Rescue Motor - Aotema (Wilderness Energy BD-36)

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DrkAngel
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Rescue Motor - Aotema (Wilderness Energy BD-36)

Post by DrkAngel » Dec 06, 2017 5:46 pm

Last year, a guy traded me a bike with brush front hub motor, not working, of course.
Posted up a picture and got a probable ID as a Wilderness Energy BD-36s - circa 2005.
36V 600W rated.

Image
Tested motor with 8V and turned and sounded smooth so ... Winter project!

Image

1. Broken and rusted spokes.

Image
Re-laced with 13ga 188mm SS spokes (192mm more ideal)

2. Controller

After figuring out the 5 position switch ... I finally gave up on the controller and installed a 24-44V capable 28A controller.
24V YiYun YK31c that works fine at higher voltage, but with 50V caps, so 44.4V limit.
Cut motor wires near old controller and add XT60 connectors, from controller and to motor.
Added XT60's to Battery also.
Why the 24V controller?
Well, when testing motor with 8V, I did a count at 80rpm, that adds up to a no-load 32mph @ 36V.
Wanted "legal" ... option, ~ 20mph @ 25.9V.

3. Fork

This motor presents a particular quirk, hub motor is wider than typical.
Requires 3.5"+ fork width till several inches up fork.
Solid forks typically have pitiful brakes.
Only found acceptable option is a disc and rim brake hybrid fork (motor has no disc option).
Bike it came with had fork tubes crushed to provide clearance!
forked.jpg
forked.jpg (86.29 KiB) Viewed 244 times
Found a nice Schwinn bike that fills requirements ... but testing 1st, so on original bike, for present.

4. Battery

Just got a spare dozen 36V 4.4Ah Samsung hoverboard packs, so paralleled a few for testing purposes.
Since this was just a testbed I did not "properly" mount battery or controller.
Somewhere(?) I picked up a Nintendo Gamecube bag that works nicely.
GC1.jpg
GC1.jpg (141.14 KiB) Viewed 244 times
4 batts, 36V 17.6Ah fit nicely!
GC2.jpg
GC2.jpg (168.8 KiB) Viewed 244 times
Tested bike 1st with a single 36V 4.4Ah but kept below 25A draw, Samsung ICR18650-22p rate at 10A continuous 20A surge, so 20-40A capable. Possibly limited by 30A pack BMS?
Performed nicely.

5. Testing

Added speedometer and V-A-W-Ah meter
No-load speed estimate proved accurate @ 32mph.
Motor only, cruises at 23+, pedal assist helps greatly, but bike not set for proper pedaling, so no definitive tests.
Quieter than my chain drives ... too quiet, can't adjust speed by drive-train pitch.
Controller draws 32A full throttle-from dead stop till ~8mph, which seems to make it an acceptable controller. Larger controller would only help getting started, where I pedal anyhow.

Overall, motor seems wound a bit too fast. Would be great as assist for higher speeds!
Ideal, laced into a 20"?
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Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.

I enjoy enlightening ... and enlivening the spirit of the innovators.

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Drunkskunk
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Re: Rescue Motor - Aotema (Wilderness Energy BD-36)

Post by Drunkskunk » Dec 06, 2017 8:07 pm

All of those 1st gen motors are crazy quiet and smooth. They have that slant groove stator that eats some efficiency in trade for silkiness.

I bet that thing would be great in a 20"
Buy the ticket, take the ride.
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motomech
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Re: Rescue Motor - Aotema (Wilderness Energy BD-36)

Post by motomech » Dec 07, 2017 12:57 am

Several folks here have experience with the original Aotema, including dogman.
I believe it is still the smallest DD motor and has never been considered a powerhouse.
Terry, at;
https://store.hightekbikes.com/index.ph ... 0e8c1f2da9
still offers Aotema kits. I bought my first motor kit, a MXUS geared mini from him years ago and he was very helpful answering my Noobie questions, so I would recommend contacting him if you feel the need.
Motomech

'03 Rocky Mountain Edge 2WD 260 Q100H frt and Ezee V1 rear 2 Elifebike 20A & 25A 9-FET controllers 12S/20Ah Multistar Lipo rear 5Ah Turnigy frt Luna Cyclops Extra lite Alex 24DM rims, 2.4 Holly Rollers run ghetto tubeless. 25 mph. Mean Well HLG-320H-48A
https://endless-sphere.com/forums/viewt ... =3&t=83430
'07 GT Idive 4 4.0, Q100C 201 12S LiPoly elifebike 9-FET 17A controller. 20 MPH.
https://endless-sphere.com/forums/viewt ... 8#p1237928

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DrkAngel
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Re: Rescue Motor - Aotema (Wilderness Energy BD-36)

Post by DrkAngel » Dec 07, 2017 10:10 am

Based on oem specs, real life observation and a bit of imagination ...
I created a reasonable map representation of the BD36's power curve.
Though some values were altered, (most notably controller amps and tire size) ...
  • Power curve matches:
  • top un-loaded speed
  • observed top loaded speed
  • rated watts
  • Max controller drop-off speed
BD36 graph.jpg
BD36 graph.jpg (166.33 KiB) Viewed 154 times
Usefulness?
Alternate voltage effect:
10s = 3.9V per bank
Should give reasonably accurate power curves for my alternate 7s and 12s (present controller has 50V caps)
Alternate tire size effect:
29"
24"
20"
20" would provide best "legal" performance
29" would benefit greatly as a motor assist pedal bike
Pedal assist watt input enhancements?
Last edited by DrkAngel on Dec 09, 2017 11:01 am, edited 1 time in total.
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.

I enjoy enlightening ... and enlivening the spirit of the innovators.

New & Improved - Acronym Definitions

Index - Homemade Battery Packs - Updated - November 2015

EBike Toolbox - Bargains! $

Endless Sphere Wiki

User avatar
DrkAngel
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Joined: Dec 15, 2010 11:14 am
Location: Upstate-Western-Southern Tier NY. USA

Re: Rescue Motor - Aotema (Wilderness Energy BD-36)

Post by DrkAngel » Dec 07, 2017 2:38 pm

Yes 20" for 20mph @ 36V looks optimal!
Simply resizing by the proper ratio (36" / 26" x 20" = 27.7") I was able to plot motor with 20" wheel.
20vs26.jpg
20vs26.jpg (216.58 KiB) Viewed 116 times
Full throttle:
drops speed from 23mph >> (legal) 20mph;
improves efficiency from 72% >> 80%;
improves hill (below 12mph) and starting (35lb >> 45lb) torque;
increases range from 23 miles to 32 miles!!!

Proper 20" front wheel application is the problem!
Small 20" trike?
Will test alternate voltages before deciding anything ...
.
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There, shallow draughts intoxicate the brain,
And drinking largely, sobers us again.

I enjoy enlightening ... and enlivening the spirit of the innovators.

New & Improved - Acronym Definitions

Index - Homemade Battery Packs - Updated - November 2015

EBike Toolbox - Bargains! $

Endless Sphere Wiki

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