Do dual motors need 2 controllers or is there a single controller option.

[MikeTinkerer]

I have a bike I built and it's current iteration is dual drive electric and gas. I know this site doesn't deal with gas my question is in its current configuration the front wheel is the electric bldc hub 48v 1000w with a 48v 15ah lithium battery. I have a second motor from an earlier iteration it is 48v 500w bldc hub. What I want to do is replace the rear wheel with a motor hub and keep the front wheel motor hub as well.
The question is which wheel should be front and which should be rear as well as if a single controller made for controlling 2 motors is available and if not should both controllers be the same kind?
If it helps the bike in its entirety including the saddle bags containing tools and spare parts weighs 130 pounds I am 5'11" 240 pounds the bike currently has a top speed of 26mph using electric and 50mph using gas. I don't expect more speed from adding the second motor hub just a bit more grunt/acceleration and better control/handling as I use the electric mode as a starter/1st gear/backup propulsion/short non speed critical trips as well as to be considerate of neighborhood noise and just not being a jerk after dark.
Unfortunately $200-$300 is the most I spend on the bike at a time per months pay so that my limit for any suggested controllers.

 

[bananu7]

You will need a second controller. The good news is that there's a lot of cheap options that you can run headless (without an extra display) just by hooking battery and throttle signals to them. If you look around the recent posts there's been a lot of recommendations posted for such.

Also make sure your battery is up for the task. You'll be drawing 50% more power, and if the battery can't handle it, you won't see much increase in performance at all.

 

[MikeTinkerer]

You will need a second controller. The good news is that there's a lot of cheap options that you can run headless (without an extra display) just by hooking battery and throttle signals to them. If you look around the recent posts there's been a lot of recommendations posted for such.

Also make sure your battery is up for the task. You'll be drawing 50% more power, and if the battery can't handle it, you won't see much increase in performance at all.

Thank you I'll look for those posts. I have the battery from the previous iteration but the current battery is 15ah and the old one is 10ah so I can't parallel them. I have read both controllers need to share the same battery so at the least I need to get another 15ah battery which should be ok to parallel with the other since it's only been in use for a few months and has never been depleted beyond 48v from the freshly charged voltage of 54v

 

[bananu7]

Thank you I'll look for those posts. I have the battery from the previous iteration but the current battery is 15ah and the old one is 10ah so I can't parallel them. I have read both controllers need to share the same battery so at the least I need to get another 15ah battery which should be ok to parallel with the other since it's only been in use for a few months and has never been depleted beyond 48v from the freshly charged voltage of 54v

Hmm, as long as you don't link them together, except perhaps signal grounds for the throttle signal, there's no reason why they wouldn't work as two separate systems. One might run out of power earlier but that's about it.

On the other hand, if you wanted to use both batteries for both controllers, then even when nominally matched it would be hard to ensure they perform exactly the same. In that case, assuming either battery can support both motors, it would likely be easier to just have a switch to deplete them one at a time.

 

[stancecoke]

There are several dual motor controllers available. Just take a look at AliExpress:

https://aliexpress.com/w/wholesale-dual-motor-controller.html

regards
stancecoke

 

[E-HP]

Thank you I'll look for those posts. I have the battery from the previous iteration but the current battery is 15ah and the old one is 10ah so I can't parallel them. I have read both controllers need to share the same battery so at the least I need to get another 15ah battery which should be ok to parallel with the other since it's only been in use for a few months and has never been depleted beyond 48v from the freshly charged voltage of 54v

You can parallel the batteries as long as they are the same voltage. You will need to have a routine for charging them (separately) to the same voltage before paralleling. Depending on the type of BMS they have (single port vs dual port), they may even be able to be charged together, which would be a lot less hassle.
One reason that it's recommended to use the same battery for both controllers is that usually the two controllers will need to share a common ground, since in most dual motor setups, they controllers share a single set of peripherals (e.g. a single throttle), and the ground wires of the peripherals will be shared when connected to the two controllers.
Dual motor controllers are just two controllers housed in the same box, with the shared connections wired internally instead of externally, like when using two separate controllers.
Ideally you'd want the controllers and motors to be identical to minimize one motor working more than the other. In your case it will be more complicated. It appears you have a direct drive front motor (most of those 1000w front motor kits are direct drive), and a geared rear motor. Without knowing the speed constants of the two motors, you will have difficulty making them work together and share the load. In your case it's better if the front motor is a faster, if not the same speed as the rear. That's because if the faster front motor is propelling the bike, the rear geared motor can freewheel and not present a drag on the system. A direct drive motor can't freewheel, and will always present a drag on the system if the rear motor is the faster one. I think this will be your biggest challenge when trying to combine the two motors.

 

[amberwolf]

the current battery is 15ah and the old one is 10ah so I can't parallel them

If they're hte same voltage range (same empty voltage, same full charge voltage), then you can parallel them.

Capacity then adds to make them one bigger battery.

If the BMS on both is not common-port type (or you don't know what they are), then you need to disconnect them from each other during charge, and use each one's own charger to charge it.


If they are different voltages, *then* you can't parallel them.

 

[MikeTinkerer]

If they're hte same voltage range (same empty voltage, same full charge voltage), then you can parallel them.

Capacity then adds to make them one bigger battery.

If the BMS on both is not common-port type (or you don't know what they are), then you need to disconnect them from each other during charge, and use each one's own charger to charge it.


If they are different voltages, *then* you can't parallel them.

They are both identical in full charge voltage. The 15ah one has a round 3 prong charge port and the 10ah one has a barrel style charge port. Bothe have the same 2 wire output plug type. I was under the impression 2 batteries needed not only the same voltage but the same capacity as well to prevent one from trying to raise the capacity of the other but it would be more convenient since the throttle is also a voltage meter and key lockout that both controllers would have to share. If the 2 batteries can be used in parallel that would be more convenient thank you.

 

[MikeTinkerer]

You can parallel the batteries as long as they are the same voltage. You will need to have a routine for charging them (separately) to the same voltage before paralleling. Depending on the type of BMS they have (single port vs dual port), they may even be able to be charged together, which would be a lot less hassle.
One reason that it's recommended to use the same battery for both controllers is that usually the two controllers will need to share a common ground, since in most dual motor setups, they controllers share a single set of peripherals (e.g. a single throttle), and the ground wires of the peripherals will be shared when connected to the two controllers.
Dual motor controllers are just two controllers housed in the same box, with the shared connections wired internally instead of externally, like when using two separate controllers.
Ideally you'd want the controllers and motors to be identical to minimize one motor working more than the other. In your case it will be more complicated. It appears you have a direct drive front motor (most of those 1000w front motor kits are direct drive), and a geared rear motor. Without knowing the speed constants of the two motors, you will have difficulty making them work together and share the load. In your case it's better if the front motor is a faster, if not the same speed as the rear. That's because if the faster front motor is propelling the bike, the rear geared motor can freewheel and not present a drag on the system. A direct drive motor can't freewheel, and will always present a drag on the system if the rear motor is the faster one. I think this will be your biggest challenge when trying to combine the two motors.

The 2 motors are the $250 kind bought on Amazon bldc hub motors with no gears just straight motor on axle. The newer one is 48v 1000w and the older one is 48v 750w I rechecked I had thought it was 500 but was wrong. Both motors using the same battery on the same bike achieved the same top speed of 26-28 mph the newer one just had a little easier time accelerating not bad for a 135 pound bike with a 240 pound rider. I hadn't noticed a drag when not on the electric throttle but I haven't tested top speed of the bike with only the gas engine and the electric wheel replaced with a regular wheel but I might have to do that test to check. I am curious if the lower watt motor should be on the front or the rear? The rear wheel is driven by the gas engine by chain to a sprocket stacked with the disco brake on the six bolt disk brake mount on the left the same way I will be driving the electric wheel. I did it this way so I can use electric for riding quietly when going through neighborhood or for short trips that don't require the gas engine and as a first gear/assist when first accelerating. I would also like to use Regen braking to assist in stopping the bike in addition to the front and rear hydraulic disc brakes. The idea of the bike is to have something that can handle everything a daily ride should and never be broken down due lack of a single energy source hence the gas electric pedal while still being cheap enough to replace a blown engine or motor for under $300. Sorry for the rambling thank you for your input on my questions.

 

[E-HP]

The 2 motors are the $250 kind bought on Amazon bldc hub motors with no gears just straight motor on axle. The newer one is 48v 1000w and the older one is 48v 750w I rechecked I had thought it was 500 but was wrong. Both motors using the same battery on the same bike achieved the same top speed of 26-28 mph the newer one just had a little easier time accelerating not bad for a 135 pound bike with a 240 pound rider. I hadn't noticed a drag when not on the electric throttle but I haven't tested top speed of the bike with only the gas engine and the electric wheel replaced with a regular wheel but I might have to do that test to check. I am curious if the lower watt motor should be on the front or the rear? The rear wheel is driven by the gas engine by chain to a sprocket stacked with the disco brake on the six bolt disk brake mount on the left the same way I will be driving the electric wheel. I did it this way so I can use electric for riding quietly when going through neighborhood or for short trips that don't require the gas engine and as a first gear/assist when first accelerating. I would also like to use Regen braking to assist in stopping the bike in addition to the front and rear hydraulic disc brakes. The idea of the bike is to have something that can handle everything a daily ride should and never be broken down due lack of a single energy source hence the gas electric pedal while still being cheap enough to replace a blown engine or motor for under $300. Sorry for the rambling thank you for your input on my questions.

Do you have links to the motors? Most 1000W and above motors are direct drive. Most 750W hub motors (and below) are geared. Searching Amazon, almost all 750W hub motors are geared, but there are one or two direct drive kits with controllers to restrict them to 750W. If you try pedaling the bike with the motor and controller turned off, a geared motor will feel like riding a bicycle. A direct drive will be pretty hard to pedal and even harder the faster you try to go.

If they are both direct drive motors, and they both go the exact same speed using the same voltage, that's a good sign. Assuming the controller and battery are the same, then one motor accelerating more slowly than the other, is puzzling. If one motor had the top speed of 26mph accelerates more quickly and than the one with a top speed of 28 mph, that could indicate a faster winding on one motor than the other (speed and torque are inversely related). However, If one motor is geared, and the other direct drive, then the geared will likely accelerate more quickly when the same power is applied.

If you don't have links, a pic of each motor would help.

 

[MikeTinkerer]

This is the link to the exact one I bought https://a.co/d/3e7pYue the other is identical it only claimed to be 750w and was slightly cheaper at the time. Both motors have the same top speed of between 26-28mph the older one labeled as 750w only took longer to reach top speed and just felt like it was slightly less powerful than the newer one but I had suspected they might be the same motor and the difference could be in the controller since the newer controller is twice the length of the older one and the older one had 2 blue wires to connect to restrict the speed to 10-15. I would switch to a geared motor if my current one is causing so much drag to make pedaling more practical than the last resort it is now. I intended this bike to be complete as a gas bike as well as an e bike and pedaling so your help is appreciated.

 

[neptronix]

There exist many VESC controllers that are designed to run two motors.
The cheapest way to do this is to just have two controllers and two throttles.

You will be surprised at how fast two geared hub motors could be.

A midsize DD hub like the 14lb RH212 will do 35mph and chug up hills like a beast.. could be an option ( one motor is a lot simpler )

 

[MikeTinkerer]

There exist many VESC controllers that are designed to run two motors.
The cheapest way to do this is to just have two controllers and two throttles.

You will be surprised at how fast two geared hub motors could be.

A midsize DD hub like the 14lb RH212 will do 35mph and chug up hills like a beast.. could be an option ( one motor is a lot simpler

There exist many VESC controllers that are designed to run two motors.
The cheapest way to do this is to just have two controllers and two throttles.

You will be surprised at how fast two geared hub motors could be.

A midsize DD hub like the 14lb RH212 will do 35mph and chug up hills like a beast.. could be an option ( one motor is a lot simpler )

Adding a 3rd throttle would be a little tricky I already have a thumb throttle for the electric motor and a twist grip for for the gas engine. I might have to switch to geared hubs with what E-HP has been telling me since if the direct drive hubs I have might be causing a lot of drag when I'm using the engine and if that is the case then the 50mph the engine provides might just be what it can manage because of drag but I need to have the bike functionality.