My Non Hub Motor Cargo Bike

[rollingreenhills]

I am about to swap out the drive system on this cargo bike of mine which I was a bit disappointed with.

This is my first ebike build, and I have learnt a lot, the biggest ones are that torque is very important, and that 24 volts is not great owing to high amps required to up power. Correct me if I am wrong.



The original design was to have a rear wheel driven bike, but this caused all sorts of problems. So next up I mounts the motor of the front of the bike, which works fine, but the bike usefulness is limited by the lack of torque provided by the motor, which is only 9.7nm. . .



I have in the post a Bafang BPM 48v 500w which I hope (and expect) will be better.

Here are some links if you are interested:

Building the frame: http://dorkythorpy.blogspot.co.uk/2015/08/diy-long-tail-e-bike-chapter-2.html

Front wheel drive method: http://dorkythorpy.blogspot.co.uk/2016/01/chain-driven-front-wheel-drive-ebike.html

Trike Conversion: http://dorkythorpy.blogspot.co.uk/2016/01/thorpys-guide-to-bicycle-sidecars.html

 

[LyonNightroad]

 

[rollingreenhills]

:lol:

 

[gogo]

How many amps is your controller rated for? That brushed motor looks like it should be able to put out sufficient torque. Its main drawback is efficiency, not lack of torque. Currie uses 35A controllers on its 450W 1018z eZip.

 

[rollingreenhills]

thanks gogo

yes it is a monster, however in the specs it does say 9.7nm torque.

I think (?) most geared hub motor of 4 - 5 times that at least.

The controller is a 500w brushed controller from ebay rated at 25A.

http://www.ebay.co.uk/itm/24V-500W-Electric-Bicycle-E-bike-Scooter-Brush-DC-Motor-Speed-Control-Controller/151894153780?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D36383%26meid%3D0e6bb21c5337411aa0fcf1952e6cf5a9%26pid%3D100005%26rk%3D4%26rkt%3D6%26sd%3D281749047078

The problem is I am largly new to electronics and I am worried about damaging things.

I have seen higher ampage controlleres such as the one on this page at 800w:

http://www.electricscooterparts.com/speedcontrollers24volt.html

But would this translate as a say 40% more torque? I need 3 times as much torque. I live in a hilly area . .

Greaful for advise.

Will

 

[gogo]

I think your expectation that geared hubmotors will give 4-5 times as much torque is not realistic. At similar wattages, single speed systems should be within a plus or minus of 1X in performance at the most.

I suspect your batteries. Lead acid batteries can deteriorate quickly even with good care. With less than good care they can go bad very quickly. Have you tried watching your battery voltage during operation? Voltage sag would show if your batteries are your weak link. Put your meter across each battery separately while under load to compare and see if one is worse.

Your brushed geared motor should be capable of giving better start-off torque than a brushless geared hubmotor. An 800W controller should allow more torque, and if you're judicious with the throttle would be ok. I'd put a temperature sensor in the motor to help keep from overheating.

 

[rollingreenhills]

Dear Gogo,

Thank you for you reply. I have moderate to high confidence in my batteries, they are panassonic branded and bought brand new, and the performance has not alterred, although this is based on subjecture rather than anything else.

My Bafang BPM arrived yesterday (I had to pay the couier import costs!- Elife Bikes) and I will try this out and see if it is any better.

Another problem I forgot to metion is the noise which comes from the brushed motor. When carrying a passenger it is hard to have a conversation!

Thank you for you advice, I may retain to brsuged setup and try out with 800w controller at later date.

Kinds regards,

W

 

[gogo]

Noise alone is reason enough to use a hubmotor.

Maybe you could add a a sprocket adapter to your hubmotor and use both for hills, if needed. Your lead batteries would be capable of feeding both controllers.

 

[wineboyrider]

The motor looks like a MY 1020 which is a pretty powerful motor. You could easily put 2000w through it.

 

[rollingreenhills]

Oh, that is interesting wineboyrider. That sound chain snappingly powerful!

I may try that in the future.

Would that require upping the voltage?

Would there be any benefit from run the 1020 at higher RPM, with lower gearing? Whcih I guess would happen at a higher voltage.

I guess I am asking what would be the ideal controller for the 1020?

 

[gogo]

Using The Currie eZip 24V 35A controller on their 450W motor as a comparison, you could try that with a temperature sensor in the motor.

The maximum gearing would be where your desired top speed is 75% of the no-load speed. The no-load speed is measured at full throttle with the wheel off the ground. If that's not enough torque on hills, then you'd want to change the gearing for less top speed, more torque.

I wouldn't run the motor (before its gearbox) at much more than 3000 RPM.

Just adding another 12V battery to your system would increase the motor phase amps (current), if your controller will tolerate the increased voltage. The LVC would still be set for the 24V operation, though. Note: Currie eventually designed their controllers to limit the input voltage, but most cheap controllers probably don't.

You could also modify your controller to output more amps @24V by strategically applying a blob of solder to the resistance-measurement (shunt) wire. The risk would be overheating your controller.

The weak link might be the size of the controller's phase wires, but you could shorten them up by putting the controller near the motor, or put bigger wires in your controller.

 

[wineboyrider]

Oh, that is interesting wineboyrider. That sound chain snappingly powerful!

I may try that in the future.

Would that require upping the voltage?

Would there be any benefit from run the 1020 at higher RPM, with lower gearing? Whcih I guess would happen at a higher voltage.

I guess I am asking what would be the ideal controller for the 1020?

24-60V 700-1000W Electric Scooter/Bicycle Speed Controller
24-60 Volt input range. Works with 24-36 Volt motors up to 700 Watts, and 48-60 Volt motors up to 1000 Watts. Under Voltage protection 20.5 Volts. Current limiting feature prevents controller and motor damage due to over-current conditions. Includes a standard variable speed hall-effect throttle with grip and a matching right hand side grip. Works with 24, 36, 48, and 60 Volt battery packs.
Item # SPD-601000A
The yi yun controller. I have one it's awesome can run 24 x 25 amps=500w or up to 60v for 1500w. It's a solid controller with good heat sink and simple wiring. Just be careful running at higher voltage as the lvc is set for 24 volts.

 

[wineboyrider]

This controller is probably one of the very best brushed motor controllers for scooter and ebike use. I have used the currie controller, but wiring is complicated with some of the other controllers and they tend to go up in smoke...... :lol:

 

[gogo]

This controller is probably one of the very best brushed motor controllers for scooter and ebike use. I have used the currie controller, but wiring is complicated with some of the other controllers and they tend to go up in smoke...... :lol:

That's the Yi-Yun YK-43b. Its known to allow 50+ Amps from the battery and act like it doesn't have any current limiting. I wouldn't use that with any battery except lead acid. I toasted some Milwaukee toolpack BMS and also a ping BMS using that controller. It might be ok with his 22AH SLA batteries.

One of the other Yi-Yun controllers with a stated current limit would probably be safer for anything with a BMS.

 

[wineboyrider]

Mine shows peak amps of 35 amps, but it on 24v would do the trick

 

[gogo]

Mine shows peak amps of 35 amps, but it on 24v would do the trick

Are you using any sort of BMS?

 

[rollingreenhills]

I really should have posted here before I went "shopping" it seems I could have got a lot more welly / oomph out of my 1020 .... this might have been worth trying before I purchased hub motor.

I had kind of given up on this system. But I think with a high amp controller (as people are suggesting) and a temp sensor on the motor it may have worked well.

As if by penance the hub motor has been a dog to fit, and I havn't even got to the electrics yet!

The forks fouled on motor casing.

The disc brake fouled on the fork stanchion.

The overlock (effective) dimension is not standard, it is over 100mm by about 5mm.

I have had to use a welder, lump hammer, and hack saw to get it to fit.

Plus (yes there is more) the chinese built the wheel with zero dish, so that has had to be dished. . . I am almost looking forward to building the battery pack!

Thanks again for all the useful information. That yi yun controller sounds like a beast!

 

[wineboyrider]

I use naked lipo.

 

[wineboyrider]

I kept the controller because I like to buy electric scooters on craigslist. You can usually get them real cheap once the batteries die. I got another schwinn scooter for my son the other day, but it still has the stock controller in it. My blue scooter with this yi yun controller could do wheelies on 12s lipo 8)

 

[gogo]

I kept the controller because I like to buy electric scooters on craigslist. You can usually get them real cheap once the batteries die. I got another schwinn scooter for my son the other day, but it still has the stock controller in it. My blue scooter with this yi yun controller could do wheelies on 12s lipo 8)

OK, I hadn't thought of using naked lipo. The YK-43b is truly a beast and I've never heard of one failing, maybe because it fries the other components first.

rollingrenhills, sorry to hear of your installation woes, but thank you for posting your experiences for us. I like your cargo bike.

 

[rollingreenhills]

Well I have finally got my bike up and running again, with the hub motor set up.

It is a LOT quieter, and about 50% (ish) more torque, the low speed torque is rock solid, it drops down to a certain speed and just stays there. Oooomph!

Thanks for all advice.