Comparison between RC and ebike controllers?

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dirkdiggler

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I usually am in the skateboard/scooter forum, but since building my first ebikes I've been hanging out here in the mid-drive area. As there isn't much crossover between the two areas member wise, I am curious as to the major differences between the controllers used for ebikes and those for RC or scooters/skateboards. I don't know too much about the electronics, I'm learning slowly. My main question would be how is it that the controllers have such a huge difference in size and capabilities. The RC ESC's that we are using for skateboards top out at 24volts or 6s (You can go 12s for more money), but are able to handle around 150 amps. My controller on the BBS-02 maxes out at 25 amps, but uses 48 volts. The BBS-02 is much smaller than say a hub-drive controller, but is still huge compared to the RC ESC. From what I've read here (the non-hub motor drive forum), the RC ESCs are way over rated amperage wise - but in reality on my wattmeter using my eskateboard , the amperage seems to check out. I've pulled at least 80 amps on a 90a rated esc and it still functions fine. No smoke or fire. The ESC doesn't run hot at all using 1000 watts. Thats 24 volts times 50 amps. Same watts as the BBS-02. The RC ESC lacks some of the functionality of the ebike controllers, with brakes and wired throttle control. That is easily fixed with a servo tester though.

As space is limited on bikes as much as on a skateboard, why are not more people using the RC ESC on a bike setup?

Cost also seems to be a factor in the RC ESC favor with a 2000w bike controller being well over a hundred dollars and the RC ESC costing $50?

Any major disadvantage to using a 24v system with higher amps if the ESC can handle it?

Any help describing the differences in what's under the hood comparatively?
 
Well, a lot is in the packaging.
My Ebike controller is in a housing that is the size of a 250gm block of butter... but the actual controller inside is no bigger than a credit card and handles 1.5kW all day long ! ...and only cost $15 !
Not many folk have had success with RC controllers on Bikes..other than the high end Castle gear which seems to have some special software to prevent self combustion !
 
Below are just some observations based on my own experience and things I have read on this forum.

I believe the RC controllers are not ideal for smooth mid range power delivery compared to a standard ebike controller. My Lyen 12fet controller is currently programmed for about 3500 watts but it will happily creep along at 50 or 100 watts with good smooth control of the throttle. Power delivery is predictable and smooth all the way to full power. My understanding of RC controllers is that they want to dish out high power or no power and that low speed can burn them up. Sensored ebike controllers will also start from a dead stop very well. Again I have always heard that RC ESCs don't like to do this.

The relatively high RPM/Volt of RC motors does give you the benefit of using lower voltage batteries but then you need tons of amps. Building a battery system and wiring to provide 160-200amps requires heavier wiring and connectors that bring with them costs and complication. Amps seem to be harder on things than volts. The explosive power of a high KV RC setup seems like it can go wrong faster than spreading out the same power over a larger voltage range.

Common ebike controllers are very versitile
Right now I am running my Lyen 12FEt on a hub motor that has a KV about 10x less than the mid-drive motor I bought it for. I can easily switch it between the two bikes even though the motors are very different. A sensored E-bike controller is very customizable and provides good access to the circuit board for users to add features. They are very well documented on this forum so there is a huge knowledge base for customizing power levels and features.

It seems that RC ESCs are like the F1 racecars of the ebike world. Tons of power in a small package but with a very slim margin of error and a very narrow power band. Both types of controllers have strengths and weaknesses. It just depends on what the user wants and is willing to live with.
 
Thanks for the responses. My 1000 watt controller is more like a foot long and two inches high. Throttle response on the RC ESC actually isn't too bad with a skateboard. Maybe that is because of the lower voltage (6s) allowing a bigger spread. 48v might be more all or nothing on the RC ESC.

Hillhater -
What controller are you using and where did you buy it? There are some issues getting an ebike controller to work on a small RC motor, but if the size were better I would like to try it out. It would be good to use a higher voltage. $15 would be worth a try. I would still need a way to use a wireless throttle though.
 
I think that the kind of motor, the wheel diameter to drive, and the type and the time of the loads involved, are the first things to think about to find the key for this comparison......for sure, as mentioned, It's hard to get smooth starts and to manage slow speeds with RC controllers with a wheel diameter typical of a bike, I have never used them with an hubmotor, though, But, I have made some test with a sensored "E-bike" controller and an RC motor with an encoder, and It works fine.
 
Simple: An ebike controller is rated for continuous duty, whereas an RC controller rating is for a few seconds.

The difference is thermal mass and heat dissipating, which requires extensive heat sinking (size and weight penalty).

RC controllers also typically don't have current-limiting, which reduces their size and complexity.
 
There is also a problem with inductance and ripple current that I don't completely understand. The ESC "king of the hill" is the Castle Creations HV-160 with added output capacitors. It costs $250 retail, and the max volts are 50V, and you must still be cautious with extended high amps. $250 is a bitch when you fry one...

By comparison you can get a Lyen 12-FET 36V-100V, that will run 30A all day long and 45A temporary peak for $130

http://endless-sphere.com/forums/viewtopic.php?f=31&t=17683

The Turnigy 80-100 has been used successfully on several E-bike projects turning the rear wheel. The 80-100 and 80-85 have been successfully used driving the BB (which gives the motor the use of the bikes gears, less than 10-MPH in first gear).

The 63mm diameter motors have been working quite well for friction drive E-bikes (50mm is acceptable for flat land), using 60A-100A ESCs. (see link in my sig)

The stand-up scooters and power boards have used the 50mm-63mm diameter motors, I don't remember the amp-range of the ESCs, but since the tires are small, they accelerate quickly, and the amps drop off to cruise mode very soon (very short time under max amps)
 
I can get a RC ESC that will run 30a all day for $15. Although that is at 16v not 36v. I am still wondering which controller Hillhater is using. I grab that one fast. It just seems to me that the ebike controllers would find it important to keep the size down for easier placement on bikes. The BBS display units are the size if not larger than our Eboard controllers.
 
I too am curious what controller hillhater is using. I'll venture a guess it's a Hobbyking, 6S.

For just $10 more you can go to 90a. http://www.hobbyking.com/hobbyking/store/__7341__Hobbyking_SS_Series_90_100A_ESC.html
 
If someone wanted to really research this (comparing ebike controllers against RC ESCs) there was an in-depth explanation by Jeremy Harris during the "year of frying HV-160 ESCs".
 
I've been running RC ESCfor a few years now, but I know the limitations of it & don't ask too much. The bike is very difficult to ride if you're not used to it. The problem with RC stuff is that it is designed to turn a prop, not an haul 18 stone guy on fixed gearing.
I have a plan for (& have been workin on) a small board to utilise a hall throttle and an RC ESC to put together a "user friendly" package (note to self - I MUST remember to order some isabellenhutte shunts for it - it keeps popping the thick film ones....) The useful feature of it is that it asks the ESC for a voltage proportional to speed (+ a throttle dependent bit), therefore doesn't try too hard & lose synch at low speed. That part works exactly as planned. You do have to wire up a reed switch/spoke magnet thing to it (I used an old bike speedo one). Once I get it working I'll put a video up...
PS the shunt is there so I can make a power limit - should be good for both reliability and legality :)
 
Spinning,
I tried to find the thread on the HV 160, but nothing came up on a search. One major problem with ES is the search function. I'd really like to go through that. I know that Recumpense? is one of the few on here that uses RC motors on his bikes and I might have to go through some of his builds.

When I get a chance, I'll post a pic of the size difference between my 1000w ebike controller and a 100a HV airplane RC that I've used on a scooter and motorcycle with an 80-100 motor. I do agree the throttle response is one big problem on the RC ESC. I found that if I geared things lower, it helped keep it under control. This robbed the top end though. That so far has been my only complaint with it. That and the annoying screech when you let someone else ride it that is unfamiliar with how it works.

One of the reasons, besides the knowledge aspect, I had for this post was to see if it would be feasible or smart to use an ebike controller on an skateboard or a surfboard I'm hoping to build this summer. A big issue for an ebike controller is the throttle input. I do not want a wired throttle on an eboard. It might be possible on a surfboard, but the last thing I need is for the wire to get wrapped around the wheels at speed. I did just recently see this part while looking at the Astro motors website.
http://www.astroflight.com/electronics/speed-controls/rcpwm2v.html
rcpwm2v_1.jpg

The RCPWM2V is a device that converts a standard hobby RC signal (1-2ms pulse) into a proportional analog voltage (0-5V).

In many electronics applications the main processor is constantly busy and does not have the ability to address the time-sensitive PWM signal from an RC receiver immediately. This results in signal distortion or a sluggish response due to the extra filtering required. The RCPWM2V provides a simple solution by converting the signal into an analog signal. The main processor can then read the signal whenever it has time.

The input connector is a standard keyed male Futaba connector that plugs directly into the RC receiver.

The output connector is ordered so that it mimics a potentiometer (Ground, Signal, 5v).

The converter must be powered by the output side. It can pass 3A to the receiver, but the real current limit will depend on the supply from the controller.
Click to expand...

This might solve this issue if I understand it correctly. It should do the opposite of a servo tester, where you want to convert the analog signal to a PWM. Am I correct on this?

I contacted Lyen about wiring up a controller for me that would try and get the 5kw out of the 80-100 motor and he didn't have anything. If he did I am sure it wouldn't be very cost effective anyhow. With a HV RC ESC we can easily get into the 5kw area and cheaply at that.

Last issue with the RC ESC is the sensored/sensorless issue. On the eboards, it isn't much of a factor as most like to push start anyway. I would have figured that an ebike would be similar with a few pedal strokes to help the motor from cogging. That is however not what I've seen posted here. It wouldn't matter to me if I had to do this.

Would ebikers be happy with a 24v system if they could use 100 amps to get 2400 watts? Or is the thinking that a 70v system at 35 amps is better?
 
dirkdiggler said:
Would ebikers be happy with a 24v system if they could use 100 amps to get 2400 watts? Or is the thinking that a 70v system at 35 amps is better?
Click to expand...

For boards It's a different thing than for bikes. Here, except for the friction drives, the use of RC motors (from 6X mm) is usually at 12s.

I have an Astro 3220 with an HV160 at 12s. the system works great up to 26" wheels and 60Kph of speed.
Both the servo interface ( http://endless-sphere.com/forums/viewtopic.php?f=28&t=12196 ) and the Current throttle via CA ( http://endless-sphere.com/forums/viewtopic.php?f=28&t=29846&start=50#p440411 ) works great, the current throttle solve most of the slow speeds and surges problems with the throttle.
I think that a big enough motor is recommended for an RC non friction System, your 2400w could be the lower limit for a 20"+ wheel bike, unless you use a very high speed motor and a huge reduction factor using some sort of gearbox or planetary that probably is twice the motor weight...

Member, RonZ (3205+gerbox), ghwy (6X outrunner series), the 80-100 builds. the Astro 3210-20 belt drive builds (mostly Recumpence based), are all good and real world resources here to look at, for your topic....

Often, a torque limiter is used on very powerful RC setups, to prevent surges, wheelies, and mostly drivetrain disasters and Controller overcurrents....

I'm sure you know about AlienPowerSystem, Bruno is also a Member here, I'm not the right person to talk with about boards, but maybe it should be mentioned, I think that for boards, they offers some of the best solutions available....He also sells Motors and RC controllers specifically programmed for E-bikes, even for sensored use.

Cheers
 
Here's a pic to compare size of my 48v 1000w 20amp ebike controller and a 150a 24v 3600w? car esc that I use on my eboard.
esc.jpg

I didn't want to remove the HV ESC on my scooter to compare the 48v version. Its a similar size to the car esc. I'm not sure the ebike crowd knows how much smaller these are. As I also have the Bafang BBS-02 750w unit and have been following that thread - here is a picture of that controller. It's 48v 25a and 1200w.
gearampDamagedwire_zpsd2af1212.jpg

BBS01%20Controller2-500x500.jpg


I don't understand why these controllers are not smaller and that is one of my bigger questions.

I read through the latest Lightning Rods GNG kit post and he was saying that higher volts and lower amps decreases motor temperatures. I have read that before and is one of the reasons I believe the eboarders should look into using a higher voltage system. I think they maybe as stuck in their ways as the ebikers are. Problem is the 24v systems seem to work without many issues.

Speaking of Bruno and his ESC's. I was looking through the Flier ESC section (there may or may not be a relation to Bruno's ESCs, never found out how that worked) on aliexpress and came across their 22s(88v) 400amp car esc - which appears to be the same as the 22s 400amp ebike ESC. The car esc version is $100 shipped to the US. If the specs hold on 22s with 400a we are talking 35,200 watts. Is that even reasonably true? Especially for a $100 controller.

My next reading will be those threads Panurge. I've done the servo tester to use my HV ESC, but my issue is doing the reverse. Taking a PWM signal from an RC receiver and turning it into an analog signal to use an ebike controller. I even posted on that thread a year or so ago asking the same thing.
 
dirkdiggler said:
... I'm not sure the ebike crowd knows how much smaller these are....
Click to expand...
Yes we know, there are many more members that you can immagine here that use Castle or other tiny RC controllers.

Yes the Aliens controllers are basically the ones that you mention, they will mark and develop them as per your directions for massive orders, and you may also develop and program, that's what Bruno does, I think.
 
... I'm not sure the ebike crowd knows how much smaller these are....
Click to expand...
You are not raising anything new to the Ebike group.
Most of us have tried the RC ESC's ( the RC world is where many of us started) .. and most of us have the charred remains of those trials !
Without knowing the technical reasons why, the basic problem is that RC ESC's do not like part throttle use or high load (high amp) low speed start ups. In addition, unless a fully sensored motor & Controller set up is used, loss of sync is all too easy under acceleration.
Ebike motors are built for durability, reliability and torque,..intended for long periods of use,..hours , not minutes of an RC device. Ebikes need much more battery capacity than an RC Heli or car, so we can afford the weight of a high voltage , multi cell, pack which allows us to run lower currents for similar power levels with the resulting higher efficiencies
Most RC gear is designed for minimal weight ( for flight) and that restriction possibly results in compromises for durability, heat sinking, lower voltage, etc etc.
Ebikes are not at a loss for space and a 6 FET 1.5kW, controller is not exactly large.
http://endless-sphere.com/forums/viewtopic.php?f=31&t=19587
 
I was asked by PM to respond to this thread. So here is my take on it......

RC Systems can be plenty reliable for the long term. They can also be smooth and torquey. However, that takes specific components and very specific programming as well as specialized mechanical setup. Also, RC controllers can put out high power for long durations. But, that is dependant on component type and setup. Outrider USA winning pikes peak is good example of that fact.

That being said, the components that last are expensive and time consuming to setup. So it is a matter of what you are looking to achieve. For someone who wants the ultimate in light weight high performance, RC is the way to go, assuming they have the money and time to set it up. But, for inexpensive reliability where weight is not a big issue, a standard ebike system with big sensored controller may be a better choice.

There is an application for each system.

Matt
 
Matt,
Just to be clear, when you say "RC Systems can be plenty reliable for the long term.".. are you referring to using RC controllers with RC motors as a complete package. ?
The OP was asking why more people dont use smaller RC controllers with Ebike hub motors... or the recent mid mount systems.
..Which I believe that is a different "box of frogs" altogether to deal with.!
 
Hi All,

I am not an expert, but have been reading a lot recently to increase my understanding of these motors / controllers.

If I understand correctly:
RC motors in general do not have hall effect sensors, whereas most e-bike motors do have them.
Hall effect sensors, and the controllers that use their signals to control the timing of the current sent to the motor windings, are the main reason that e-bike motors can start smoothly from zero rpm and have strong torque at low motor speeds.
The lack of Hall effect sensors is the main reason that RC motors do not have such smooth startup, and do not have such good torque at low speeds.

To use an RC sensorless controller to drive an e-bike motor would lose this low speed performance, so most people would not want to do this.

Using an e-bike controller with a sensorless motor would also be a mismatch.

If this is not correct, or not complete information, I hope someone more knowledgeable than me will jump in and correct / expand it.

Regards,
Dave
 
In RC and in ebikes you can have nonsensored motors. The RC motor is best suited to an RC controller, picture the motor and the controller that each cost me less than $20 a few years ago, but there's work to do before you can use the controller with a throttle.

http://www.hobbyking.com/hobbyking/store/__18539__turnigy_l4255_500_brushless_motor_1100w_.html

http://www.ebay.com/itm/D9z-SkyWing-Brushless-80A-ESC-speed-controller-with-3A-5V-BEC-for-RC-Airplane-/141239707260

Plus the fraility of the controllers make one of these a nice touch. My theory was if the motor says it'll draw 50 amps, get an RC controller to the 80-100 range.

http://www.rcdude.com/servlet/the-2224/Castle-Creations-Cap-Pack/Detail

There were some great photos of bikes in flames a few years back, oh please don't put that controller under your seat.

A sensorless bike controller, such as can be found with kelly controllers or greentime or whomever, spares one the adapting a controller and is less risky. Of course it costs more.

As for your performance comments, that's a 'Your results will vary' thing.
 
sensorless e-bike controller work with most rc motors BUT most sensorless e-bike controllers only have a erpm limit of approx 10k so this is the limiting factor as most rc motors have a high volt per rev count. AFAIK most RC controllers have no form of current limiting so the startup from a sensorless controller can be very tricky and if you get it wrong the controller will pop, this is way rc controller like to have a running start if a high load is placed on it i.e slipper clutch, pedal a little before winding on the throttle or a push off before winding on the throttle. firmware in rc controllers also have differences and this can also effect how the controller starts the motor ( as the firmware is trying to decide which direction to spin the motor from a stop ). E-bike controller are a tad bigger but have much more function than rc controllers and are also are more serviceable ( and tend to be cheaper for the "real reliable" power capabilities and reliability than RC controllers) . Hi end RC controllers may have better firmware and higher spec components that help prevent massive current spikes damaging the controller at startup but the firmware may be just as good in a $20 rc controller even if the components are not of the higher spec. By using sensors, 100% of the guess work that a sensorless controller needs to do in the firmware is no longer a issue so then its just a matter of keeping the battery and phase currents under control, which most rc controllers do not do.

Edit:
Sensorless e-bike controllers are able to work better than sensorless rc controller because they have current monitoring.
 
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