Front hub 48v motor for very hilly area

[BidelloZ]

Right, order placed!

Went for the SWX02 48v500w 400rpm, 48V 22A sine wave controller, LCD3, throttle and PAS, all from C&D.

Asked about the stamping on the motor, they sent me this picture. Guess I’ll have to do some work prior to installing everything...

 

[vfr400]

That'll be Ok on the flat, but wi

It's always very important that you choose a motor speed that suits your modal travelling speed, considering weight and hills as well..

I can't see much problem with that arrangement for a normal person on a normal bike doing normal rides. Even steepish hills won't be a problem, but add two kids in a trailer and steep hills could be a problem.

It'll probably get very hot going up hills, and it'll probably also overheat the controller because the controller is only rated at 11 amps. It can provide up to 22 amps for a short time, like short hills and starting off. Once you get up to a speed of around 12 mph, the motor will become more efficient, and it'll regulate the current because of the back emf. below that speed, you'll probably get the full 22 amps all the time (assuming level 5 for max power), which will overheat the controller and probably the motor too. Don't forget that the controller is only rated at 11 amps continuous, but will allow anything up to 22 amps.

Whey you first take the kids up a steep hill, stop a couple of times to feel how hot the controller gets. if it gets to a temperature that's uncomfortable to hold your hand on, stop and let it cool down, then think about where you can mount it in the open.

 

[BidelloZ]

OK, so I've made a mistake then?

I thought the 48V SWX02 was going to be the best option for my situation - me + bike + kids + 180 Kg easy.

Should have I chosen the 350W version at lower RPMs?

Should have I gotted a higher current controller, like 40A to be on the safe side?

I can still amend the order if anything.

Many very thanks

 

[Woosh]

I thought the 48V SWX02 was going to be the best option for my situation - me + bike + kids + 180 Kg easy.

The branding does not matter, concentrate on the basics.
As I understand, high speed is irrelevant, you are carrying your kids.
You need to optimise the maximum power point where it's most needed.
This is the point where your motor produces most W. this is important to build a good e-bike.
Let's assume that you run 48V 22A controller, at a typical 66% yield when climbing a steep hill, one third goes to produce heat, two thirds go to produce mechanical power. The maximum pulling power is 48V *22A *0.66 = 697W.
concentrate on the steepest portion of your route, estimate the maximum speed you can get from your motor giving the voltage and Amp rating of your controller.
For example, pulling 180kgs up a 10% gradient, your speed is 7.8mph, 130RPM.
https://www.ebikes.ca/tools/simulator.html?batt=B4814_EZ&cont=cust_22_22_0.03_V&grade=10&axis=mph&mass=180&wheel=20i
If you choose a fast winding, the yield will drop when you need to get more Watts out of the motor, you simply turn more battery into heat and cook the motor in less than a 1000 miles.
Choose a motor which is rated nearest to 130RPM /.7 = 185RPM.
201RPM is a good choice.

 

[BidelloZ]

The branding does not matter, concentrate on the basics.
As I understand, high speed is irrelevant, you are carrying your kids.
You need to optimise the maximum power point where it's most needed.
This is the point where your motor produces most W. this is important to build a good e-bike.
Let's assume that you run 48V 22A controller, at a typical 66% yield when climbing a steep hill, one third goes to produce heat, two thirds go to produce mechanical power. The maximum pulling power is 48V *22A *0.66 = 697W.
concentrate on the steepest portion of your route, estimate the maximum speed you can get from your motor giving the voltage and Amp rating of your controller.
For example, pulling 180kgs up a 10% gradient, your speed is 7.8mph, 130RPM.
https://www.ebikes.ca/tools/simulator.html?batt=B4814_EZ&cont=cust_22_22_0.03_V&grade=10&axis=mph&mass=180&wheel=20i
If you choose a fast winding, the yield will drop when you need to get more Watts out of the motor, you simply turn more battery into heat and cook the motor in less than a 1000 miles.
Choose a motor which is rated nearest to 130RPM /.7 = 185RPM.
201RPM is a good choice.

Many thanks Tony, appreciate your help.

Well I have used that calculator and in fact I thought a 201 rpm motor was going to be best, given that as you say a motor designed to spin at higher speeds will become progressively less efficient when forced at lower speeds and thus whatever the current applied, this will be turned into heat. Hence I was thinking of the Q128.

However I still wanted the SWX02, which is only available in these two configurations:

- 48V350W @235 RPM
or
- 48V500W @400 RPM

I've ordered the 500w, 400RPM version
And the 22A controller.

Should I amend my order and get the 325 RPM motor, and a higher rated controller?

Cheers

 

[vfr400]

I think that the 325 rpm motor will be the best for what you want. Don't worry about whether it says 350w or 500w in the listing. That's completely irrelevant and misleading.

 

[BidelloZ]

I think that the 325 rpm motor will be the best for what you want. Don't worry about whether it says 350w or 500w in the listing. That's completely irrelevant and misleading.

Thanks again for the support ;-)
Worth getting a 40A controller too?

Cheers

 

[vfr400]

Thanks again for the support ;-)
Worth getting a 40A controller too?

Cheers

22 amps one should be Ok at that speed.

 

[BidelloZ]

Awesome!

Again, thanks so much to you, Tony and others that took the time to read and reply!

 

[BidelloZ]

Well I placed my order on the 9th, it arrived all today! I’m impressed, first time I ordered from Aliexpress!

All looks good. Did a test run too with my battery, motor spins nicely and not too fast = hoping for some mean pulling abilities

Now only need to find the time for the build...pics and report to follow.

Many thanks again for the help

 

[vfr400]

Looks like a code 13, which is perfect at 48v in a 20" wheel. It should give 18 mph max.

 

[BidelloZ]

Looks like a code 13, which is perfect at 48v in a 20" wheel. It should give 18 mph max.

Perfect, hopefully it's just what I need.
I don't think I'm going to bother with scrubbing the laser stamping down, it looks pretty innocuous and non-obvious.

One question: do these motors have a thermistor at all? I've seen a temp setting on the LCD3, would be nice to know when the motor is heating up and needs a rest, to avoid cooking it that is.
Any way to tell from the wiring, or do I need to open it?
I'd be tempted to implement the mod as per this link posted earlier on this thread:

Electric Hub Motor Tuning

Tuning an electric hub motor is a relatively straightforward thing. The biggest obstacle to overcome is excessive heat build-up in the hub motor. Most hub motors are cheaply made in great volume. T…

etrike.wordpress.com

Filling up the drum with automotive oil in order to remove the air gaps and provide better heat dissipation, but for the time being I think I'll just be trying the motor out on the slopes and see how it performs...

 

[Nealh]

Perfect, hopefully it's just what I need.
I don't think I'm going to bother with scrubbing the laser stamping down, it looks pretty innocuous and non-obvious.

One question: do these motors have a thermistor at all? I've seen a temp setting on the LCD3, would be nice to know when the motor is heating up and needs a rest, to avoid cooking it that is.
Any way to tell from the wiring, or do I need to open it?
I'd be tempted to implement the mod as per this link posted earlier on this thread:

Electric Hub Motor Tuning

Tuning an electric hub motor is a relatively straightforward thing. The biggest obstacle to overcome is excessive heat build-up in the hub motor. Most hub motors are cheaply made in great volume. T…

etrike.wordpress.com

Filling up the drum with automotive oil in order to remove the air gaps and provide better heat dissipation, but for the time being I think I'll just be trying the motor out on the slopes and see how it performs...

No, thermistor or sensor for it. I thought the same when I got my lcd3, but as vfr said there is no extra wire for one.
The lcd just reads ambient air temp.

Oil cooling isn't really needed unless you hot rod the motor with 30/40a and high voltage, only advantage is if you live/ride in hilly terrain a lot.

 

[BidelloZ]

Update:
Picked up the wheel, looks nice

Before dropping it at the workshop I couldn’t help myself and opened up the hub. Nice stuff, surprised about the lack of grease though. Added some just in case.

Also, doesn’t that component look like a thermistor? Probably just got the look though...

Will report back after the first test ride

 

[Nealh]

Last pic, you have what is known as a Torque arm in your hand.

 

[BidelloZ]

Last pick, you have what is known as a Torque arm in your hand.

Yep, bought two just to be on the safe side.

OK first run impressions: it does pull up nicely! Fairly quiet too.

Nice, and slow. VFR400 was spot on: 18.4 mph top speed!

I have to test it with a full load of kids, but seems promising nevertheless.

I have to install the torque arms but they’ll need sole modding: one will share the IS fork caliper hole, the other one of the mudguard bolts.

Next of course proper cable routing, waterproof controller box, etc.

Still thinking about a torque sensing BB. Been in touch with Grin Tech, simpler solution would be a Sempu BB and a CA3 to read the toque sensor output and feed a voltage signal into controller via the throttle connector. Neat for sure, but am questioning myself as to whether makes sense at all to shell out some more £££ to only gain a better feel when pedalling. Might (and probably will) pass for the moment.

More pics and impressions to follow

 

[sjpt]

We've got a torque sensing solo (Raleigh Motus) and rotation sensing tandem (Woosh XF07 kit, with throttle we never use). The torque is more 'natural' feeling, but I like the way you can phantom pedal with the rotation sensing when you are feeling lazy. Your idea to wire torque sensing up to where it expects a throttle should give the best of both systems; I don't think I'd bother or shell out the £££ if it was me, though.

 

[BidelloZ]

We've got a torque sensing solo (Raleigh Motus) and rotation sensing tandem (Woosh XF07 kit, with throttle we never use). The torque is more 'natural' feeling, but I like the way you can phantom pedal with the rotation sensing when you are feeling lazy. Your idea to wire torque sensing up to where it expects a throttle should give the best of both systems; I don't think I'd bother or shell out the £££ if it was me, though.

Yeah I'm not going to bother - the CA3 alone, either bought from Canada or various resellers (UK, Germany, etc) is around £140-170.
Plus another £70 for a Sempu TS.

I think at the moment I'll be OK with what I've got.

On a second note. This is interesting.

Speaking to a colleague at work yesterday, it has emerged his mate recently bought a mid drive motor from a shop here in the UK, but wanted to get rid of it.

Just seen this guy and saw the motor.

It's an 48v TSDZ2 from Woosh.

He installed it on his (rather basic) commuting bike, as far as I understand with a set of LiPo packs he had lying around. Apparently managed to damage the motor during installation, stripped the M8 thread where the rear support bracket goes. He did manage to finish the installation anyway (don't ask...used some steel wire and a clamp...).
Anyway he used the bike and said he really like the motor, so much he finally decided to splash out for a proper new ebike.

To cut the story short, I'm taking this TSDZ2 home. For the little money I've managed to secure the kit, it was worth it. Thought I could always re-thread the hole and sell the motor. But today I'm off work, family away and have some time to play.

More later

 

[Woosh]

the M8 bolt is a bit oversized.
Its job is to stop the motor from rotating around the bottom bracket shell.
there is not much load on it, any simple repair will hold.

 

[BidelloZ]

the M8 bolt is a bit oversized.
Its job is to stop the motor from rotating around the bottom bracket shell.
there is not much load on it, any simple repair will hold.

No repair needed, I just cut off the whole support in order to fit the motor to by BB.

Also have dremelled (is that a word?) out the whole support on the motor cover and fabricated a custom support.

I know Tony you never recommend the TSDZ2 for my cargo bike, but given I’ve got this motor almost for free (yep that’s right) I thought it’d be fun to give it a go.

EDIT: I'm very happy with the 48V SWX02, it's quiet and seems to which up the cargo bike no problem. This TSDZ2 thing happened basically overnight, an a combination of curiosity, spare time and mostly the fact I got the motor for the price of a dinner for two did the rest

Now I'm in the very unique position to test both motors and draw real impressions.

Will test it this afternoon.

Pics of the butchery