Bafang 750w Motor Upgrade

[cuekwe Jones]

Hi folks, couple of quick questions (for those who might know) about the Bolton/EBW Bafang "true" 750w motor upgrade.

(1) I have read/heard from multiple online sources that the upgraded 750w motor provides additional torque over the stock Rad motors, but not increased speed (without a motor controller upgrade). Rad Power Bikes (RPB) specifies the torque of their motors at 80nm, yet which is the same advertised spec for the Bolton upgraded motor (I assume also the EBW motor, though EBW doesn't specify). So question #1: If both the stock RPB motor and upgraded motors are rated at the same torque, how is the latter an improvement over the former? Or does the benefit of the upgraded motor derive solely from (or in combination with) the upgraded controller and display? (I am aware that the upgraded motor will only work with the upgraded controller/display).

(2) I notice that the male motor connector coming from my stock RPB motor has 3 main round power pins in the center of the connector, but also 7 flat outer pins/lugs around the inside perimeter of the connector (I assume control pins) that appear to be missing from the mating end of the upgraded motor connector (or near as I can tell from online photos). So question #2: Is there any functionality sacrificed with the upgraded motors in consequence of not being identical to the stock connector? Or, am I perhaps mistaken that there is any difference at all?

Thanks in advance for any help with these questions.

 

[Kyogiro]

Hi,

1) Can't say about the stock controller but with the upgraded controller, torque and top speed are better with the true 750W. I upgraded the controller first because I received before the motor. I don't have detailed numbers like exact torque. With my usage :

upgraded controller + stock motor = sustainable top speed ~ 40 km/h (25 mph)
upgraded controller + 750W motor = sustainable top speed ~ 45 km/h (28 mph)

2) the upgraded controller from either source is 100% plug and play, same connectors all the way.

 

[Ccount]

Hi folks, couple of quick questions (for those who might know) about the Bolton/EBW Bafang "true" 750w motor upgrade.

(1) I have read/heard from multiple online sources that the upgraded 750w motor provides additional torque over the stock Rad motors, but not increased speed (without a motor controller upgrade). Rad Power Bikes (RPB) specifies the torque of their motors at 80nm, yet which is the same advertised spec for the Bolton upgraded motor (I assume also the EBW motor, though EBW doesn't specify). So question #1: If both the stock RPB motor and upgraded motors are rated at the same torque, how is the latter an improvement over the former? Or does the benefit of the upgraded motor derive solely from (or in combination with) the upgraded controller and display? (I am aware that the upgraded motor will only work with the upgraded controller/display).

(2) I notice that the male motor connector coming from my stock RPB motor has 3 main round power pins in the center of the connector, but also 7 flat outer pins/lugs around the inside perimeter of the connector (I assume control pins) that appear to be missing from the mating end of the upgraded motor connector (or near as I can tell from online photos). So question #2: Is there any functionality sacrificed with the upgraded motors in consequence of not being identical to the stock connector? Or, am I perhaps mistaken that there is any difference at all?

Thanks in advance for any help with these questions.

Keep in mind that Rad advertises the motor they provide as being 750w. It is not. Therefore, I would be dubious about their torque ratings as well...

 

[cuekwe Jones]

Hi,

1) Can't say about the stock controller but with the upgraded controller, torque and top speed are better with the true 750W. I upgraded the controller first because I received before the motor. I don't have detailed numbers like exact torque. With my usage :

upgraded controller + stock motor = sustainable top speed ~ 40 km/h (25 mph)
upgraded controller + 750W motor = sustainable top speed ~ 45 km/h (28 mph)

2) the upgraded controller from either source is 100% plug and play, same connectors all the way.

Thanks. Didn't really answer either of my questions fully (beyond what I already know). I know, for example, that the upgraded motor connector work "plug-and-play" with the stock motor controller in the sense of mating with the stock connector and delivering power to the motor. My question, more specifically, is whether any functionality is lost (e.g., display functions) because, again, the two connector pinouts do not appear to be identical? But again thanks all the same for your reply.

 

[cuekwe Jones]

Keep in mind that Rad advertises the motor they provide as being 750w. It is not. Therefore, I would be dubious about their torque ratings as well...

Thanks. This thought had definitely occurred to me. But I don't think ebike manufacturers have the same kind of wiggle room to fudge the torque spec in the same way as the power spec (e.g., by rounding up instead of down). Though I may be mistaken about this.

 

[AHicks]

#1 is about the fact RAD has taken it upon themselves to be "creative" with the wattage rating of the motors they are using. Most accept that as a fact. So I would ask then, if we can't trust them to provide the correct wattage rating, why should be believe anything else they have to say about that motor? The bottom line is this. It's nearly impossible to prove any type of advertised rating numbers, and clearly, we see that RAD is capitalizing on this fact (among others). It's also what makes it difficult or impossible for law enforcement to force any issues that might bring a motors ratings into question.....

#2 I think you're looking at a bad picture regarding not seeing the outer row of contacts. I think that in addition to the 3 primary (phase) wires, 2 more smaller wires will be necessary, a positive and a negative, for the motor to run, even in "unsensored" mode - without the hall sensors. I could be wrong on that though.

Also, you mentioned in passing that the "upgrade" motor won't run on the stock controller. I'm pretty sure it would run fine - but it would be pretty easy for any kind of horseplay to overheat that controller, making the wisdom of doing that a questionable move.

 

[cuekwe Jones]

#1 is about the fact RAD has taken it upon themselves to be "creative" with the wattage rating of the motors they are using. Most accept that as a fact. So I would ask then, if we can't trust them to provide the correct wattage rating, why should be believe anything else they have to say about that motor? The bottom line is this. It's nearly impossible to prove any type of advertised rating numbers, and clearly, we see that RAD is capitalizing on this fact (among others). It's also what makes it difficult or impossible for law enforcement to force any issues that might bring a motors ratings into question.....

#2 I think you're looking at a bad picture regarding not seeing the outer row of contacts. I think that in addition to the 3 primary (phase) wires, 2 more smaller wires will be necessary, a positive and a negative, for the motor to run, even in "unsensored" mode - without the hall sensors. I could be wrong on that though.

Also, you mentioned in passing that the "upgrade" motor won't run on the stock controller. I'm pretty sure it would run fine - but it would be pretty easy for any kind of horseplay to overheat that controller, making the wisdom of doing that a questionable move.

Thanks. I am aware of the disparity in the advertised power ratings throughout the ebkike industry, the reasons why, and in particular how RPB has inflated its number (strictly speaking). But this does not answer my question about the relative comparison of torque between the stock RPB motors and the upgraded Bafang "true" 750w motors.

As for my question #2, I am again seeking to confirm (with a relative high degree of certainty) whether or not the Bolton/EBW motor connectors have that outer set of contacts (and are fully functional). I could of course just direct these questions to those suppliers, but I figured someone on this forum would know for sure.

 

[AHicks]

You want proof of the difference in torque Rad vs. aftermarket REAL 750w motor?
Look at the opening picture here:

You want concrete, written is stone answers, call the suppliers - or do some more research on your own so you can find a picture of the connector that more clearly shows the outer row of contacts.

 

[RangerDave]

Sorry I don’t have specific answers to your 2 questions, but here is a YT video by CitizenCycle that shows the various improvements to a Rad Rover at several stages (upgraded motor, controller and battery). It may provide you with some info you are seeking. Performance comparisons begin at about the 4:25 mark.

Regards - RangerDave

 

[cuekwe Jones]

Why ask questions here when you won't believe the answers? You want proof of the difference in torque Rad vs. aftermarket REAL 750w motor?

I did not ask for proof that the two motors differ with respect to torque, or even whether they do. If you read my first post carefully, I asked (in effect) why both motors are spec'd for torque at 80nm when one (the upgraded motor) reportedly has more torque than the other? If true, then one of these vendors -- either RPB or Bolton (or I suppose possibly both) -- is advertising an incorrect torque rating. I am simply trying to determine who, if either, has the correct spec, and ideally the reason for this discrepancy?

For instance, I don't know how they calculate torque but this seemingly cannot be a simple function of power (in watts), battery voltage, and/or controller current, because (as I understand) none of these parameters are fixed -- you can use the Bolton motor with a either a 48V or 52V battery, and/or, say, a 30A versus 35A controller. But do varying these parameters change the torque? If so, then why specify the torque at 80nm? Of course there must be answers to these questions, which is again what I am trying to discern.

Btw, this is not the first time you've gotten snotty with me and without cause. Why the adversarial attitude? Folks come here for help/information, not lectures. If you don't have the patience to deal with us mere mortals then maybe you're in the wrong business.

 

[cuekwe Jones]

Sorry I don’t have specific answers to your 2 questions, but here is a YT video by CitizenCycle that shows the various improvements to a Rad Rover at several stages (upgraded motor, controller and battery). It may provide you with some info you are seeking. Performance comparisons begin at about the 4:25 mark.

Thanks Dave. I've watched all of Citizen's videos multiple times, yet which don't answer my specific questions (or near as I can tell).

 

[Kyogiro]

I did not ask for proof that the two motors differ with respect to torque, or even whether they do. If you read my first post carefully, I asked (in effect) why both motors are spec'd for torque at 80nm when one (the upgraded motor) reportedly has more torque than the other? If true, then one of these vendors -- either RPB or Bolton (or I suppose possibly both) -- is advertising an incorrect torque rating. I am simply trying to determine who, if either, has the correct spec, and ideally the reason for this discrepancy?

Marketing, legislation, I mean pick your choice. Won't be the first time and certainly not the last and this is anything but a shocker.

For Canada and Europe, my guess would be legislation. In Canada, Rad officially uses 500 W hub motor and in Europe, 250 W. Both conveniently allows Rad bikes to register as regular bicycle without the hassle of a Moped (licence plate, insurance, not allowed to be on bicycle lanes, specific helmet, etc...).

In the USA, my guess would be marketing. 750W (and the corresponding torque) sounds better than 500/350/250 W. Can't prove Rad's intentions though, just speculation.

I suspect Rad to uses the same 350W in every part of the world (cheaper and easier to source). Again, no "definitive proof" but the stock motor across continents look pretty similar. But if one day a stock USA Rover would be in Europe, I wouldn't mind comparing our 2 stocks motors even though there's not really a big point doing that.


What we know : the 750W true motor offers more torque and power (multiple videos on YouTube and those videos could serve as measurements instead of relying on feelings + direct feedbacks of users on this forum).
Nobody has lost a perceivable function over the upgraded 35A controller, on the contrary, the new controller has unlocked more functions.

Other than those informations that you already know, you're gonna have to address those questions to Rad (doubt they're gonna be very clear about their motor) and the suppliers of the 35A controller. But I feel like you're looking for something that isn't there, good luck though in your research.

 

[cuekwe Jones]

What we know : the 750W true motor offers more torque and power (multiple videos on YouTube and those videos could serve as measurements instead of relying on feelings + direct feedbacks of users on this forum).
Nobody has lost a perceivable function over the upgraded 35A controller, on the contrary, the new controller has unlocked more functions.

Other than those informations that you already know, you're gonna have to address those questions to Rad (doubt they're gonna be very clear about their motor) and the suppliers of the 35A controller. But I feel like you're looking for something that isn't there, good luck though in your research.

Thanks. Micah Toll of Electrek, who I trust to be knowledgeable on such matters, created an excellent video explaining in detail how and why the industry inconsistently rates motor power (in watts), and he specifically addresses (and justly questions) RPB's rating. This much I understand -- that the upgraded motor (the "true" 750w Bafang motor) -- indisputably has more power than the stock Rad motors. What I still don't know with any certainty, because unfortunately I am not an electro-mechanical engineer, is whether more power necessarily translates to more torque. Owner reports suggest that it does. However advertised spec's suggest that it does not; both motors are advertised as having 80 Newton-meters of torque. Hence my original question -- I just don't know how I could state it any more plainly than this.

But all that being said, I don't want to beat this horse to death. At this point I will just accept owner reports of significantly greater torque despite advertised spec's suggesting no difference (or anyhow not without additional modifications, such as the upgraded 35A controller, higher voltage/watt-hour battery, or whatever else???).

 

[Kyogiro]

Look at the videos on YouTube and, let's say, how fast they achieve 20 mph. The acceleration would be a much better indicator of the torque than top speed. The better acceleration is quite measurable since a bunch of guys on YouTube takes the exact same route, it is easy to spot if one motor would reach a certain point (close enough, not far away since top speed differs) faster than the other.

 

[cuekwe Jones]

Look at the videos on YouTube and, let's say, how fast they achieve 20 mph. The acceleration would be a much better indicator of the torque than top speed. The better acceleration is quite measurable since a bunch of guys on YouTube takes the exact same route, it is easy to spot if one motor would reach a certain point (close enough, not far away since top speed differs) faster than the other.

Just to be clear, my own personal concern/goal is not higher speed. What I want, primarily, is better hill climbing power. And I know that higher torque translates to better climbing power. The issue with my RadRunner is that above a certain gradient -- I don't know the exact figure (probably around 12-14%) -- the torque pretty much gives out, given my weight (~200 lbs). But before shelling out ~$500 for a new motor and controller, I was merely looking for some expert reassurance that I would in fact realize a significant increase in torque, and perhaps whether the controller upgrade alone will achieve this goal or that I also need to upgrade the motor itself.

My armchair reasoning is this: If the controller by itself does the trick, then why bother upgrading the motor? To repeat, there are doubtlessly good answers to this question. But if I already knew the answers I wouldn't be wasting other people's time.

 

[Kyogiro]

Basically, Volt = top speed
Ampere = torque

25A controller delivers fewer max A than the 35A, thus improving torque.

 

[cuekwe Jones]

Basically, Volt = top speed
Ampere = torque

25A controller delivers fewer max A than the 35A, thus improving torque.

This is a potentially helpful clarification. However I have been under the impression that battery voltage (if that's what you are referring to) basically translates to greater range (in amp-hours) -- e.g., that a 52V battery will normally last longer than a 48V battery (at a fixed current and motor output), whereas higher speed derives from the higher current output (amperage) from the controller. It's been a very long time since I studied any of this, but I vaguely recall torque being related to moments of inertia, arm length, and so forth; for example, that wheel diameter plays a factor.

But anyway, it sounds like you are saying that the upgraded motor might be superfluous to my needs so long as I get the 35A controller?

 

[Kyogiro]

It is just a tad bit more complicated than that. For mobile devices, you will see the capacity of the battery written in Ah (Ampere hour) but it is incomplete. The capacity of battery should be written in

Volt x Ampere x hour = VAh = Wh, that is why you would often see the consumption of an ebike's battery written in Wh/mile or Wh/km
and
Volt x Ampere = Watt

So higher V or A will give you a higher battery capacity. The ability to draw more A will increase torque and drain the battery faster.

As you drain the battery, its capacity diminishes which is the voltage, thus top speed will decrease as well.
As you allow more current (A) to go to your motor from the battery, you increase your torque.

If the higher torque offered by the 35 A controller alone would be enough for your usage, I wouldn't know.

 

[cuekwe Jones]

It is just a tad bit more complicated than that. For mobile devices, you will see the capacity of the battery written in Ah (Ampere hour) but it is incomplete. The capacity of battery should be written in

Volt x Ampere x hour = VAh = Wh, that is why you would often see the consumption of an ebike's battery written in Wh/mile or Wh/km
and
Volt x Ampere = Watt

So higher V or A will give you a higher battery capacity. The ability to draw more A will increase torque and drain the battery faster.

As you drain the battery, its capacity diminishes which is the voltage, thus top speed will decrease as well.
As you allow more current (A) to go to your motor from the battery, you increase your torque.

If the higher torque offered by the 35 A controller alone would be enough for your usage, I wouldn't know.

Excellent, thanks again. And I meant to say above with respect to battery capacity watt-hours, not amp-hours.

 

[WarehouseGuy]

This is a potentially helpful clarification. However I have been under the impression that battery voltage (if that's what you are referring to) basically translates to greater range (in amp-hours) -- e.g., that a 52V battery will normally last longer than a 48V battery (at a fixed current and motor output), whereas higher speed derives from the higher current output (amperage) from the controller. It's been a very long time since I studied any of this, but I vaguely recall torque being related to moments of inertia, arm length, and so forth; for example, that wheel diameter plays a factor.

But anyway, it sounds like you are saying that the upgraded motor might be superfluous to my needs so long as I get the 35A controller?

YES, probably might be superfluous! ;-) Please, set all your other impressions aside. ;-)
Math, it's always just math. An increase in voltage (48V-52V) is not necessarily an increase in Amp hours (Battery Capacity).
I agree with ... As posted above:
Basically, Volt = top speed (Higher Voltage = Increased TOP SPEED) 48V (54.6V fully charged) to 52V, not so much.
Ampere = torque (More TORQUE = EASIER CLIMBING, and gets to top speed QUICKER) What YOU WANTED!
I will add: Amp Hours = RANGE (How long your battery lasts ... capacity)

IMHO: Increasing your controller amperage will reduce your range, but produce greater torque, with a very slight increase in top speed.
If you can live with the decreased range of the 35 Amp controller and your current battery, great. In order to increase your range you will need a battery with more Amp Hours. 48V or 52V, pick one.

A Formula for you: Volts(Battery) X Amps (Controller) (not amp hours) = Watts

Example: My Sondors MXS - 48Volt (battery) X 25 Amp (Controller) = 1200 Watts (power delivered to the motor) At 100% Full throttle or PAS set to100% Here's some What If Numbers:
52 Volts X 25 Amps = 1300 Watts
48 Volts X 35 Amps = 1680 Watts
52 Volts X 35 Amps = 1820 Watts
Simply plug your numbers in the above formula to see the results of any planned changes or current settings.

You have many choices available to you , depending on your preferences. I would probably NOT upgrade the motor or battery until they die. To increase the range of my Sondors (750 Watt) MXS, I run a dual/parallel battery setup. Each is 48Vx17.5 Ah. I run one battery until it's nearly depleted, then engage the second battery. Twice the fun. For easier hill climbing (I pedal), I swapped out my factory 48T chainring for a 42T and will soon be changing my 14T-28T freewheel for an aftermarket DNP 11T-34T one. That should let me cover almost any situation I come across. Good luck.