New member with dual motor setup

[Rlarcier]

Hi
I'm working on a twin motor bike my father started 10 years ago . My father passed away 2 years ago and I would like to finish that project
He was using 2 controllers BAC0281 with 2 GM 250W - I'm looking after the software that I can use to review the setup of the controller
Which software do I use best - Magic Pi3 , Edge ,4,5 ?
When using the software and connecting the controller with the USB cable , do I need to connect any other power source (B-B+ or H+H-) on controller or the controller will get his power from the USB cable ?

I have also installed 2 switches so I can drive either with front or rear or both engines
I'm using contact G (Gate) on the controller to switch off each engine - is that correct - it doesn't seems to stop the engine ?

I managed to have front engine working when connected to controller 1 but then rear engine on controller 2 doesn't work. When I connect rear engine to controller 1 then it works but front engine on controller 2 will not work.
So I'm sure both engines & cabling are fine but suspect maybe a controller 2 config conflict.
The brake switch works fine and open or shut contact between B, Z oV

Any suggestions ?

Tx Renaud

[Bikemad]

Hi Renaud andto the forum.

As you are using BAC0281 controllers, you will need to use the earlier PD_282 Programming software, and with this software, the programming is usually carried out with the battery disconnected (or turned OFF on the battery switch if applicable).

Please read the following installation instructions, especially if you are experiencing problem reopening the software after saving changes:


Click image to view full size.

On some controllers, the gate connection was internally bridged, which means the controller will remain active while the battery power is turned ON.
I suggest switching the throttle signal wires to enable/disable the motors.
The following diagram should also work for the external BAC0281 controllers:



The 12K resistors were required for some Magic Pies to prevent a throttle error when the throttle signal wire was open circuit, but I'm not sure if the BAC0281 controllers will suffer from the same problem.

If you are running both controller from a single throttle, make sure that the +5V supply from both controllers are not joined together, as this can sometimes cause problems.

As one of your controllers works OK and the other does not, it could be incorrect settings in the controller or possible different wiring or even a faulty controller.

Make sure the non-working controller is programmed the same as the working one and then swap the controller wiring harness if necessary.
If the non-working controller doesn't work with the working program parameters and wiring harness, then the controller is probably faulty.

Alan
 

[Rlarcier]

Hi Alan

Tx a million for your guidance

I managed to connect to both controllers using the right software and once I had set the same settings ,both engines started to work together.

I'm currently doing 5 full cycles of charge and discharge to break in the new battery. I was told to do 5 full cycles in totals before settings the Amp back from 5 to 30 continuous and from 20 to 50 peak in the controller config
Do you agree with that ?

Once I have done the break in of the battery I will give it a try at your suggestion to use the throttle wiring instead to use one or 2 engines or both

The reverse switch on the Accel switch is also not working although both controllers have the reverse switch set to enable and I tried - immed and unimmed mode without luck - any thoughts, not that a must have but just fun :-)

Need to fix the rear suspension as the rear shock doesn't seem to coop with my weight. Seems to loose air pressure. I will install another one to see if better

For the rest happy I managed to get it working. The pic of the beast :-)

[Bikemad]

I'm pleased to hear that you've got both motors working, but the 902 mini motors are unable to produce any torque in reverse due to the internal unidirectional clutch.

Without know what voltage motors and battery you are using it is difficult to know what the best settings will be, but I would not set them anywhere near the controller's maximum settings as passing too much current through the mini motors can strip the teeth off the nylon gears and also overheat the windings, which sometimes melts the insulation on the wires resulting in a short circuits:



Drawing just 10 amps at 36 volts (or 15 amps at 24 volts) equates to 360 watts, which should produce an output power of 288 watts at 80% motor efficiency, which is already more than the 250 watt rated power for the mini motors.

However, I suspect that your smaller diameter wheels and dual motors will be less susceptible to overheating as they should be under a lot less load than an identical single motor in a larger diameter wheel.

Alan
 

[Rlarcier]

HI
Hi
tx again for quick response
It is a 36V (14,4Ah) battery and engines are 36V 250W engines. From 10 years ago but never used. Battery is new
I'm putting it under stress with hill climb and my 114kgs :-) with the setting - Continuous 5 Amp and 20 Peak. It is not hot at all.
Given the small wheels and the fact it doesn't seem to warm up at all would you give it a 7 continuous (200W at 80% efficiency) and 9 at peak(259W at 80% ) ?
Or I should even lower both values as those engines will never give 250 at 80% ?
Sorry for my dummies type questions. I have only some very basic electricity expertise
Tx Renaud 

[Bikemad]

If they're not getting hot then 7A continuous and 9A peak should  be fine.

If you find this does not give sufficient power for hill assistance you may be able to increase it slightly, but make sure the motors are not getting too hot.

Alan