Turnigy 80-100 RC drive VS Bafang BPM Hub

Kurt

Kurt

10 kW
Joined
Apr 21, 2008
Messages
962
Location
South Australia
I will start off saying yes we all know even the biggest of the geared Bafang motors are still girly little motors and the 80- 100 has huge power potential that would fry the Bafang. I understand that. The point of this comparison is not to see what motor is the ultimate power beast. It's to compare the two drive systems under identical conditions. By this I mean Bike, wheel size, tyre, rim, battery, controller, rider are all identical, the only thing that changes is the motor. Swap one into the trike and then the other. Plug the phase and hall plugs in and it's good to go.

Weight difference between the two is minimal. The Bafang is 4kg and the rc system is 4.25kg +.5kg for the wheel hub 4kg and 4.75kg respectively so there's only 750 grams difference. So let's just say they weigh about the same.

Bafang weight
6993c2ad.jpg


RC drive weight + 500g for wheel hub
e70f62f0.jpg


Weight balance is about the same too. The rc drive has its weight centred more in the trikes frame but a little higher up in the frame. The Bafang motor sits with 50% of its weight below the axle line and 50% above but to the rear of the trike. The bafang gives me the ability to place the battery behind the seat where the rc drive would have been, so in the end I think the Bafang would have the edge for weight balance. But for now when riding the trike the seat of the pants feeling is very similar.

Pic of RC drive
IMG_0814.jpg


Pic of Bafang BPM in identical sun rim and tyre to rc drive
IMG_0862.jpg


For my test they are both being fed 15s 25c 10ah pack of lipo 58 - 60v and driven from the same 12 fet 45A controller so around 2500w max. Some will say 2500w will kill the Bafang but I have tested it and under general riding with bursts of power when you need it the motor is only warm after a 10km ride. The gears and the motor in general are given a much easier life when laced into a little 20" wheel and I think this is the key.

This weekend I will have a chance to repeat previous rides that I did with the rc system that I have extensive data on already. I can then compare the two in detail and post up the results. I will also include things like DB reading at different speeds for people concerned about sound.

Anyhow I just think this is going to be a great chance to test the two very different yet similar in a lot of respects. They are both fixed gear reduction and both free wheeling and identical weight. Tested under identical conditions. How a comparison experiment should be conducted really I think.

Don't take this next two videos as a fair comparison, they are just interesting pre test fun videos.

from the 45sec mark. This is a video of a little section of road that I took footage off with the trike at 60v 45A START THE VIDEO FROM THE 45 SECOND MARK
[youtube]ehN5pbE16o4[/youtube]

This is the identical section of road starting and stopping at the same point and following the same track. Bafang BPM 60v 45A. Now why it isn't a equal comparison is I was also towing a child trailer with my daughter so an extra 32kg holding me back!!!! The extra drag of two more wheels and the wind drag is considerable. Interestingly the bpm was only 4 seconds slower 2:14 vs 2:18 over the same track. That's not bad considering there is a HUGE incline on the test track and I am towing a trailer and extra person. I will do the same test without the trailer on the weekend I think the Bafang will a little quicker.
[youtube]n2YoOJyiaSU[/youtube]


I will get back with all the data on power consumption, heat, noise by the end of the weekend when I have ridden the two 35km and then 45km test tracks. Just For kicks I will do 0-20 and 0-35mph times.

Kurt
 
LOL AJ if I decide to sell it you have first dibs.

I am not saying the Turnigy is no good. Just the Bafang has a lot more punch that I was expecting when you limit them to 2500w. I am trying not to be favouring one or the other for the tests. It just could be helpful for people looking into both style of geared motor drives.

I love the look of the rc drive and The potential for big power. Yet 2500w for general riding and a bit of range from a battery is still fun for 90% of my riding.

Kurt
 
Kurt said:
... The point of this comparison is not to see what motor is the ultimate power beast. It's to compare the two drive systems under identical conditions.By this I mean Bike, wheel size, tyre, rim,battery, controller, rider All identical the only thing that changes is the motor. Swap one into the trike and then the other. plug the phase and hall plugs in and its good to go.
...
This weekend I will have a chance to repeat previous rides that I did with the rc system that I have extensive data on already. I can then compare the two in detail and post up the results. I will also include things like DB reading at different speeds for people concerned about sound.

Anyhow I just think this is going to be a great chance to test the two very different yet similar in a lot of respects. They are both fixed gear reduction and both free wheeling and identical weight. Tested Under identical conditions. How an comparison experiment should be conducted really I think.
...
I will get back with all the data on power consumption, heat, noise once by the end of the weekend when i have ridden the two 35km and 45km test tracks. For kicks I will do 0-20 and 0-35mph times.
Click to expand...

What a test plan! Can't wait for the test results. Thanks for doing this.
 
This is the 35km test track. Its a good mix of terrain. Includes a big climb to a lookout, undulating small hills and some nice flat bike paths along a highway.

5992226831_0b08347240_b.jpg


I will be logging the ride on my Iphone usng Bikemate GPS logger and whr - km max, amps, speed and so on will be logged with a calibrated cycle analyst.Temperature will be recorded with infra-red digital temp Gauge.

Rider weight and total bike weight will be recorded with and without battery.

The only variable will be riding style so I will do my best to keep tabs on this but I tend to be very consistent in my riding and peddle input or perhaps I could just not peddle at all?

If anyone can think of anything more let me know .

Edit: last time I did this same ride with the rc drive I did it at 38v -20 ah headway pack. Considering the distance I might have to do it on this pack again as my 60v lipo is only 10ah. My thoughts on this regarding the two motors are the bafang even though its a code 9 has a lower wheel rpm - volt than the RC drive at 38v the RC drive tops out at about 38kmh and the Bafang at 38v would be 32kmh. So .84 kph - volt for the bafang and 1 kph - volt for the RC drive . This is the one variable I cant change. At 60v the rc drive will do 60kph and the Bafang 50kmh.The only way i can get them 100% equal is to change the motor sprocket on the RC drive and in the future I will calculate the necessary decrease in tooth count although it could end up to small and have belt contact patch issues. Alternatively and perhaps a better option is to increase the tyre profile on the bafang wheel to give them the same top speed . Perhaps all this isn't necessary? I just like to conduct test in a apples for apples way.

Another option is to limit the top speed to 32kmh through the CA for 38v testing and 50kph for 60v testing?

Anyhow I am off to get a temp gauge this morning and charging my packs and will set off just After lunch.

EDIT:I had some things to do with the family today and didn't get around to doing the test ride. I did go on a small 15 km ride today just for fun and will do the tests on Sunday now.

Kurt
 
Cool test Kurt, I'm interested to see the results. I do think the 8 km/h difference will be a considerable disadvantage to the RC drive. Some GPS units designed for training will give you the "ghost" pace of your last ride and maybe you could use this feature to keep the speed and such the same?
 
I didn't get around to doing the ride on Sunday.I had a choice between doing the test and going for cocktails with my wife and one of her girl friends (ex stripper :lol: ) As much as I love ebikes one has to get his priority's in order LOL

I am still trying to get all the gear together so I can collect all the data I need. I will pick Up the temp gauge today. I also downloaded another Iphone application called Dynolicious. It's basicly a Gforce meter accelerometer program. You put in the total weight of bike and rider then fix the phone to the bike. The program gives you 0-100kph times in 10kmh increments. it gives you max G under acceleration with graphs. Braking G's cornering G's, HP-KW.

I had a play this morning with it. I was able to pull 1.07G under brakes before the back wheel came off the ground. That's the same as a ford GT. Love the trike's braking with dual front disks and a very low centre of gravity. If I lay my seat back some more I could do even better
BrakingG.jpg




I will do no peddling acceleration tests for both motors.My total rider and bike weight is 97KG.I feel the best way to get around the wheel speed difference of the two motors is just to restrict them both to 50kmh with the CA.

Kurt
 
Kurt said:
I didn't get around to doing the ride on Sunday.I had a choice between doing the test and going for cocktails with my wife and one of her girl friends (ex striper :lol: ) As much as I love ebikes one has to get his priority's in order LOL
Click to expand...
What's a striper?
 
I knew that. Just pulling your legs.

Well, how was the 'striper'? You know, certain posts can be significantly enhanced with a picture.
 
Could have been someone that works with the department of transportation putting down road stripes.. good thing to clarify :mrgreen:

This is an interesting test sir. I really thought the RC drive system was going to be lighter, and that's quite disappointing to me. Sounds like the drivetrain bits definitely add the poundage.
 
The bafang is a light motor. You could build a much lighter RC drive system perhaps If you used a small RC motor and built a less sturdy reduction drive. My view is Matts reduction drives are already relatively light weight CNC machined aluminium component that have been striped down to the basics. I feel that even for a modest 2500w you wouldn't want go much less sturdy. There isn't much to be saved if you want to keep things strong and reliable. The 80-100 could be swapped for a smaller motor but you would be lucky to save 500g making it the same weight as the Bafang anyhow.

I am just charging the 60v lipo pack now, Buzzer just went off so its full. I will head out in a sec to do some 0-40kmh acceleration and G tests with the RC drive on 60v. I already have 0 - 40kph Data from the Bafang from this morning. Will post up soon.

Kurt.
 
Kurt said:
I am still trying to get all the gear together so I can collect all the data I need. I will pick Up the temp gauge today. I also downloaded another Iphone application called Dynolicious. It's basicly a Gforce meter accelerometer program. You put in the total weight of bike and rider then fix the phone to the bike. The program gives you 0-100kph times in 10kmh increments. it gives you max G under acceleration with graphs. Braking G's cornering G's, HP-KW.
Click to expand...

Excellent idea! Downloading an app for Android now going to see how many G's the ol 2 Speed cruiser can muster up :) Look forward to your results, give it a fist full damnitz! :mrgreen:

KiM

p.s Some pics of the "stripper" friend of the missus wouldn't go astray, "working" pictures if you catch ma drift :p
 
Stupid dam Fu**ing 9C ebike controllers and there auto activating cruise control :evil: Shorts and a t shirt and thongs didn't help though

Well I got some results from the RC motor . I also got to see what its like to run out of road with the cruise control locked on full throttle at 40mph :( I did I test run up the usual street then turned around to do a 2nd back the other way. This direction ends In a very sharp 90 deg left hand turn. I kept my throttle pegged until the last min then holy frock :shock: I tap the throttle again to reset cruise while trying to brake at the same time and just ran out of road.resorted to just fighting against the motor with the front Brakes in the last split second and few meters of road. Ended up in some ones driveway . Anyhow after I un-impaled my ankle from the front chain sprocket

From the day I got that controller and experienced the automatic activating cruse control (hold throttle in one position for more than 7 seconds) I knew it was a dangerous concept by design and was going to come and bite me one day.

stack.png





I limped the bike home and checked for damage. Small scratch on the rear trailer hitch mount at the rear and a couple of small scratches on the left mudguard that could be fixed with a black touch up brush.

Anyhow the results with no peddling
RC DRIVE 60V

0-10 kph 1.62 sec
0-20 kph 3.284 sec
0-30 kph 5.61sec
0-40 kph 8.58 sec

max G 0.47 G

BAFANG 60v

0-10 kph 1.03 sec
0-20 kph 2.27 sec
0-30 kph 4.50 sec
0-40 kph 8.94 sec

60 foot 3.90

max G 0.47 G

p.s Some pics of the "stripper" friend of the missus wouldn't go astray, "working" pictures if you catch ma drift :p
Click to expand...

She works as a architect now although we did have a cheeky party a few weeks back were things got interesting .

kurt
 
Wow, sorry to hear (and see) your problem. Glad you were no hurt worse!

One thing to make clear again (this was mentioned earlier in the thread), the RC drive has the capability of puting out much more power. This is a situation of purposely limiting the output of one system to get some data. The hub is being run at far higher percentage of its capability than the RC drive. Also, that is one heavy RC motor. I like to look at power capability per pound. If you are looking at efficiency, the same holds true. You need to look at a drive system that is designed around less power to really get a good idea of the potential efficiency. At 20mph, I see 12wh per mile on one RC bike and 18wh per mile on my 95 pound trike. Those are both overpowered RC systems. The efficiency could be even better if the systems were sized better for optimized efficiency.

Lastly, hub motors mess up an upright bike's handling much more so that a trike. So, handling on a trike is not as adversely affected by a hub as an upright bike is.

I do think hubs get a bad rap in this sub-forum, however. They serve a good purpose and fill a niche. They are cost effective, and much easier to install. It is kind of apples and oranges.

I like the idea of silent power, though. That is cool. 8)

Matt
 
Wow, sorry to hear (and see) your problem. Glad you were no hurt worse!
Click to expand...

Its all good no serious damage. I will be disabling that Auto CC though. Might start wearing some fingerless gloves to in the event of the odd spill.Some times you get a bit blaze about speed . I was coming down the hills on Sat and hit 89kmh-55mph on a twisty road might have to use the brakes more often now :?

video from sat where i hit 55mph coming down the hills at one point.
[youtube]WdbyQU5KFzI[/youtube]

I agree with all of what Matt just said.

I did mention at the start of the thread about it not being a power max test and the potential of the rc system is much greater. This is more I test for myself as riding the bikes with each motor there isn't much difference to me. So its to help me make a choice of what motor system I should run on my day to day electric trike.

At some point though you have to limit power for any system 2500w and 30 - 40mph is a reasonable amount for a day to day commuting and longer distance riding bike. 45A and 60v.Sure I could run 1/2 the size out runner motor But I am not sure how much different (or in favour of the rc motor) the results would be.

In the end what I expect to happen is i will keep the bafang for day to day and go silly with the rc motor but ony use it for fun - I bit like a weekend car :D

kurt
 
Hmmmm... so the RC motor you have is capable of a lot more power?...

I want the lightest yet most powerful thing out there, and after surveying all other options i arrived at the geared hub motor.
Please prove me wrong about my choice :)
 
Yes you could push a good 4500w into it with peeks of 10,000w. but if you were going to drive it around a lot under that kind of power as in sit at top speed for a long time and not just race or play around with bursts of power having fun. I would say 4500w would be a good max. Others know more than me about high powered set ups.

RC is at the top of the choices if you want light and powerful that's a fact.

light and modest power 2500w and under geared hub could be a good option to consider.

I think Free wheeling is the biggest advantage of both systems . Its just makes for a much better riding experience being able to power up hills and roll down the other side with no cogging slowing you down. Its amazing how even on flat ground you can give a burst of power and then just roll and peddle a little. Its a great way to get around at a good pace but efficiently.


kurt
 
+1 on free-wheeling ebikes. They are so different to ride than a DD hub.

I recently hooked up one of my drives to turn over a hub motor, and was shocked at the amount of power required to just turn the wheel around. Any wonder I feel like I am riding through sand when the battery quits.
 
Yeah, we can all agree on that. Free wheeling geared motors are what got me into electric bikes.. after seeing 16 pound hubs with notable drag on em from 2007-2009... i thought.. there has got to be a better way to do this.. and kinda avoided investing into an electric bike until i heard about geared motors in 2010.

I did have an eZip-trailz style setup for about a month and found that the lack of rotating mass on the wheel made it feel even more like a regular bicycle than my small MXUS geared motor & MAC motor. I think that is the best way to explain it.

I've always been interested in RC drive, but haven't been 'sold' on it just yet.
4500w out of ~10lb is pretty damn impressive but i'm looking for a better power to weight ratio ( if it even exists )
 
neptronix said:
Yeah, we can all agree on that. Free wheeling geared motors are what got me into electric bikes.. after seeing 16 pound hubs with notable drag on em from 2007-2009... i thought.. there has got to be a better way to do this.. and kinda avoided investing into an electric bike until i heard about geared motors in 2010.

I did have an eZip-trailz style setup for about a month and found that the lack of rotating mass on the wheel made it feel even more like a regular bicycle than my small MXUS geared motor & MAC motor. I think that is the best way to explain it.

I've always been interested in RC drive, but haven't been 'sold' on it just yet.
4500w out of ~10lb is pretty damn impressive but i'm looking for a better power to weight ratio ( if it even exists )
Click to expand...

How about 9,000 watts from 10 pounds? That is what I see from my 4 turn 3220 in my trike.

Matt
 
Excellent idea! Downloading an app for Android now going to see how many G's the ol 2 Speed cruiser can muster up :) Look forward to your results, give it a fist full damnitz! :mrgreen:
Click to expand...

Just reposting this section on new page

The Rc motor tends to take off really soft on 60v compared to on 40v I think its something to do with the ebike controller not sure why . But then at about 25 kmh it has a 2nd wind and pulls harder middle 3rd of its speed curve. Where the bafang gives a great strong launch and a real consistent pull for the 1st 1/3rd then its flattens out a lot before reaching max speed.

One interesting thing is that the max G's recorded for both motors was .47 G but the bafang can get that number even if you just accelerate to 15kmh then stop where the rc drive only gives me that pull from 30 - 40km

I guess peak G's are when you have peak torque system is pushing peak torque.

The results with no peddling
RC DRIVE 60V

0-10 kph 1.62 sec
0-20 kph 3.284 sec
0-30 kph 5.61sec
0-40 kph 8.58 sec

max G 0.47 G

BAFANG 60v

0-10 kph 1.03 sec
0-20 kph 2.27 sec
0-30 kph 4.50 sec
0-40 kph 8.94 sec

60 foot 3.90

max G 0.47 G
 
You must log in or register to reply here.

Similar threads

R
    • Like
Really good article comparing Bafang vs. Tongsheng vs. CYC
Replies
12
Views
10,867
999zip999
999zip999
Squilt
    • Like
4kW dropout mounted RC drive
Replies
10
Views
1,015
Squilt
Squilt
Squilt
    • Like
RC Drive Recumbent Trike Build
2
Replies
40
Views
3,379
Squilt
Squilt
R
    • Like
A critique of mid-drive riding recommendations (and hub drive criticisms)
Replies
15
Views
5,282
Bullfrog
B
N
Looking for advice on converting an Electra Townie
Replies
9
Views
1,107
999zip999
999zip999
Back
Top