Is the SWX02 quiet?

[1boris]

beside wear and tear, one important consideration is the likelihood of failures.

Motors often fail because:
1. hall sensors die
2. magnets get detached from rotor
3. overheating causing insulation to melt

When you use a high reduction ratio motor, you are likely to need hall sensors. The sensorless These sensors are sentitive to heat. Sensorless motors are not affected by this problem.
Higher rotational speed means higher probability that when you run over a pot hole on the road, your rotor hits the side of the stator and causes a magnet to detach.
The reason to have higher reduction ratio is to produce more power with less copper. Motors are still made of steel and copper. More steel and copper can handle more power and dissipate more heat. The Q128H has less steel and copper in comparison.
The gearbox in the Q128H has two stages, 6 nylon cogs compared to single stage, 3 nylon cogs on the SWX02. I think that the Q128H gearbox wastes more energy.

The Q128H I can assure you takes a lot more to get hot than your SWX02 motor.I think you say a lot of bullshit about your motorss.For example like when you said your BPM motor could compete hillclimbing wise with the bosch cx

 

[Woosh]

.I think you say a lot of bullshit about your motorss

do you have access to these motors?

Ask yourself why, despite being cheaper to buy, nobody uses the Q128H in their mass production bikes?
and why the SWX02 is widely used?

 

[Deleted member 4366]

Ask yourself why, despite being cheaper to buy, nobody uses the Q128H in their mass production bikes?
and why the SWX02 is widely used?

That's easy. it's because most of the people that buy bikes from China haven't a clue. They just accept what their factories offer. Like in the UK, the factories just use the motors from the company that gives them the biggest backhander.

I've been on both this forum and Endless-sphere for 7 years and I've never heard of a magnet detaching from a geared hub-motor.

 

[Woosh]

I've been on both this forum and Endless-sphere for 7 years and I've never heard of a magnet detaching from a geared hub-motor.

you wrote this 7 years ago:

I doubt very much that the cracked magnet is causing your problem. If it's loose, mark it, take it off and glue it back with a bit of epoxy.

Here is one from ES:
https://endless-sphere.com/forums/viewtopic.php?t=340#p18936

2. some magnets known to come unstuck

Lots more - search for 'unstuck magnets', if you bother to look.

 

[Deleted member 4366]

you wrote this 7 years ago:
Here is one from ES:
https://endless-sphere.com/forums/viewtopic.php?t=340#p18936

Lots more - search for 'unstuck magnets', if you bother to look.

Jeez! What are you trying to prove by quoting me from a thread about a unicycle, who's motor is highly unlikely to be a geared one. How would it stop?

The other example is from 10 years ago about a Tongxin motor. Is that relevant to today's geared hub-motors? It didn't even have gears!

Please stop trying to mislead people. If they can't trust your posts, they'll lose trust in your bikes.

 

[Woosh]

Please stop trying to mislead people. If they can't trust your posts, they'll lose trust in your bikes.

I have always backed up my reasoning with evidence from others.

You know as well as I do, fried Hall sensors are the major cause for failing motors. There must be a hundred posts here and on ES about dead sensors. You also know that the issue of glue used to bond the magnets on rotors has been discussed many times, heat causing magnets getting loose then the loose magnets getting knocked out when you ride over pot holes.

'My Crystalyte 408R motor started to make a squeak squeak '

https://endless-sphere.com/forums/viewtopic.php?f=2&t=10696&start=0


I could not find a video of geared hub motor with loose magnets, this one is of a driect drive but the principle is the same:

 

[Woosh]

some more links if you are interested:

http://visforvoltage.org/forum/5174-wilderness-energy-bd36-magnets-coming-loose-after-3-years

'I have an odd sound coming from my hub motor.'
https://endless-sphere.com/forums/viewtopic.php?t=27079

 

[Deleted member 4366]

You're just making yourself look silly now. That first link is from a post on a forum 9 years ago about a motor that was even older. It was an old brushed motor that's hardly been seen since. if you go back 10 years, just about everything from China broke, but that's not the same today.

The second post you referenced was about a guy that thought he might have a loose magnet, but it turned out that it was a broken spoke. Even that was from 6 years ago.

If loose magnets were a problem on geared hub-motors, you'd be able to show us some photos of your own. I repair loads of motors for various people and I've never seen anything like it.

Your theory about hall sensors cooking is also probably wrong. They blow alright, but most that I've seen have been caused by problems outside the motor, like damaged or shorted hall wires, misconnections and controller faults.

Finally, the biggest problem with hub-motors is water getting in and making them go rusty, not any of the things you mentioned.

 

[Woosh]

You're just making yourself look silly now. That first link is from a post on a forum 9 years ago about a motor that was even older. It was an old brushed motor that's hardly been seen since. if you go back 10 years, just about everything from China broke, but that's not the same today.

I gave my reasoning and supported it with evidence by others. Unlike you, I don't think that suppliers are blindly led by the factories that they buy from. Their choice of Bafang SWX02, 7 and 8, all 140mm motors are probably founded by the same reasons that led me to select the SWX02, after testing various samples, including the Xiongda XD.
As I said before, if I have a bit of free time this week, I'll make a video comparing the two, Q128H v SWX02. You have both, you can do that as well.

 

[1boris]

do you have access to these motors?

Ask yourself why, despite being cheaper to buy, nobody uses the Q128H in their mass production bikes?
and why the SWX02 is widely used?

I have compared the Q128 to the BPM and to the bbs 48v 20 a on a very steep long off road here in Norway.The BPM couldnt make it without overheating.The bbs 500w was hotter than the Q128H at the top.They are both inrunners.It was about a 20min trip.The Q128H had a top speed about 43-44 kmh on the flat throttle only.48v 18a and the torque wasnt far from the bbs 500w.I was really impressed.

 

[Woosh]

I use the bmsbattery kit Q128H, 48V 20A controller. The KT LCD that comes with the kit displays also in Watts. I hooked it up to a variety of motor wheels and also the GSM crank drive.
The kit pumps into the motors exactly 800W in all cases.
My result is different, the Q128H is good but the SWX02 is better. As I said before, if I have free time, I'll make a video.

 

[1boris]

I use the bmsbattery kit Q128H, 48V 20A controller. The KT LCD that comes with the kit displays also in Watts. I hooked it up to a variety of motor wheels and also the GSM crank drive.
The kit pumps into the motors exactly 800W in all cases.
My result is different, the Q128H is good but the SWX02 is better. As I said before, if I have free time, I'll make a video.

Dont know how you get diffrent results,but from my experience I know it is bullshit.
Since you have so much freetime you maybe should back up your claim about yor BPM motor and make a hillclimbing video test of it against the Bosch CX

 

[Woosh]

I did hook up a BPM to that kit. Same bike, same controller, same battery.
The tests use throttle only to get to 800W ASAP.
The only difference is the motor wheel.
Did you use the same bike, controller and battery in your tests?

 

[Woosh]

Since you have so much freetime you maybe should back up your claim about yor BPM motor and make a hillclimbing video test of it against the Bosch CX

the Bosch CX does not have a throttle - can you figure out how to test?
If I hook up the bmsbattery kit to the BPM and the same guy pedaling as hard on both bikes, the BPM would win.

 

[1boris]

the Bosch CX does not have a throttle - can you figure out how to test?
If I hook up the bmsbattery kit to the BPM and the same guy pedaling as hard on both bikes, the BPM would win.

You have to use the BPM bike as you are selling,not a modded version.D8veh is right you are making yourself look silly.You skouldnt have to much freetime

 

[Woosh]

that's where we differ.
I have to compare motors on the same test rig, you don't.

 

[Woosh]

You have to use the BPM bike as you are selling,not a modded version.

the Big Bear I am selling has a 20A controller, it has about the same output as the CX.

 

[1boris]

the Big Bear I am selling has a 20A controller, it has about the same output as the CX.

I had Both motors a 500w Bpm motor marked 250w with 36v 20a controller and I also had a Cube cx bike.The BPM doesent stand a chance at steep hills.And with a dongle I could have higher speed at some medium hills with high cadence than your Big bear would have top speed on the flat.

 

[Woosh]

The BPM doesent stand a chance at steep hills.And with a dongle I could have higher speed at some medium hills with high cadence than your Big bear would have top speed on the flat.

I can agree with you on that. The Big Bear has no load speed at 20mph, it is optimized to pull heavy load at 17mph, so can't match a CD bike with the same output.
However, I did hook the GSM CD motor to the bmsbattery kit, I reckon it would match the CX and more.