Dual setup-Bafang/Cute

[1-track-mind]

I've tenatively settled on buying a Bafang 500 watt BPM for the rear with Cute Q-F-128 SX up front (either 350 or 500).
I'd love to hear your thoughts on this combination and also how to best finish out the conversion. Thanks.

 

[cell_man]

AFAIK Ananda do not rate any of their small 108 or 128 hub motors for more than 250W and I've been to their factory twice and discussed the motor specs extensively with their Sales people and R&D engineer. Just because you can overvolt them doesn't mean they are rated for that figure. I would personally never advertise a motor as rated higher than the manufacturers rating.... but then something I sold might not look as good on paper :wink: You should also be aware that the cost price of the 128 is about 25% less than the 108 I've used the 108 motor extensively and have a few 128 motors here but haven't tried them yet. The 108 motor has a very high reduction of circa 9:1 compared to a more typical approx 5:1 for pretty much every other hub motor I'm aware of. This means the motor spins much faster than other hub motors for a given rpm but IMO it also results in more drag when not under power. The 128 motor is a simpler gear AFAIK so should be better in that respect. Specs suggest the 108 motor has more torque but I've not personally tried them installed on a bike.

IMO the small motors are good within their limits but if pushed beyond those limits they seem to get inefficient. Swapping from a small Ananda motor (overvolts) to either a Climber or Puma motor and you will find that you can go everywhere a little faster with a more powerful feeling but still use about the same amount of capacity. Obviously this would be down to controller selection but for same Whrs/km I definitely felt a big difference between a Mac motor and an overvolts 108 Ananda 'Cute" motor and averagfe speed was about 2-3kph higher.

My advice would be to go with a strong single motor initially and see how you go with that rather than the complexity of a dual setup. If you went with a Mac motor you could choose to have a single steel gear for peace of mind, but is a bit noisier. The Climber is a nice motor, very smooth and quiet but not yet sure it's as strong or as efficient as the Puma. If you were happy to sacrifice a bit of speed but improve hill climbing ability you could always fit the motor into a smaller rim if the bike is not yet selected. I could ask about a lower speed winding for a Puma if you wanted. The standard is about 320RPM no load at 36V.

 

[HTB_Terry]

This is the first I heard that Ananda makes the so-called cute motor. So they have two models? I'd be interested in any test results, as well as dimensions and weight. I know Ananda makes their own controllers.

 

[cell_man]

The 108 and 128 motors are the spoke radius of the motors, ie 108mm and 128mm. The smallest version of the 108 motor, front with disk is 2.05kg. Will have to check the weights of the other variants, I have pretty much all of them here. They have many rpm variants of the 108 motor.

Ananda controllers are pretty good IMO. Compact, well built, look nice, perform well and are a good price. The 15A and 25A controllers are both very compact for controllers of that rating. The 35A controller is a bit of a lump but seems well up to the job and can run pretty high voltage AFAIK (not personally confirmed that though).

 

[The Stig]

The 108 motor has a very high reduction of circa 9:1 compared to a more typical approx 5:1 for pretty much every other hub motor I'm aware of. This means the motor spins much faster than other hub motors for a given rpm but IMO it also results in more drag when not under power.

Are you saying the cute motors don't freewheel(internally)?

The 108 and 128 motors are the spoke radius of the motors, ie 108mm and 128mm. The smallest version of the 108 motor, front with disk is 2.05kg. Will have to check the weights of the other variants, I have pretty much all of them here. They have many rpm variants of the 108 motor.

On the bms and battery website it says the lightest motor is 1.6kg, which is the true value? Whats the highest power you can run through the lightest hub motor?


I'm torn between going dual bafang or duel Cute motors... and if its duel cute motors what rpm variants and whats the highest power i can run them at reliably?

If anybody knows places to order front and rear bafangs or cute motors laced into 24" rims I would welcome your help!

Sry if I'm hi-jacking your thread, this is relevant though... i really like the idea of dual small gear motors too!

 

[cell_man]

The 108 motor has a very high reduction of circa 9:1 compared to a more typical approx 5:1 for pretty much every other hub motor I'm aware of. This means the motor spins much faster than other hub motors for a given rpm but IMO it also results in more drag when not under power.

Are you saying the cute motors don't freewheel(internally)?

The 108 and 128 motors are the spoke radius of the motors, ie 108mm and 128mm. The smallest version of the 108 motor, front with disk is 2.05kg. Will have to check the weights of the other variants, I have pretty much all of them here. They have many rpm variants of the 108 motor.

On the bms and battery website it says the lightest motor is 1.6kg, which is the true value? Whats the highest power you can run through the lightest hub motor?


I'm torn between going dual bafang or duel Cute motors... and if its duel cute motors what rpm variants and whats the highest power i can run them at reliably?

If anybody knows places to order front and rear bafangs or cute motors laced into 24" rims I would welcome your help!

Sry if I'm hi-jacking your thread, this is relevant though... i really like the idea of dual small gear motors too!

No they do freewheel internally but there is still drag on a frewwheeled motor. The think about the Cute 108 motor is that it uses a step down gear ratio of about 9:1 whereas all the other geared motor use about 5:1. In my experience there seemed to be more drag on the Cute than on the Puma or Bafang front motor. Regarding weight, I've got the QX85 108 motor, actually about 90mm wide which is the lightest they do as far as I know. This is for disk brake fitment. I've weighed this at 2.05kg. I haven't got to the bottom of the specs for this 1 even after visiting the Ananda factory but as far as I understand it is like a 180 or 200W motor at it's rated voltage, but I was told that running a 24V motor at 36V and limiting current t say 15A is. The wider 108 motor uses a different gear arrangement but the same 9:1 ratio. My mate Lunchy posted a few pics of the internals of the Cute motors some time back :wink:

Ananda offer many rpm variants. I have a 108, QX85 front, 250rpm 24V front, some QX100 24V rears speed unknown, as well as 36V fronts, speed about 200rpm. The Bafangs are maybe a slightly stronger and nicer motor but also more pricey and much heavier and bigger. The Climber is not that much heavier than the small Bafangs and quite a bit stronger. Bafang don't seem to offer the same speed options as Ananda but if you order enough with them they'll make whatever you want. Might well be placing a Bafang order next week, last opportunity before Chinese New Year.

Also have a few of the Ananda 128 motors which i've not yet tried which are roughly Bafang size and weight. Will try to get a double cute bike ready soon. I've got the bikes, motor etc, just no time to put it together. I've got a few motors unused here and could maybe arrange the rim but good quality 24 rim and a the right length spokes might be a bit of a PITA to find. BTW Ananda are not taking any orders till 22nd Feb with 3 weeks lead time, due to Chinese New Year holiday so if you order a non stock item from somewhere it might take rather a long time to arrive, so be warned....

 

[full-throttle]

The Climber is a nice motor, very smooth and quiet but not yet sure it's as strong or as efficient as the Puma.

Their max efficiency on paper is roughly the same: 77.9% for MAC (@36V 299rpm) vs 78% for BPM 350W (@ 36V 240rpm), but no-load bench test results are very different - while BPM 350W draws 1.5A @ 52V (wot), MAC draws more than triple. MAC spins faster.

 

[cell_man]

The Climber is a nice motor, very smooth and quiet but not yet sure it's as strong or as efficient as the Puma.

Their max efficiency on paper is roughly the same: 77.9% for MAC (@36V 299rpm) vs 78% for BPM 350W (@ 36V 240rpm), but no-load bench test results are very different - while BPM 350W draws 1.5A @ 52V (wot), MAC draws more than triple. MAC spins faster.

Hi Dmitrii,

I think you're comparing the 500W Mac which is considered to be a very conservatively rated 500W and the 350W Puma. The Mac you have is also likely fitted with a single steel wheel which may increase the drag a little. I believe the Mac also has double the poles of the Climber and as you stated is a higher rpm motor. Together these things could effect the no load current draw but how important is the no load current draw? I know the Mac will happily run at 48V and beyond. Bafang are reluctant to rate any of the climbers to 48V. The 350W climber you are running at 48V has the same gears as the 500W climber and all climbers from 250-500W contain the same gears. The 350 BPM will therefore be putting out less power at 48V than the 500 BPM and is less likely to cause gear issues than a 500 BPM. Granted Bafang do have very high standards with regards to acceptable life cycle and I've seen the test benches they use for testing their motors which put them under various continuous uses. I believe they must exceed 2000hrs useage , stop start etc to be acceptable so their standards are very high.

I don't have any axe to grind against either brands. I'm gonna be placing an order with Bafang maybe next week and placed an order with Mac some time back and am expecting the delivery any time soon. Also have a few higher rpm Mac motors, circa 400rpm plus at 36V for a double motor setup The 320rpm is seriously rpm limited at 48V in a double motor installation.

 

[full-throttle]

No worries Paul,

I'm comparing MAC 500W (M12060, 36V, 365rpm no-load,all plastic gears) and BPM 350W (36V, 260rpm no-load).

Both running at 52V with no load on the bench.

how important is the no load current draw?

Well, put it this way: on the flat without pedaling MAC will consume an extra 175W.

Apologies 1-track-mind for stealing your thread, I like your idea btw. How are you planning of solving dual throttle/controller issue??

 

[The Stig]

I think the simple solution to that is to just wire two similar controllers to one throttle. I know it's possible but have no experience with it.

 

[cell_man]

No worries Paul,

I'm comparing MAC 500W (M12060, 36V, 365rpm no-load,all plastic gears) and BPM 350W (36V, 260rpm no-load).

Both running at 52V with no load on the bench.

how important is the no load current draw?

Well, put it this way: on the flat without pedaling MAC will consume an extra 175W.

Apologies 1-track-mind for stealing your thread, I like your idea btw. How are you planning of solving dual throttle/controller issue??

Sorry but I still do not think that is a fair comparison. Firstly the gears have drag that increases in a non linear fashion, AFAIK the losses increase exponentially so the additional RPM will result in much more losses because of the higher RPM and not just differences in the gears. These motors are not only different rpm but also different power ratings so the different coil impedance will also effect the difference in the no load current draw. I do not think that the assumption you've made above holds true if a comparison were made at a given speed that both these motors can sustain at a constant cruise. I'm sure in this scenario the differences are marginal. I have personally tried the MAC and found it to be much more efficient than using a smaller motor. Using the same Whrs/km I was maintaining an average speed at least about 2-3kph higher if not more and was accelerating much better. Both the Mac and Bafang climber are very efficient motors and I have test results which show the Mac gets more efficient at higher voltages and is over 84% efficient between 326-363rpm at 48V and peaks at 85.4% efficiency at 349rpm.

 

[northernmike]

removed.