of data logging. Downloading the info onto your laptop to read the charts is very easy.

Just checked, Castle has an HV-80A ($130-ish on Ebay), and an HV-120A ($190).

Could you post the part numbers and the supplier you bought the collars and bearing flanges from?
 
spinningmagnets said:
Based on many projects I have read about, you will of course need an HV ESC (will run 18V to 50V), and you will only need a 100A ESC with two added caps, and I would also recommend adding a fan.

If you want to risk saving a few bucks, perhaps try a Hobbywing, here's an HV-100A for $90 ( http://www.ebay.com/itm/HobbyWing-FLYFUN-Brushless-ESC-100A-HV-Version-4-1-/370743979792?pt=US_Character_Radio_Control_Toys&hash=item5652102f10 ). I have had an HV-70A for a while and it works good for me. The best is a Castle Creations ESC (I have a 18V-30V Castle ESC), which provides the added benefit of data logging. Downloading the info onto your laptop to read the charts is very easy.

Just checked, Castle has an HV-80A ($130-ish on Ebay), and an HV-120A ($190).

Could you post the part numbers and the supplier you bought the collars and bearing flanges from?

I used one of these to support the motor shaft http://www.vxb.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=bearings&Product_Code=Kit7230&Category_Code=16mmLinearMotionSystems . Just put a 16mm x 8mm x 5mm in it. I dont see a lot of people on here supporting the end of the motor shaft. I think it will take a huge load off the bearings in the motor. got all my bearings from that same website.

The other shaft collars I got form here http://www.amazon.com/Climax-Metal-H1C-081-A-Collar-Aluminum/dp/B007JOB324/ref=sr_1_22?ie=UTF8&qid=1359341354&sr=8-22&keywords=aluminum+shaft+collar . I just drilled and tapped them
 
Here is a like to where i got my sprockets, I know the ones for #25 chain can be hard to find. http://www.andymark.com/product-p/am-25sprockets.htm .
They also sell hubs to fit their sprockets http://www.andymark.com/Hubs-s/215.htm . I found their stuff to be very straight, true, and high quality.
 
I am now convinced that your drive would work well with the 80A Castle ESC (just read back over some older projects from the "year of RC drives"...

I dont see a lot of people on here supporting the end of the motor shaft. I think it will take a huge load off the bearings in the motor

I agree, I remember Grinhill's Mk2 drive supported both ends of the small pulley with bearings, taking virtually all the side-load off the motor shaft bearings.

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spinningmagnets said:
I am now convinced that your drive would work well with the 80A Castle ESC (just read back over some older projects from the "year of RC drives"...

With the way I have it geared so low the motor should never need to pull more the 40 or 50 amps so im sure the castle 80 would handle it. But I was thinking that by getting a controller rated at 140 - 160 amps the controller would not need to work very hard and not build up as much heat. I could be wrong maybe I would be better of to go with quality over quantity on this one.
 
When I changed the motor from delta to wye I decided to leave all 6 wires coming out of the motor so I can easily switch back to delta if I want a little more speed. I was thinking of doing the delta wye switching thing but with 8 speeds in not sure if there is much point in that. If anyone is thinking about switching their rc motor to wye give it a try its not very hard at all and it dropped my kv from 170 down to 98 and increases the torque big time.

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WYE not only lowers the Kv, it also is much easier on the controller (inductance?). If your amp-peaks are 50A, the 80A will easily handle it because you are giving the motor the use of the bikes gears.

I highly recommend adding a fan like the RC-car ESCs. They should be easy to find (I just went to ebay and searched "esc fan", many choices). ESC fans are likely 5V (can be powered by the built-in BEC or a separate UBEC), and small mainframe computer fans can be found using 48V (can be run at 44V no problem).

How hard was it to separate the wires to be able to make it WYE?

$12 for ESC case and fan http://www.ebay.com/itm/Castle-Creations-0100-Mamba-Monster-Replacement-Case-W-Esc-Fan-HPI-Savage-Flux-/121047243789?pt=US_Character_Radio_Control_Diecast_Toys&hash=item1c2efa5c0d

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It was very easy on my scorpion motor. I just cut off the factory bullet connectors and cut away the all the insulation. When I started untwisting the wires the 6 ends just kind of separated by them selves and it was very obvious where each wire went. I don't know if most motors are that easy, this is the only one I have ever done.
 
Great build. One comment/suggestion I would add though relates to your freewheel crank. In particular the fact that your using a single bearing ENO freewheel at this location. If you start having runout problems when not assisting the motor like many others have - myself included - I suggest you consider replacement with a dual-angular contact bearing freewheel of high quality - such as an ACS crossfire as sold by ES member 'MotoMel' on eBay.

See these threads for more info on the problems with ENO freewheels in Freewheel crank duties;

http://endless-sphere.com/forums/viewtopic.php?f=28&t=25153
http://endless-sphere.com/forums/viewtopic.php?f=31&t=40077
 
Any updates to this build? I would love to see how it turned out!
 
quick question, why the 3 stage reduction Vs 2 stage?
 
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