Rescue Motor - Aotema (Wilderness Energy BD-36)

DrkAngel

1 GW
Joined
Dec 15, 2010
Messages
5,300
Location
Upstate-Western-Southern Tier NY. USA
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.

27367130_aa46dac194.jpg

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

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1. Broken and rusted spokes.

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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

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

4 batts, 36V 17.6Ah fit nicely!

GC2.jpg
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, slower than 9mph, 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"?
 
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.php?main_page=index&cPath=2&zenid=14f7fe987628ecbd1cd05c0e8c1f2da9
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.
 
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

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?
 
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

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 ...
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The BD-36's power map is no longer typical!
Compare above output graph to a more typical (modern) motor's power profile.

(output profile that matches my eZip's 450w gear reduction motors)
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The more common profile uses a higher-lighter winding to produce maximum motor output at closer to maximum speed. Higher voltage-lower amps allows thinner, lighter weight, cheaper, copper windings ... with the same power output watt rating!

The lower Amp regulated controller effectively "cuts off" the possible mid speed bulge of power. Required to limit the overheat potential of the thinner, light gauge, windings.

This propensity for higher voltage-lower amps has the additional-useful purpose of limiting a motors watt output, for legal purposes. This Amp limiting can extend a motors maximum watt output for a much broader percentage of it's useful rpm! Additionally, this provides maximum watt output near maximum speed for optimal speed x efficiency = performance.

Whereas the BD36 provides a more modest top speed but with a comparatively enhanced reduced speed "hill climbing" capability.
 
No, they suck for climbing hills at low speed in 26" wheel, the BL much better. The culprit is the extra heat caused by the brushes, and once you toast a set of brushes, then the motor really melts itself down. The motor is wound fast, comparable to a 6 turn 9 continent, making it too low rpm on grades above 4%, in 26" wheels. Keep it short, and I'll buy what the graph says, but climb a long hill with that brushed, and you will melt er down. When those motors were sold, people ran lead, and no ride ever lasted long enough to melt the motor. Cold enough weather though, no problem.

28 amps of 24v should be fine for "normal use" though, just don't load it up and try to ride up long steep hills by bumping to 48v is all I'm saying.

It should stay well within its limits running in a 20" rim of course, because you wont be at such low rpms then.

Graphs are cool, and very useful, but I would avoid saying shit like its great for hills at low speed, till you do some of it and melt a few motors. That lie about better for hills is part of WE's bullshit advertising. THEY DO run better on 24v than a brushless we, but they (brushed aotema) melt down easy as pie on 48v,(1000w) while the brushless version can handle 2000w pretty good. Keep that brushed motor below 800w IMO, if you plan on any hills more than a half mile long.

That motor could run hard for years in other places, shorter hills, cooler weather. My problem is I live near some real mountains. 3000 vertical feet from downtown to the pass in the picture. When it got above 90F, I could melt the motor on a 15 mile ride on shorter hills. In summer, I learned to drive or bus half the way home from work. 9 miles in summer no problem, 15 would melt my motor. Leaving the house..jpg
 
I tow a trailer now for cargo like groceries, and lost interest in sleeping in a tent on a tour.
 
Looking to test at 25.9V.
Have 25.9V 5Ah LiPo, can parallel a couple together, drop in bag and test drive.

37V vs 25.9V

36vs25.9.jpg

Looks to supply moderated torque, speed and watt usage\output.
At ≤17mph looks to be reasonable for eTrike or comfort bike.
Either should supply adequate brakes!
Nice speed for casual-prolonged cruising with modest assist on local lazy rises.
 
LVC on the stock WE controller was right about 24v. So you might find 7s is what you need to really run it. It will test ok on 6s, just not run till the batteries are empty. On 24v lead I was getting about 15 mph, ideal actually for that Schwinn trike.
 
dogman dan said:
LVC on the stock WE controller was right about 24v. So you might find 7s is what you need to really run it. It will test ok on 6s, just not run till the batteries are empty. On 24v lead I was getting about 15 mph, ideal actually for that Schwinn trike.
Well, replaced oem controller ...
New, multi-compatible, controller has 20-21V LVC and should work nicely with my new Samsung cells (7s) that I rate as empty at a static 3.4V.

DrkAngel said:
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.
I have a Schwinn Meridian or a Kent Alameda as possible eTrikes.
But nice 26" [strike]Ladies[/strike] LS (Low Step) with big comfy low slung seat, high bars, big tires and silent motor, sounds ... attractive.
Walmart has clearance on several big soft seats, so ordered a few to test.

25.9V Lithium should be a noticeable torque-speed-range-weight improvement over 24V Lead.
New controller is multi compatible 21V LVC and tested from 22.2V pack through 12s 50V (has 50V caps so limited charge ≤ 50V)
And, can always swap on 36V pack if get bored or need to be somewhere faster.

I will test 25.9V motor rig to determine actual motor output, to compare to ebikes.ca simulator.
 
Look at the ladies Schwinn candis at WM. Its a cheap version of the pedal forward townie.

Its tricky, but possible to convert a trike to a very low slung bike. But it is low, low enough to pedal strike on corners. and no rear brake.
 
25.9V version @ 300w looks to be a diminutive output compared to 600w from 37V! ... ?

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I will try to determine actual motor output by using an observed 50% efficiency @ ~50% of no-load speed.
Full throttle @ 37V, motor will draw 1200w for 600w motor output @ 16mph ... attached V\A\W meter will confirm Watt usage.

Ebikes.ca simulator indicates-estimates:
25.9V no-load speed as 22mph
Full throttle @ 25.9V, motor will draw 600w for 300w motor output @ 11mph ... ?

Actual % of no load speed is not precise but using the same percentage on same motor at different voltages should be accurate, for comparison purposes.

1st ... Will have to check-confirm 25.9V no-load speed!
 
yep, its pretty gutless on 24v.

But on 36v, I had to stop by 10 miles in summer, because on the hills I had to climb, 15 was too far. I did a lot of bike to the bus that summer, to avoid that hill. Would have been fine if not for the 1000 feet of vertical though.
 
.
...
Wilderness Energy (Aotema) BD-36 36V 600w front hub motor

Local terrain consists of fairly level streets and trails ...

Best application possibilities: - recommended possibilities - so far ...

37V 26" wheel
Cruising at ≤23mph
Pedal assist with ~25mph capability (front hub is ideal as assist power. Better acceleration and higher sustainable speed.)
20mph cruising with manual throttle restraint [strike](WOT)[/strike]
Place potentiometer in-line on throttle to regulate top speed to 20mph (TURBO switch bypasses when advisable)

25.9V 26" wheel
Cruising at ~16mph
Assist for varied terrain
#1 Casual cruising on comfort bike
Lackadaisical commuter or
Assist on loaded upright trike

37V 20" wheel
Cruising at 20mph - ideal, but limited applications
20" trike
20" folding bike
FWD for child's bike seems too dangerous?
(Upstate NY pothole season makes small wheels ... risky)

I have no real objection to 23mph capability ...
But am acquainted with 20mph capable rigs or with motors loud enough to regulate speed by tone. The WE motor is exceptionally quiet and the 23mph WOT is a severe efficiency and range detriment! Not "legal" either.
 
That motor, in 26" wheel runs good on 36v. Problem is if you slow it to 24v for a safe and sane speed trike, it gets gutless, on original controller. That is fine, if you have no hills, or hills are less than 3% grade.

Decent motor for less extreme places than I live, like a beach town, for a 36v bike. 48v, and it hauls ass, 30 mph.

24v 40 amps on a 26" trike would work fine, ( almost 1000w, so not gutless then) or 36v 20 amps on a 20" trike.

When I ran it 26" and 48v on a Schwinn trike, it was crazy dangerous. But if you have self control, you can still ride it safe. I just had no self control. :roll: 15 mph is the top safe speed on those trikes, any faster steering is compromised.
 
.
...
I decided to post up charts for 10s + 9s and 8s + 7s
Charts are for WE (Wilderness Energy - Aotema) 26" wheels and 32A max controller
Please remember! ...
DrkAngel said:
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
37V & 33.3V - I have 33.3V 43Ah battery

10s9s.jpg

29.6V & 25.9V - Have many 25.9V batteries

8s7s.jpg


Nearly precisely 100w motor output and 2mph top speed lost per "1s" (3.7V)

Just for S&G ...
22.2V & 18.5V

6s5s.jpg

.
 
dogman dan said:
Decent motor for less extreme places than I live, like a beach town, for a 36v bike. 48v, and it hauls ass, 30 mph.

OK ... OK ... will post up 13s +12s charts

48.1V & 44.4V



13s12s.jpg

I enabled the "MTB Tuck" load line which demonstrates 28mph and 30mph - motor only!
Limiting controller down from 32A, towards 20A, should help motor survive with no loss in top speed.

.
 
Settled on 3 26" possible applications:

25.9V 300w cruising at 16-17mph
Several 25.9V batteries on hand
casual speed for lackadaisical meandering
or
eTrike max speed

33.3V 20-21mph commuting
Large quantities of 3s batteries make 33.3V 9s builds desirable
20mph "legal" speed with enhanced efficiency and range, compared to 10s 37V

44.4V 27-28mph traveling
Large quantities of 3s batteries make 44.4V 12s builds desirable
Near 30mph capability!
Testbed for fairing or max-crouch trials
reduced charge voltage improves battery life and is capable with 24V controller (50V caps)

Any will run off the presently attached 24V YiYun YK31c controller. So can swap batteries for desired performance!
9s20p 33.3V 43Ah battery might not get recycled yet!
1438mAh battery should provide (motor only):
60 mile range @ 20mph
90 mile range @ 15mph
 
Trouble is,, your charts are for a clyte 408, which is similar to the 407, WE brushless motor.

This is not even close to similar to the brushed version of the WE (brushed aotema). Right out the gate, the brushed motor behaves very different under heavy load, building up heat a LOT faster. And even lightly loaded, it is about 20% less efficient than the brushless motors. That is where the heat is coming from btw, and once hot, performance drops off much faster than a hot brushless.

Clyte used to make a brushed motor as well, nearly identical to the aotema brushed, but I don't know if Justin ever had one on the dyno to get data for the sim on it.

In any case, you are waaaaaaaaay off trying to guess the performance by simulating a completely different type of motor.

Nevertheless, if you don't try to climb hills that are 15 miles long in summer like I did, they can make an ok motor for an adult trike, if speed is limited by running it at 24v. Or bike at 48v, just so long as the terrain is not so long and steep. I'd say 5% grade is the limit for this motor, while the 408 can climb 10% easy, or more.
 
Performance chart was chosen-modified to match the actual, observed performance.
Curve is accurate on 4 points, 3 should be reasonably accurate, 4 being a whole level of accuracy higher!

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 - no load, full throttle speed
  • observed top loaded speed - matched real world level cruising speed
  • rated watts - close to oem rated 600 watt output
  • Max controller drop-off speed - Draws full 32A till 8mph, which matches!
Additionally, motor chart indicates a 80% possible peak efficiency with an actual ~75% efficiency at top speeds, which compares within the range of typical brush motors.

Regardless ... 37V graph seems accurate with observed, (excepting unknown actual efficiency percentage).
Which should make altered voltage comparisons reasonably accurate on speed and torque. ... ?

Heat is a minimal to non factor in my suggested applications, especially considering local terrain.

My graph comparisons were specifically drawn as voltage and gearing comparisons rather than actual-accurate performance, though ... should prove of reasonable accuracy. ... ?
 
I see, I did not realize how much you tweaked the inputs to get those graphs.

I just relied on 3000 miles of riding one for my opinions, with a temp monitor inside it after I fried the first one. They heat up crazy fast, like many brushed motors that don't have vents and fans.

All I'm really trying to say here, is they overheat fast on a hill, or any other condition of heavy load. And they run too high rpm on 36 or 48v for any use on a trike. So again, great motor for those who live where its flat, and don't otherwise overload it. Run it on 24v and 30 amps should work good for a trike where its flat. Bike I'd suggest 48v, because then it is a very fast ride. But like other fast winds, not an efficient choice if you have lots of inner city starts and stops. 9 miles of that at 48v, and you are pretty darn hot. When this motor was in use, the lead would die before then, solving the problem. I got into trouble trying to do 15 mile rides home.

When I dumped the brushed, I could stop riding the bus with my ebike, and ride all the way home in summer.
 
dogman dan said:
Look at the ladies Schwinn candis at WM. Its a cheap version of the pedal forward townie.

Its tricky, but possible to convert a trike to a very low slung bike. But it is low, low enough to pedal strike on corners. and no rear brake.
Spotted a Schwinn Candis on the top rack.
"Clearance $69"!!!
Snagged the last one and took to the register ... scanned at $49!!!!

Front fork is steel and appears of proper width. (Aluminum frame)
Strange quirk is single brake lever ... for rear and front brakes. Right side rear brake pad slides forward under moderate application engaging the cable to the front brakes. ? Might work OK but will require constant monitor and frequent adjustment?


Schwinn Candis.jpg

"Video" explains Dual brake system.

Went back and scoured the racks for another ...
... found Kent "High Roller" 700C commuter @ $39 ... couldn't pass it up!

.
 
Trying the WE motor on the Schwinn Candis. Tabbed washer (oldytime torque arm surrogate) doesn't work properly with lawyer lips.

On the non-wired side, after experimenting with various attempts to use tab washer, discovered that ...
M12 split lock washer works as a nice solution for lawyers lip!

Used proper torque arm. Did use U washer on wire side, wires exit inside bottom tang of fork.
 
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