DIY 6000w Cyclone Motor Mid drive Berg Pedal kart/Quadricycle

[ZNC]

What I have added:

6000w mid drive, 72v 30ah 80a battery, Sturmey Archer QS-RC3 3 Speed Internal gear hub, custom bottom bracket with BSA threads to replace the previous one which was press fit and a custom bracket for the cyclone mid drive, custom 3d printed bracket for the SW900 display, custom 3d printed battery box to fit on the frame, half link chains to replace previous standard chains.

Sturmey Archer Aluminium Quadricycle Hub QS-RC3 - Sturmey archer 3 speed

I don't use the coaster brake I use the disc brake on the other wheel, I got the coaster brake model so it would fit perfectly into the rear bracket seen on 4th picture.

The previous Internal gear hub was a Sram spectro 7 speed which was quite old and not as reliable as a Sturmey Archer.
The pedal kart itself is made by a brand named berg, this particular model that I bought second hand from Germany (they only sold them there I think) is called a Reflex 1 and it came with rear suspension, A single disc brake, front light and there was a rear light which I removed because it was faulty and speedo with dynamo, and Sram 7 speed IGH. They don't make this model anymore and the new ones don't come with these features anymore and now make more simple pedal karts.

 

[SlowCo]

Great build but not sure that the S-A gear hub is going to survive. Why haven't you bolted the 6kW motor directly to the rear axle and used the gears only for the pedals?

 

[ZNC]

Great build but not sure that the S-A gear hub is going to survive. Why haven't you bolted the 6kW motor directly to the rear axle and used the gears only for the pedals?

The sturmey archer 3 speed is in a jackshaft configuration so I would of that it would be fine as long as you ride it appropriately and avoid shifting under load, the go kart is heavy and difficult to pedal even without modifications so that's why I have the motor at the pedals and is a mid drive so it would be a hassle to have the motor at the back, and I want to use the gears with the mid drive.

 

[PaPaSteve]

Well, that looks like fun !

 

[amberwolf]

The sturmey archer 3 speed is in a jackshaft configuration so I would of that it would be fine as long as you ride it appropriately and avoid shifting under load,

The main problem seen with IGH failures from motor drive is shock loading on the teeth that shears them off at the root.

If you add a "cush drive" to the motor-input sprocket of the IGH (or the output sprocket on the motor) it'll reduce that and lengthen the lifespan of the IGH.

Optionally using a controller that can ramp up torque on the motor every time it's started up or torque change is demanded will do something similar.

 

[ZNC]

The main problem seen with IGH failures from motor drive is shock loading on the teeth that shears them off at the root.

If you add a "cush drive" to the motor-input sprocket of the IGH (or the output sprocket on the motor) it'll reduce that and lengthen the lifespan of the IGH.

Optionally using a controller that can ramp up torque on the motor every time it's started up or torque change is demanded will do something similar.

I was thinking of doing exactly what you were saying I'm just unsure of how to do it, I know of tuneable controllers but I don't know how to use them.

 

[amberwolf]

I was thinking of doing exactly what you were saying I'm just unsure of how to do it,

Which one? the tunable controller or the cush drive?

Controller covered below; cush drive is like that on many motorcycles--part of the sprocket mount is metal with fingers that extend down between other fingers on the other half of the sprocket mount, the two are bolted togehther but not clamped tigthly to each ohter, and there are rubber blocks between the fingers to transmit the torque and cushion the startup torque transfer. YOu can buy cush drive parts for various systems and repurpose them, or make your own. Mcmaster-carr and grainger probably carry industrial versions.

I know of tuneable controllers but I don't know how to use them.

Depends on the controller; each one is different. Most tunable ones require complete setup by the user for their system before they can be used. Some have usable defaults for "most" systems but should still be gone thru for all settings for suitability for the user's system. So the manual for the controller will be needed, and so you should make sure that any controller you get has a detailed easily-understood manual. Lots of manualls are pretty crappy, and poorly translated; if you can't follow the manual then don't get that controller.

As far as the tunability required for this purpose, it has to be able to ramp up the phase current to the motor over a short period (or ramp up battery current draw which effectively does the same thing), to cause it to ramp the torque up.

Some really cheap nontunable controllers already have a soft-start throttle response so they take a while to ramp up output to whatever you command, but you can't typically change any of those types of controllers in any way, so you are stuck with the way they work and if they don't do what you want you replace them wiht one that does. :/

 

[PaPaSteve]

For the Bafang motors a shift sensor cuts power to the motor long enough to safely make a shift.
They reduce the shift loads for both IGH and derailleur systems.

 

[ZNC]

Which one? the tunable controller or the cush drive?

Controller covered below; cush drive is like that on many motorcycles--part of the sprocket mount is metal with fingers that extend down between other fingers on the other half of the sprocket mount, the two are bolted togehther but not clamped tigthly to each ohter, and there are rubber blocks between the fingers to transmit the torque and cushion the startup torque transfer. YOu can buy cush drive parts for various systems and repurpose them, or make your own. Mcmaster-carr and grainger probably carry industrial versions.



Depends on the controller; each one is different. Most tunable ones require complete setup by the user for their system before they can be used. Some have usable defaults for "most" systems but should still be gone thru for all settings for suitability for the user's system. So the manual for the controller will be needed, and so you should make sure that any controller you get has a detailed easily-understood manual. Lots of manualls are pretty crappy, and poorly translated; if you can't follow the manual then don't get that controller.

As far as the tunability required for this purpose, it has to be able to ramp up the phase current to the motor over a short period (or ramp up battery current draw which effectively does the same thing), to cause it to ramp the torque up.

Some really cheap nontunable controllers already have a soft-start throttle response so they take a while to ramp up output to whatever you command, but you can't typically change any of those types of controllers in any way, so you are stuck with the way they work and if they don't do what you want you replace them wiht one that does. :/

Thanks that makes sense now.

 

[ZNC]

For the Bafang motors a shift sensor cuts power to the motor long enough to safely make a shift.
They reduce the shift loads for both IGH and derailleur systems.

Yes I was going to order one of these, till then I let off the throttle when changing gears