I don't know if anyone has explained this yet, but the problem is magnetic induction in one moter feeding inverse flow into the other. It is creating an oscillation back and forth between the two. As one spins faster than the other it acts as a generator to the other. This is demonstrated when you turn one by hand the other rotates in the opposite direction.this means the moters are constantly fighting each other. If you wish to run two on the same controller you could try either run them in series while doubling your voltage or add some capable diodes to prevent backflow. I would recommend two moter controllers however. One side effect of this is the dynamic breaking, so coasting would be an issue.
I dont think you know how these works yes they dont work together under load I tried but you cant connect 3 phase in series or ad a diode to a ac motor
Clearly people don't know the controller for brushless (AC) uses back feed or hall sensors to know how the motor is positioned. You can't hook 2 together and have the 3 phase timing correct for both. Now brushed (DC) motors you can hook up in parallel and it will work.
It is possible but the controller needs to be modified to stop the feedback from one motor into the other. Open the controller and double every output stage (at least you'll need another 6 N-Channel FETs plus 6 times the SOAR circuit) That way you give your controller a second Motor Output that doesn't feed back.
The wise thing to do would be to use two speed controllers and two motors connected to a single throttle source. That's how quad copters are built. Each motor has its own speed controller, and the speed controllers are synchronized when you calibrate throttle position.
blise and chris you are both right but its grossly under powered either way that's a 250w controller and (2) 250w motors in parallel whcih makes them running about 125w a piece. also by adding the other motor you are adding resistance (ohms) to the inner workings of the controller. you've effectively doubled the work that the controller has to do to put out that same 250w. it might work but not for long ESPECIALLY under load.
By the looks of it, it seems to make more sense just to add a second speed controller ( or one designed for dual motor setups.) Either way, it's still a good experiment and I'm glad you took the time to figure it out so the rest of us don't have to
Your assertion at 9:29 is very correct. I was very glad to see that you do not recommend doing this. There are other reasons why this is real bad in real word usage. Watch what happens when you connect the 2 wheels to a common surface where the cant readily slip between each other. Or you can try using a chain or cog belt between them. In other words locking them to try to spin alike. You will burn things because the motors are never identical. I did these tests years ago with help from Neu Motors and Castle Creations. The noise you are hearing is a harmonic vibration because of the difference between the motors. Best way to do this cheap is use a common feed to separate controllers. But you can still get fighting between the 2 motor systems because of motor differences. Now I had great results using the hall effect switches as regulators to make the separate motors spin at the same speed and stay synced. But that took more processing from outside the controllers. Now this could be accomplished with the use of Raspberry Pi or the like.
these motors have one way clutches, so one will drive and not the other until the tires slip. if load increases and causes a speed decrease, both motors speed decrea, so only the wheel with the bigger dia tire drives.
Will George Interesting. So you lose drive if one wheel out speeds the other but you continue to drain power from your battery. That is a model of inefficient behavior in an electric model. Also the motors are still in essence still fighting each other in my book. The drive sides will always be hitting upon the other. I think it far better to control one then use the Hall effect switch to trigger control of the other. Then the motors will be synchronized. At least that’s how I see it. Maybe I should pull out some parts and revisit this issue.
This procedure has been done by electric kick scooter with a dual motor like the Dualtron and others. Mine has a dual drive motor but use only one controller with the same kind of configuration as shown in this video.
Nice. I’ve actually did the same thing but instead of one controller I did it with two 48v controllers and 2x 1000 watt hub motors. and rewired the controller to work with one throttle. My goal was for more torque but also gained a little bit of more speed from 28 mph to 34 mph
@@vladimirryder5195 yea I did use the same battery for both controllers I also made it work with two separate batteries for each controller as well but I prefer the single battery instead.
@@tsmithurst yea I did use the same battery for both controllers I also made it work with two separate batteries for each controller as well but I prefer the single battery instead.
Running both like this will be fine but they will be noisier under load than normal as no hall effect sensors are used. Controllers are cheap, so it would make sense to use 2 controllers, then you can use the hall effect sensors. They can both be connected to the same throttle without issue.
I would think there would be miscommunication with the hall effect sensors. They have to be able to tell the motor where the windings are but if both motors are in different positions the controller won't send a proper signal to the motors.
I suspect this’d be a lot worse on an actual bike. In this setup, the motors are free to ‘align’ their phases, as they’re spinning in air; on a bike, they’d be forced to travel the same speed (staying out of phase) or, even worse, to travel at different speeds when cornering.
How about mounting it to a common axle? I'm thinking of placing two direct drive motors from a washing machine (which are not the same as these but also BLDC) on the same axle and connected to the rear wheel via a chain. My theory is that if I place hall sensor wires to one of the motors and align them properly in phase they would turn just fine. I'd use a 2kw controller in that case.
I know this video is from four years ago. In that time period commercial e-bikes with dual hub motors have come to market. I have one. Mine is an EMX-Xtreme 500 from Fabulous Ebikes that has two 500w hub motors running on a single KT controller. KT (Kunteng) sell a controller designed to support two motors. In use I'm finding the set-up works really well. With each motor having 80Nm of torque the bike has relatively great acceleration and hill-climbing. On level terrain it appears both motors just share the load put on them by the pedal-assist settings. I can switch on or off the front motor while riding. On level terrain, switching on the second motor does not double the amperage draw. It stays practically the same whether one motor or two. On the EMX-Xtreme 500 the bike comes standard with a 48v 30Ah (1.440Wh) battery. With that I've had real world ranges per charge of 110.4 miles to 156.9 miles. Fabulous Ebikes also sell models with 60v 23.4Ah (1,400Ah) battery and a pair of 750w hub motors, again with a single-controller solution.
Very nice sir, now you kmow im not lying.. We used 1kw controller on 2 500watts hub motor. I think this setup will burn the controller if the 2 motor have load. Thank you sir
@@BORNFREEININTHACD Difficult setup! Though probably not what you want to hear the easiest, troublefree setup would be a single motor/controller front wheel drive. Spitballing here but option two would be a two controllers/two motors probable equipped with hall effect position sensors for both rear wheels. Would need some circuit/microcontroller to act as an electronic "differential" to keep both motors synchronized. Just a semi-educated guess. I have more then 15yrs of BLDC motor/controller experience but not in this application.
@@barthchris1 I have a dual motor electric kick scooter and I looked inside its only one controller the same configuration as this video. Its been using by the E scooter manufacturer with a dual motor.
Sry if this question has already been answered ... with having only the stator windings in parallel and only one motor having the hall sensors connected to the controller, what are the result in Power consumption? My thoughts ... having dual conflicting input signals is probably having an effect on the controller output. With only one unit giving feedback to the controller, the output frequency will be equal to both units, as the second is purely slave unit with the results being a closer to a doubling of the overall current draw. Now if that slave is proportionally under more load, what is the outcome?
with 2 controllers you still splice in both hall effect sensors for one controll, this is all you had to do and they would sync. In addition they are both running the same direction, one side if used on a trike would require you to swap any 2 wires on the motor going backwards around.
Induction resistance and feed back. The pluses have a feed back and you're feeding them to the other motor, there is a build up which amounts to the "losses" you saw which is around 50% of the power (cycle). Put on diodes and a load cap. Then it will work fine. Isn't the controller and motors miss matched?
Brushless motors cannot be connected in parallel or in series. That would only work if the motors were mechanically connected to each other in exactly the right position and the Hall sensors were only connected to one motor. Exactly this is not possible with our intended use. Motors with brushes, on the other hand, can easily be connected in parallel or in series.
This was very helpful info since I own a HUNTER QUAD electric scooter. This scooter has 2 motors on the front wheel and 2 in the rear wheel. Each motor rated at 72V 3500w for a total of 14000 watts but it uses 4 X 45Amp controllers. I am currently modifying it with 2 controllers, 1 Sabvoton 72200 for the front and 1 for the rear with a shared thumb throttle. Here's a the video of the scooter and I am the person you'll see speaking on the video. th-cam.com/video/aBQfs0V3wos/w-d-xo.html
The motors are out phase. Probably 30-40% of the power when both motors are running is canceling out on the wire. You have to have either the sensors or the return signal developed by ESC aligned, so they fire the correct polarity at the correct time for both of them. Probably be easier to add sensors if there not already in there.
I knew the experiment result before you started it, because of the physics of running BLDC without sensor. Of course, it's no point in connecting sensors together. This setup will work only in case the motors are ideally synchronized. Any small deviation will lead to oscillation in both motors and reading of feedback by controller will be something weird because rotors are in different positions. This "strange sound" is resonance of this system and in fact it sounds strange not only in resonance. All the time it's consuming excess power to keep oscillations going (but rotors are trying to sync). It's OK to some point when motors are rotating independently without ground contact. If you try to place them on a bike and turn somewhere, there the biggest problem will occur because motor speeds will be slightly different. They can behave unpredictably.
@@TechMasterRus Τhis idea comes from many subscribers, because they find it hard to believe that it will not work properly if we connect two hub motors to one controller... and secondly, there is no video on TH-cam to prove it, so I figured it out and created that Video.
I tried using two motor controllers and two motors connected to one throttle. There must be some kind of feedback because the two motors spin and the power is good, then the controllers immediately turn off or go into so protective mode and are unresponsive. If I turn battery off and on they work again for about one second. Either motor and controller by itself works fine, but together they somehow interfere. The motors are configured (via activating learning mode) to spin in opposite directions since they are left and right wheels and their mounting locations makes that a necessity.
Like stereo, harmonics on two slightly different frequencies due to the reasons you explained. However your test stand may play a part in this as well but only testing would tell for sure. Also, what if you added a third then a fourth hub on this stand and see what it sounds like then. This test was very interesting. Thank you.
Thanks for a great experiment! Newby here. I was considering upgrade options to a 750W48V folder, adding a 500W36V front hub in parallel on a shared 35A controller! hahaha... Maybe just add a 52V20AH batt-w/blender in a rackbag and upping the controller from 22A to 30A? Seems easier adding batteries to a single controller than adding motors...
1. Peak current for one motor was 0.95А. 0.95Ax37.7V~=35W this consumption we see when the motor is under load, starts to spin. After spinning up the consumption falls down to 22Watts. 2. For two motors it was 2.2A(82W) and 1.8A(68W). It is 41W and 34W per motor. Thus two motors in parallel are "less power effictive" than one in about 41/35( or 34/22)=1.17(1.54) times. 3. This demonstration shows only basic values. We still don't know what it means in real life for bike or scooter. For example with two motors there can be less speed and more power(higher acceleration, more average speed on rolling road or mountains). 4. 41W is not dangerous for 250W motorwheel. 5. 2.2A is not dangerous for 15A controller. 6. We don't know minimum resistance limit load on controller and don't know the wheels resistans and that is why it can be dangerous for controller. But i think if it works then it can be used after some temperature tests. Why not?
Twin 350w hub motors in fat wheel downhill bike with 24v 500w bottle and rear rack batteries. Rear rack holding controller unit. All cables routed through jumbo alloy frame. Bluetooth the display and speed sensors. Thats a sensible build.
As a guess I would say its because of the Motor Sensors. The motos get to a certain speed and one of the needs a slightly differnt timing, but the ESC is prolly only doing the toiming based on one of the motor's feedback, then pulsing it the way it thinks it needs. Another intresting phenomena occured but wasnt mentioned. I noticed when he put load on the left motor, the right hand motor slowed down too. Thats going to be to do with the sensors, ill bet! Did you put the sensor wires in paralel or series? or not at all, or only hooked up one motors sensor wires?
This necessarily was running either sensorless, or with the halls from one motor connected. In sensorless, the determination of motor position will be off, because current & voltage are used to determine that, and connecting two motors obviously throws that off. The result is cogging which will vary in severity from loss of efficiency to burning out both motors and possibly the controller.
So what did you do with the other hall sensor wires coming from the other motor? I also imagine both hub motors need to be identical and controller needs to handle double the amps of the motors
Question someone explain please , i thinking about adding duel hub motors kit to my wheelchair from a factory are the compatible with each other ? I'll like to know before purchasing this unit
Not sure this is a good idea due to back emf. I would say under load the controller, and probably the motors will run hot and with low efficiency. The controller uses the back emf for timing, and with two motors connected the timing won't be handled correctly. Interesting concept to try, but in reality it won't work well, or for a long period.
The explanation to the big loss is magnetic induction. One motor create opposite flow of current to the other motor. To overcome the induction the control produce more current to overcome the induction to make the speed of both motors the same. Thats where the 26w came from. Also the battery will suffer in when you use it with a load.
Question I am wanting to make a 4 Wheel drive cart with 4 Independent drive hub motors (48v 800w (rated 600w, max current 30A) geared hub motor for electric wheelbarrow) is it possible to have one controller for this?
No way... the best you can do is to find 2 hoverboard controllers which have 2 outputs for a motors each one... but there you must program them first..
So he joined the three individual wires from the motors. What did he do with both of the hall wires? Did he only hook up one of the hall wires to the Motor controller or both?
yes that will work but remember they are sharing the voltage and current so it wont be double power or speed,it will likely actually preferm in real world worse than a single one unless you get an unlimited controller giving full battery voltage use with a continous 50 amp power handling rating
after alot of trial and error we found that using a cycle analyst ver 2.5 or 3 was the only true way of syncing controllers and motors also lets you set different front and rear power distribution for different terrain and power needs,or even run one in constant generator mode to get bit more ride time.
well done for the experiment i think we can't run the two motors with one motor feedback hall sensors because it is nearly impossible as you said in your video to have the same position and same speed at the same voltage to synchronize the two motors it is like you run one of the 2 motors without a feedback just rotate the field that is the reason of the crawling and cogging (strange sound) so i think we can run the two motors without problem only if we synchronized the sensors signals of two motor (maybe AND gate for the same sensor in both rotor for example (h1motor1&h1motor2)) so we guaranteed the same position of the two motors
The sound difference is just an acoustical phenomena, since the two motors, even if are same model, are not perfectly equal , so there is some sort of beats between the two sounds that are not perfectly the same
I have 2 hubs at 22amps each 36v, I use 2 controllers and one throttle you only need the throttle signal wire on the 2nd controller, obviously, top speed isn't increased but torque and acceleration are great fun but due to lack of weight over the front wheel it spins on hard acceleration from a standstill and the extra weight is a downer. for the extra weight, I'd just buy a new controller with higher amps as long as your battery will take it, but it looks cool with 2wd and lots of people are interested and ask questions if you like being sociable.
Hi. Can you use a wheelchair joystick? I would like to use an e-bike speed controller with high power than a wheelchair controller on a outdoor wheelchair
is it possible to run, along with your existing system(controller, motor and battery) another circuit with motor wired to a button/switch to a battery to act as a secondary for longer rides? 2 drive wheels, but different circuit for each, secondary being push button full speed to save on total battery power?
Good to know, thanks for testing this. I've always wondered what a two hub drive would feel like, but figured the added weight wouldn't be worth it. It would probably make sense to have extra weight at the wheels for a very high power / high torque setup in order to keep traction. I've also been wondering if we ran a 1000w mid drive with a 1000w front hub motor would they compliment each other?
I don't think a front hub and a mid-drive should be mixed as you will never sync the two one will basically always be doing most of the work. You would never be able to sync the Wheel RPMs and depending on your front drive this may actually cause drag on the front wheel.
This could work if you regulated the current to produce the desired torque split. But you would need a computer to set the individual throttles. Your input to the computer would basically be a desired total current and it would adjust the throttles to each motor to achieve the desired total and split. That's pretty much what happens on the dual motor Teslas.
So if I understand this correctly..I have a 1500 rear hub and a 52 volt battery I can get another 52 volt battery and a 1500 watt front hub, put it all together, splice the wires together for the twist throttle and it will all work without letting the smoke out? And I assume that watt usage would be reasonable close to what a single motor would use? Top speed on flat ground will be the same but less decrease in uphill speed. I have a small trailer to pull up a hill..single motor did ok and I kept looking at the skinny ass wires that run to the motor and the fatter wires coming out of the speed controler so I did a voltage drop on each motor wire...over a volt lost. It looks like they had to use skinny ass wires to get through the axle..went to local hobby shop and got some 14 gauge wire the use on rc cars..like 100 strand with silicone insulation. I spiced it in where the wires came out of the axle and ran them to the speed controller and soldered in 30 amp bullet connectors. Top speed didnt change but it accelerates better and takes less throttle up hills...I spent some time looking around to see if anybody else had done it...nope....I see no sense in just giving 3+ volts away..I bought a 52 volt battery for a reason...dont know if the results would be the same with a 48 volt deal but I dont think it makes a difference.
Thanks for testing this. I wondered about building a trike with two motors on the rear wheels, but I think it will be problematic regulating the power to each motor in turns, slippery road etc. I suppose a differential would be necessary?
@@timtreffry7718 i have also been working on a trike problem is how to vary power on the real two hub motors on turning or i can be using differential and a bigger motor ,robert murray smith showed a freewheel differential for trike but it cannot be reversed so i was thinking of using two motors front wheel hub motor and rear wheel geared motor on differential. Now , the issue is to control them with a single controller and throttle.
Well with old school tech it's supper easy. Never tried with modern motors big enough to run a bike or scooter. However brushless setups in models are possible so long as you stay inside your power limits for the speed controller.
Look at how a single works before you connect dual motors. The speed control sends pulses for motor to engage rotation, then motor sends back info about its location relative the stator coils. This info tells the speed control when to send next pulse. When you connect another motor you also get another location info about where the motor are. These signal info may collide or create an duplicated info so the speed control send pulse for a double speed that no motor are at. This configuration will never work good.
So theres a foldable mobility scooter that goes by mulitple names 2 in which are dragon mobility ex and ephesus s5. It has dual rear 8in hub motors 250watt each thats being ran by a single speedd controller rated at 350watt. Correct me if im wrong but doesnt that mean thes motors are nit getting the full 500watt?
Problem with this is when you load those motors since only one gas feedback loop The one with open loop can lose its position and it will start to draw huge amount of current without transferring power And there is a big risk of blowing the motor or controller
Very interesting result! It points to high motor losses and ways to improve it. That fact that total losses are more than the sum means that there are high losses in the controller that increase as more motors are added. This will probably be due to the conduction losses in the controller it suspect, more investigation is needed.
could there be some -off road applications , such as -farming-mowing - hillclimbing , trail riding -ect...that allow for constant "wheel slip"? jeeps of yesteryear were kept in 2wheel drive , -on the pavment-because of simular reason , but off road the wheels slipped in the soft dirt/sand . no problems there , in the 4wheel mode.
If anyone can help I'm looking to pull a diy camper with e-bike but need power assist on the camper. Not sure if I should just use thumb throtle for separate control or just run all on one controller. I'm looking to have 2 750 watt on the trailer and 1 1500 watt on the 3 wheel e-bike.
Series..??? You mean in parallel, yes i know that you can not connect two hub motors in parallel, also i do not recommend that... This video is testing proof for one subscriber..
The sine waves sent to the motor are affected by the motor itself, power is induced in the wires from the magnets passing the lesser powered coils during the cycle. It become an interference pattern with 2 motors
im trying to find out the measurement between the spoke holes on my hoverboard hub ebike conversion so i can start to build my rim for my ebike.before i start to drill my holes for my spokes
[Update on my build below] Great video and awesome (if utterly confusing and contradictory comments!). I'm trying to build an electric hand truck (i.e. convert one to electric) and although several companies make them, the ones they make are over-built for my purposes and VERY expensive (since they're build for industrial use.) I need one to help carry loads uphill on an elevated boardwalk to lake cabin. As far as I can tell, I want low speed and auto-braking and short duration (compared to scooters, etc). The distance is a few hundred feet uphill x 3-5 trips, the weight is
I weigh 360 I want to build a duel motor e-bike with 48v-72v 3000w on one controller but I don’t know what controller to buy ? To put them to run in parallel ?
Running these on the same axle will cause all kinds of issues with torque transfer. An equivalent effect being that of wind up in a locked axle on a car going around a corner. Everytime you turn the wheel you're going to be fighting the motors trying to push the wheels straight again.
@@EVCustoms do you connect both the sets of signal cables in parallel and plug that into the throttle, or is there some other set up that you need to use?
I don't know if anyone has explained this yet, but the problem is magnetic induction in one moter feeding inverse flow into the other. It is creating an oscillation back and forth between the two. As one spins faster than the other it acts as a generator to the other. This is demonstrated when you turn one by hand the other rotates in the opposite direction.this means the moters are constantly fighting each other. If you wish to run two on the same controller you could try either run them in series while doubling your voltage or add some capable diodes to prevent backflow. I would recommend two moter controllers however. One side effect of this is the dynamic breaking, so coasting would be an issue.
And also if these motors are brushless you can't control them with only one controller I think
I dont think you know how these
works yes they dont work together under load I tried but you cant connect 3 phase in series or ad a diode to a ac motor
Clearly people don't know the controller for brushless (AC) uses back feed or hall sensors to know how the motor is positioned. You can't hook 2 together and have the 3 phase timing correct for both. Now brushed (DC) motors you can hook up in parallel and it will work.
It is possible but the controller needs to be modified to stop the feedback from one motor into the other. Open the controller and double every output stage (at least you'll need another 6 N-Channel FETs plus 6 times the SOAR circuit) That way you give your controller a second Motor Output that doesn't feed back.
@@sebastianweinert3802 that would be two in one controller driver .. I think :)
0:31 I've never seen a motors looking so happy before
nice one
The wise thing to do would be to use two speed controllers and two motors connected to a single throttle source. That's how quad copters are built. Each motor has its own speed controller, and the speed controllers are synchronized when you calibrate throttle position.
Yea but quad copters have to regulate all motors independently. The bike would be finde with them running the same speed.
Newsflash ! This isn't a Quadcopter !
blise and chris you are both right but its grossly under powered either way that's a 250w controller and (2) 250w motors in parallel whcih makes them running about 125w a piece. also by adding the other motor you are adding resistance (ohms) to the inner workings of the controller. you've effectively doubled the work that the controller has to do to put out that same 250w. it might work but not for long ESPECIALLY under load.
It would significantly bring the price up.
@@christopherroberts22 you should have said that before I tried flying off the roof.
By the looks of it, it seems to make more sense just to add a second speed controller ( or one designed for dual motor setups.) Either way, it's still a good experiment and I'm glad you took the time to figure it out so the rest of us don't have to
Your assertion at 9:29 is very correct. I was very glad to see that you do not recommend doing this. There are other reasons why this is real bad in real word usage. Watch what happens when you connect the 2 wheels to a common surface where the cant readily slip between each other. Or you can try using a chain or cog belt between them. In other words locking them to try to spin alike. You will burn things because the motors are never identical. I did these tests years ago with help from Neu Motors and Castle Creations.
The noise you are hearing is a harmonic vibration because of the difference between the motors.
Best way to do this cheap is use a common feed to separate controllers. But you can still get fighting between the 2 motor systems because of motor differences.
Now I had great results using the hall effect switches as regulators to make the separate motors spin at the same speed and stay synced. But that took more processing from outside the controllers. Now this could be accomplished with the use of Raspberry Pi or the like.
these motors have one way clutches, so one will drive and not the other until the tires slip. if load increases and causes a speed decrease, both motors speed decrea, so only the wheel with the bigger dia tire drives.
Will George
Interesting. So you lose drive if one wheel out speeds the other but you continue to drain power from your battery. That is a model of inefficient behavior in an electric model. Also the motors are still in essence still fighting each other in my book. The drive sides will always be hitting upon the other. I think it far better to control one then use the Hall effect switch to trigger control of the other. Then the motors will be synchronized. At least that’s how I see it. Maybe I should pull out some parts and revisit this issue.
@@michaelmeisman4731 I think it would be better to drive one motor only, then bring in the other if it is needed. really need 2 controllers
This procedure has been done by electric kick scooter with a dual motor like the Dualtron and others. Mine has a dual drive motor but use only one controller with the same kind of configuration as shown in this video.
If you had a 500W controller would that work?
Nice. I’ve actually did the same thing but instead of one controller I did it with two 48v controllers and 2x 1000 watt hub motors. and rewired the controller to work with one throttle. My goal was for more torque but also gained a little bit of more speed from 28 mph to 34 mph
Forgive me if this is a stupid question Did you wire the same battry pack to the 2 controllers?
Did you wire the same battry pack to the 2 controllers?
@@vladimirryder5195 yea I did use the same battery for both controllers I also made it work with two separate batteries for each controller as well but I prefer the single battery instead.
@@tsmithurst yea I did use the same battery for both controllers I also made it work with two separate batteries for each controller as well but I prefer the single battery instead.
may i knw how to connect two controllers to work with one throttle..Thank you
Running both like this will be fine but they will be noisier under load than normal as no hall effect sensors are used.
Controllers are cheap, so it would make sense to use 2 controllers, then you can use the hall effect sensors. They can both be connected to the same throttle without issue.
I would think there would be miscommunication with the hall effect sensors. They have to be able to tell the motor where the windings are but if both motors are in different positions the controller won't send a proper signal to the motors.
Interesting, I had not even thought about the possibility of running two motors on the same controller, but I find it an interesting experiment.
I have done such a thing although they are 2 hub motors on the same wheel wired in opposite directions. th-cam.com/video/ViZZ0npJKg4/w-d-xo.html
Just because you can do something doesn’t mean you should do something.
That was good.
He learns the lessons so that we don't have to.
Well done.
.
Hi sir . How to make a speed limiter for ebike? Thank you..
I have already video for that...
old time big cassette recorder feeling
Oh yeah spinny matron drums
I suspect this’d be a lot worse on an actual bike. In this setup, the motors are free to ‘align’ their phases, as they’re spinning in air; on a bike, they’d be forced to travel the same speed (staying out of phase) or, even worse, to travel at different speeds when cornering.
not even one day past and I had my question answered super cool thanks to ev costumes for your time
How about mounting it to a common axle? I'm thinking of placing two direct drive motors from a washing machine (which are not the same as these but also BLDC) on the same axle and connected to the rear wheel via a chain. My theory is that if I place hall sensor wires to one of the motors and align them properly in phase they would turn just fine. I'd use a 2kw controller in that case.
I know this video is from four years ago. In that time period commercial e-bikes with dual hub motors have come to market. I have one. Mine is an EMX-Xtreme 500 from Fabulous Ebikes that has two 500w hub motors running on a single KT controller. KT (Kunteng) sell a controller designed to support two motors. In use I'm finding the set-up works really well. With each motor having 80Nm of torque the bike has relatively great acceleration and hill-climbing. On level terrain it appears both motors just share the load put on them by the pedal-assist settings. I can switch on or off the front motor while riding. On level terrain, switching on the second motor does not double the amperage draw. It stays practically the same whether one motor or two. On the EMX-Xtreme 500 the bike comes standard with a 48v 30Ah (1.440Wh) battery. With that I've had real world ranges per charge of 110.4 miles to 156.9 miles. Fabulous Ebikes also sell models with 60v 23.4Ah (1,400Ah) battery and a pair of 750w hub motors, again with a single-controller solution.
I wonder how they would act as two motor rwd cart. I would like to avoid using a diff.
Very good explanation thanks for the video my Friend🙌🙂🤝🤝🤝
Thank you mate! nice channel by the way..
Very nice sir, now you kmow im not lying.. We used 1kw controller on 2 500watts hub motor. I think this setup will burn the controller if the 2 motor have load. Thank you sir
Yes like this can work but i not recommend because like this you will have huge losses...
Price sir 36volt
Really it would? I'm trying to get my bike to synchronize with all three wheels moving with pedal-assist for my trike
@@BORNFREEININTHACD Difficult setup! Though probably not what you want to hear the easiest, troublefree setup would be a single motor/controller front wheel drive. Spitballing here but option two would be a two controllers/two motors probable equipped with hall effect position sensors for both rear wheels. Would need some circuit/microcontroller to act as an electronic "differential" to keep both motors synchronized. Just a semi-educated guess. I have more then 15yrs of BLDC motor/controller experience but not in this application.
@@barthchris1 I have a dual motor electric kick scooter and I looked inside its only one controller the same configuration as this video. Its been using by the E scooter manufacturer with a dual motor.
Sry if this question has already been answered ... with having only the stator windings in parallel and only one motor having the hall sensors connected to the controller, what are the result in Power consumption?
My thoughts ... having dual conflicting input signals is probably having an effect on the controller output. With only one unit giving feedback to the controller, the output frequency will be equal to both units, as the second is purely slave unit with the results being a closer to a doubling of the overall current draw. Now if that slave is proportionally under more load, what is the outcome?
with 2 controllers you still splice in both hall effect sensors for one controll, this is all you had to do and they would sync. In addition they are both running the same direction, one side if used on a trike would require you to swap any 2 wires on the motor going backwards around.
Induction resistance and feed back.
The pluses have a feed back and you're feeding them to the other motor, there is a build up which amounts to the "losses" you saw which is around 50% of the power (cycle).
Put on diodes and a load cap. Then it will work fine.
Isn't the controller and motors miss matched?
Brushless motors cannot be connected in parallel or in series. That would only work if the motors were mechanically connected to each other in exactly the right position and the Hall sensors were only connected to one motor. Exactly this is not possible with our intended use.
Motors with brushes, on the other hand, can easily be connected in parallel or in series.
This was very helpful info since I own a HUNTER QUAD electric scooter. This scooter has 2 motors on the front wheel and 2 in the rear wheel. Each motor rated at 72V 3500w for a total of 14000 watts but it uses 4 X 45Amp controllers. I am currently modifying it with 2 controllers, 1 Sabvoton 72200 for the front and 1 for the rear with a shared thumb throttle. Here's a the video of the scooter and I am the person you'll see speaking on the video.
th-cam.com/video/aBQfs0V3wos/w-d-xo.html
Try with wiring 4 diodes (2 for each motor), in order to eliminate feedback loop.
The motors are out phase. Probably 30-40% of the power when both motors are running is canceling out on the wire. You have to have either the sensors or the return signal developed by ESC aligned, so they fire the correct polarity at the correct time for both of them. Probably be easier to add sensors if there not already in there.
I knew the experiment result before you started it, because of the physics of running BLDC without sensor. Of course, it's no point in connecting sensors together. This setup will work only in case the motors are ideally synchronized. Any small deviation will lead to oscillation in both motors and reading of feedback by controller will be something weird because rotors are in different positions. This "strange sound" is resonance of this system and in fact it sounds strange not only in resonance. All the time it's consuming excess power to keep oscillations going (but rotors are trying to sync).
It's OK to some point when motors are rotating independently without ground contact. If you try to place them on a bike and turn somewhere, there the biggest problem will occur because motor speeds will be slightly different. They can behave unpredictably.
Yes my friend we all knew the result... this video is a simple experiment. ;)
@@EVCustoms but how did you even have such an idea?) It's something like driving a car without differential, really, much worse...)
@@TechMasterRus Τhis idea comes from many subscribers, because they find it hard to believe that it will not work properly if we connect two hub motors to one controller...
and secondly, there is no video on TH-cam to prove it, so I figured it out and created that Video.
I tried using two motor controllers and two motors connected to one throttle. There must be some kind of feedback because the two motors spin and the power is good, then the controllers immediately turn off or go into so protective mode and are unresponsive. If I turn battery off and on they work again for about one second. Either motor and controller by itself works fine, but together they somehow interfere. The motors are configured (via activating learning mode) to spin in opposite directions since they are left and right wheels and their mounting locations makes that a necessity.
Nice , i think you may Use a chunk diod at the end of the motor on the left to not give a feedback voltage and try again.
Can you show a wiring for a button that switches between single motor and dual motor without having to unplug the wires like your doing in the video?
Like stereo, harmonics on two slightly different frequencies due to the reasons you explained.
However your test stand may play a part in this as well but only testing would tell for sure.
Also, what if you added a third then a fourth hub on this stand and see what it sounds like then.
This test was very interesting. Thank you.
You need to add diodes (big ones) between the motors. You have back emf current going from one to another.
I will make one video with diodes my friend..
I'm happy to see that I'm not the only one who knows about amp load increasing to cook the speed control under load.
Thanks for a great experiment! Newby here. I was considering upgrade options to a 750W48V folder, adding a 500W36V front hub in parallel on a shared 35A controller! hahaha... Maybe just add a 52V20AH batt-w/blender in a rackbag and upping the controller from 22A to 30A? Seems easier adding batteries to a single controller than adding motors...
1. Peak current for one motor was 0.95А. 0.95Ax37.7V~=35W this consumption we see when the motor is under load, starts to spin. After spinning up the consumption falls down to 22Watts.
2. For two motors it was 2.2A(82W) and 1.8A(68W). It is 41W and 34W per motor. Thus two motors in parallel are "less power effictive" than one in about 41/35( or 34/22)=1.17(1.54) times.
3. This demonstration shows only basic values. We still don't know what it means in real life for bike or scooter. For example with two motors there can be less speed and more power(higher acceleration, more average speed on rolling road or mountains).
4. 41W is not dangerous for 250W motorwheel.
5. 2.2A is not dangerous for 15A controller.
6. We don't know minimum resistance limit load on controller and don't know the wheels resistans and that is why it can be dangerous for controller. But i think if it works then it can be used after some temperature tests. Why not?
Twin 350w hub motors in fat wheel downhill bike with 24v 500w bottle and rear rack batteries. Rear rack holding controller unit. All cables routed through jumbo alloy frame. Bluetooth the display and speed sensors. Thats a sensible build.
Mr EV, apart from the uneven current voltage, are there any other problems, for using two bldcs with one controller??
As a guess I would say its because of the Motor Sensors. The motos get to a certain speed and one of the needs a slightly differnt timing, but the ESC is prolly only doing the toiming based on one of the motor's feedback, then pulsing it the way it thinks it needs. Another intresting phenomena occured but wasnt mentioned. I noticed when he put load on the left motor, the right hand motor slowed down too. Thats going to be to do with the sensors, ill bet! Did you put the sensor wires in paralel or series? or not at all, or only hooked up one motors sensor wires?
Llegaste a probarlo en una bicicleta para ver si el controlador aguanta los dos motores..??
Phases on two motors are not in sinc, so they technically misfire
on d.c.?
This necessarily was running either sensorless, or with the halls from one motor connected.
In sensorless, the determination of motor position will be off, because current & voltage are used to determine that, and connecting two motors obviously throws that off.
The result is cogging which will vary in severity from loss of efficiency to burning out both motors and possibly the controller.
So what did you do with the other hall sensor wires coming from the other motor? I also imagine both hub motors need to be identical and controller needs to handle double the amps of the motors
Thank you man! Saved me alot of trouble!
Thank you mate..
Cool!! But I wounder if you could run in series instead of parallel.. would love to see this..
Question someone explain please , i thinking about adding duel hub motors kit to my wheelchair from a factory are the compatible with each other ? I'll like to know before purchasing this unit
Not sure this is a good idea due to back emf. I would say under load the controller, and probably the motors will run hot and with low efficiency. The controller uses the back emf for timing, and with two motors connected the timing won't be handled correctly. Interesting concept to try, but in reality it won't work well, or for a long period.
thanks, one question, this kind of motor does not have hall on it right, but if I have two hall sensored motors I could install it with no problem?
The explanation to the big loss is magnetic induction. One motor create opposite flow of current to the other motor. To overcome the induction the control produce more current to overcome the induction to make the speed of both motors the same. Thats where the 26w came from.
Also the battery will suffer in when you use it with a load.
Question I am wanting to make a 4 Wheel drive cart with 4 Independent drive hub motors (48v 800w (rated 600w, max current 30A) geared hub motor for electric wheelbarrow) is it possible to have one controller for this?
No way... the best you can do is to find 2 hoverboard controllers which have 2 outputs for a motors each one... but there you must program them first..
can i use..48v ..controler with two hub 350watt..36v..can speed are increase
So he joined the three individual wires from the motors. What did he do with both of the hall wires? Did he only hook up one of the hall wires to the Motor controller or both?
yes that will work but remember they are sharing the voltage and current so it wont be double power or speed,it will likely actually preferm in real world worse than a single one unless you get an unlimited controller giving full battery voltage use with a continous 50 amp power handling rating
after alot of trial and error we found that using a cycle analyst ver 2.5 or 3 was the only true way of syncing controllers and motors also lets you set different front and rear power distribution for different terrain and power needs,or even run one in constant generator mode to get bit more ride time.
And I'd like to know if you can add multiple battery's and run time without burning up the motors or other parts.
well done for the experiment
i think we can't run the two motors with one motor feedback hall sensors
because it is nearly impossible as you said in your video to have the same position and same speed at the same voltage to synchronize the two motors it is like you run one of the 2 motors without a feedback just rotate the field that is the reason of the crawling and cogging (strange sound)
so i think we can run the two motors without problem only if we synchronized the sensors signals of two motor (maybe AND gate for the same sensor in both rotor for example (h1motor1&h1motor2)) so we guaranteed the same position of the two motors
Great idea I can use that advice for my bike thanks😎
Control individual 2 motors? Left or right? For wheel chair...... thanks
And can two controller work with one hub motor?
Hmmm.. nice question..?
can i ask something, compare 2 controllers 2 bldc with 1 controllers 2 bldc, which is the best? and why?
The sound difference is just an acoustical phenomena, since the two motors, even if are same model, are not perfectly equal , so there is some sort of beats between the two sounds that are not perfectly the same
I have 2 hubs at 22amps each 36v, I use 2 controllers and one throttle you only need the throttle signal wire on the 2nd controller, obviously, top speed isn't increased but torque and acceleration are great fun but due to lack of weight over the front wheel it spins on hard acceleration from a standstill and the extra weight is a downer. for the extra weight, I'd just buy a new controller with higher amps as long as your battery will take it, but it looks cool with 2wd and lots of people are interested and ask questions if you like being sociable.
Hi. Can you use a wheelchair joystick? I would like to use an e-bike speed controller with high power than a wheelchair controller on a outdoor wheelchair
is it possible to run, along with your existing system(controller, motor and battery) another circuit with motor wired to a button/switch to a battery to act as a secondary for longer rides? 2 drive wheels, but different circuit for each, secondary being push button full speed to save on total battery power?
You have two hoverboard motors on one shaft, can you show how you did this please?
Good to know, thanks for testing this. I've always wondered what a two hub drive would feel like, but figured the added weight wouldn't be worth it. It would probably make sense to have extra weight at the wheels for a very high power / high torque setup in order to keep traction. I've also been wondering if we ran a 1000w mid drive with a 1000w front hub motor would they compliment each other?
maybe, the weight might go abit off with the front but should be good
I don't think a front hub and a mid-drive should be mixed as you will never sync the two one will basically always be doing most of the work. You would never be able to sync the Wheel RPMs and depending on your front drive this may actually cause drag on the front wheel.
This could work if you regulated the current to produce the desired torque split. But you would need a computer to set the individual throttles. Your input to the computer would basically be a desired total current and it would adjust the throttles to each motor to achieve the desired total and split. That's pretty much what happens on the dual motor Teslas.
Hahaahaahah!!! Dumbest question of the Day ! well done ;-P
So if I understand this correctly..I have a 1500 rear hub and a 52 volt battery I can get another 52 volt battery and a 1500 watt front hub, put it all together, splice the wires together for the twist throttle and it will all work without letting the smoke out? And I assume that watt usage would be reasonable close to what a single motor would use? Top speed on flat ground will be the same but less decrease in uphill speed. I have a small trailer to pull up a hill..single motor did ok and I kept looking at the skinny ass wires that run to the motor and the fatter wires coming out of the speed controler so I did a voltage drop on each motor wire...over a volt lost. It looks like they had to use skinny ass wires to get through the axle..went to local hobby shop and got some 14 gauge wire the use on rc cars..like 100 strand with silicone insulation. I spiced it in where the wires came out of the axle and ran them to the speed controller and soldered in 30 amp bullet connectors. Top speed didnt change but it accelerates better and takes less throttle up hills...I spent some time looking around to see if anybody else had done it...nope....I see no sense in just giving 3+ volts away..I bought a 52 volt battery for a reason...dont know if the results would be the same with a 48 volt deal but I dont think it makes a difference.
Thanks for testing this. I wondered about building a trike with two motors on the rear wheels, but I think it will be problematic regulating the power to each motor in turns, slippery road etc. I suppose a differential would be necessary?
How did you get on with the trike project? It's exactly what I would like to do?
@@timtreffry7718 i have also been working on a trike problem is how to vary power on the real two hub motors on turning or i can be using differential and a bigger motor ,robert murray smith showed a freewheel differential for trike but it cannot be reversed so i was thinking of using two motors front wheel hub motor and rear wheel geared motor on differential. Now , the issue is to control them with a single controller and throttle.
The contrôler is processing the feedback from all hall sensor at the samedi time?
can you do one throttle running 2 controllers and one power supply?
That would work.
why do you ask not to connect the hall sensors due to risk damage but you seem to be connecting them is there a step your skipping ?
how can i move it in two directions .... can move forward and can move backward???
Well with old school tech it's supper easy. Never tried with modern motors big enough to run a bike or scooter. However brushless setups in models are possible so long as you stay inside your power limits for the speed controller.
Very good vídeo bro!
I'm interested whether 2 500w bafang geared hub motors would run upto 3000w and pedal like a normal bike.
Look at how a single works before you connect dual motors. The speed control sends pulses for motor to engage rotation, then motor sends back info about its location relative the stator coils. This info tells the speed control when to send next pulse. When you connect another motor you also get another location info about where the motor are. These signal info may collide or create an duplicated info so the speed control send pulse for a double speed that no motor are at. This configuration will never work good.
So theres a foldable mobility scooter that goes by mulitple names 2 in which are dragon mobility ex and ephesus s5. It has dual rear 8in hub motors 250watt each thats being ran by a single speedd controller rated at 350watt. Correct me if im wrong but doesnt that mean thes motors are nit getting the full 500watt?
Problem with this is when you load those motors since only one gas feedback loop
The one with open loop can lose its position and it will start to draw huge amount of current without transferring power
And there is a big risk of blowing the motor or controller
What if the motors are physically coupled together so they can't lose sync?
just for curiosity. can we use 2 hub motor 2 different controller in motorcycle. one for power other for regeneration to recharge battery
Very interesting result! It points to high motor losses and ways to improve it. That fact that total losses are more than the sum means that there are high losses in the controller that increase as more motors are added. This will probably be due to the conduction losses in the controller it suspect, more investigation is needed.
could there be some -off road applications , such as -farming-mowing - hillclimbing , trail riding -ect...that allow for constant "wheel slip"? jeeps of yesteryear were kept in 2wheel drive , -on the pavment-because of simular reason , but off road the wheels slipped in the soft dirt/sand . no problems there , in the 4wheel mode.
How much magnetic steel for 250W engine ? You disassembled ?
Would this work better if you had a 500watt controller as both motors equal 500 watts?
If anyone can help I'm looking to pull a diy camper with e-bike but need power assist on the camper. Not sure if I should just use thumb throtle for separate control or just run all on one controller.
I'm looking to have 2 750 watt on the trailer and 1 1500 watt on the 3 wheel e-bike.
Would you be able to pick those dual hubs Motors on a trike
The way trikes generally have a rear axel you might be better off with a “mid mount” style motor
Can put these bad boys on an aquarium. Anything really
@@ななころび you can even put them on your face
And if so how long do you think it will last how long do you think it will run with a atypical linthium battery or even a solar panel.
Try putting the motors in series. If it runs too slow, increase the battery size 6 volts at a time until it runs correctly.
Jim Rojas I dont think you know how a brushless motor works you cant put them in series its physically impossible due to only been 3 phase s
Series..??? You mean in parallel, yes i know that you can not connect two hub motors in parallel, also i do not recommend that... This video is testing proof for one subscriber..
@@nightmareinaction629 You are correct. I thought they were DC motors. Have you tried putting a run capacitor in between each phase?
No my friend i didn't try it...
What if you piggy backed 2 controllers, of the 1 throttle?
That's what you are supposed to do if you want to run two controllers
What is the specifecation for the weel motor ? Voltage and watt?.
Thanks
Is the strange sound an effect of Resonance vibration of 2 identical motors?
The sine waves sent to the motor are affected by the motor itself, power is induced in the wires from the magnets passing the lesser powered coils during the cycle. It become an interference pattern with 2 motors
im trying to find out the measurement between the spoke holes on my hoverboard hub ebike conversion so i can start to build my rim for my ebike.before i start to drill my holes for my spokes
Can I used 36 to 48 voltage 1000 watt controller to drive two 350 watt hoverboard motors.
[Update on my build below] Great video and awesome (if utterly confusing and contradictory comments!). I'm trying to build an electric hand truck (i.e. convert one to electric) and although several companies make them, the ones they make are over-built for my purposes and VERY expensive (since they're build for industrial use.) I need one to help carry loads uphill on an elevated boardwalk to lake cabin. As far as I can tell, I want low speed and auto-braking and short duration (compared to scooters, etc). The distance is a few hundred feet uphill x 3-5 trips, the weight is
How about a used mobility scooter pulling a 4-wheeled garden trailer? Cheap and not a lot of work. And the kids love it with a big seat fitted.
I weigh 360 I want to build a duel motor e-bike with 48v-72v 3000w on one controller but I don’t know what controller to buy ? To put them to run in parallel ?
Running these on the same axle will cause all kinds of issues with torque transfer. An equivalent effect being that of wind up in a locked axle on a car going around a corner.
Everytime you turn the wheel you're going to be fighting the motors trying to push the wheels straight again.
Like and old posi unit from in a car.
How about the break sensing mode for the one hub between the other hub
Can you connect 2 controllers to a single throttle controller?
Yes of course... I have video animation for this.
@@EVCustoms do you connect both the sets of signal cables in parallel and plug that into the throttle, or is there some other set up that you need to use?
Very nice that you show this can be done. Perhaps you could try the experiment again but with a higher ampage speed controller.
Or higher voltage🙂
Does the speed limiter come along with the throttle? What is the throttle you are using ?
Why not letting it run for quite some time and see if it'll overheat or something?
Parallel current = sum of the currents. 250w+250w in this case when the motors are under load. Can you smell the smoke?
so I have TWO 350w hub motor will it work just with one 350w controller ?
How many volts should have the battery for two motors that each have 1000W of power, connected to two controllers?🤔
I tried with 2 different motors... i had some problem but can u confirm that i cant connect a 1000w and a 500w bldc motors? or should i try again?
so now make the hubs turn a 24v 100 amp alternator with serp belt. any power more than it takes to run is free energy ?
Alternator has to be turned on to work, it's not a generator. Plus, what if those are DC motors?