Killed 2 bafang SWX02 motors. Yes, two!!!

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woofnbike   10 mW

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Killed 2 bafang SWX02 motors. Yes, two!!!

Post by woofnbike » Apr 23 2021 3:43pm

well, i had one good scooter and one bad and then i managed to mess up even the good one. i need help. and fast, because i've got a thing like MS and these scooters are the only way my dog gets a walk.

i know both throttles/batteries/controllers are ok. it's the bafang SWX02 rear-hub motors, i am 99% sure. at least that's what the motor tester i got from amazon tells me.

Scooter 1 (S1), with tester. Spinning the wheel, all the phase lights come on at once -- in other words, not sequentially. Meanwhile, the blue and green hall-sensor lights do alternate but the yellow one just stays lit. Here's a vid of the action: https://youtu.be/b7z-e5Us7HY .

Scooter 2 (S2), with tester. Spinning the wheel, once again, all the lights come on at once. As to the halls, only the middle green light goes on and off. The blue light just stays lit, no movement. And the yellow one doesn't light up at all. (And S2 worked perfectly until i messed it up playing with the tester when i first got it.)

I'm really at wit's end here, esp since i know less than nothing about this kind of stuff. Any thoughts about what I might try next to get at least one of them working?

(I am going to put out a help-wanted call elsewhere, in case someone here lives in san diego and might be willing to lend me a hand. my dog bosco really needs his walks!)

thanks!
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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by amberwolf » Apr 23 2021 4:08pm

First, what specifically was done to or what happened to the systems between the time they worked, and the time they did not? This will help us help you find the root cause of the problem so it doesn't happen again.

More info below:
woofnbike wrote:
Apr 23 2021 3:43pm

Meanwhile, the blue and green hall-sensor lights do alternate but the yellow one just stays lit.
This usually means it is stuck on. That usually means it is damaged and needs to be replaced. They don't normally just die, so something else caused the failure.

Scooter 2 (S2), with tester. Spinning the wheel, once again, all the lights come on at once. As to the halls, only the middle green light goes on and off. The blue light just stays lit, no movement. And the yellow one doesn't light up at all. (And S2 worked perfectly until i messed it up playing with the tester when i first got it.)
Those two halls probably need to be replaced; one is probalby stuck on, and the other is no longer able to turn on. (though the wire could just be broken to the latter, or a connection problem somewhere between sensor and tester)

The most likely cause of the damage in that case might be accidentally connecting the halls (signals or power) to motor voltages, etc.

The halls work by grounding a voltage supplied by the controller (or tester in this case) when a magnet passes them. The output stage can only handle so much current and voltage, and if that's exceeded, it tends to cause the output stage to fail stuck on.

The typical type of hall used in these motors is the Honeywell SS411A. (the marking on them is likely to be a Chinese part, but it is likely operationally the same as SS411A).
https://www.mouser.com/ProductDetail/Ho ... iyguRdo%3D

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by woofnbike » Apr 23 2021 5:18pm

let's see ...

re S1: it was working fine, then one day it wouldn't go but i pushed forward where I was and then it ran again, for that day. increasingly, over a few days, it works less and less and then stopped.

with both scooters, if i turn the throttle, the wheel will often kick forward a tiny bit, hardly visible, then stop.

re S2: was again working fine, then i got my new tester. can't remember how i hooked it up but i may have had some wires crossing. in any event, that was that. freaked me right out, since if i'd just left it alone, id be in okay shape. but nooooo, i just had to see how a good motor responded to the tester. dummy.

attached is a pic of one of the motors as open as i've gotten it so far. any way to further test the halls? and how taxing a job do you think it'll be to take out the bad and put in the good?

btw/ thanks mucho for the speedy response!

btw pt 2 / do you think these halls will do the trick? they're SS41s: https://www.amazon.com/HONEYWELL-EFFECT ... 527&sr=8-2.
I can also get the SS41f pretty quickly on ebay ....
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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by amberwolf » Apr 23 2021 7:48pm

woofnbike wrote:
Apr 23 2021 5:18pm
re S1: it was working fine, then one day it wouldn't go but i pushed forward where I was and then it ran again, for that day. increasingly, over a few days, it works less and less and then stopped.

with both scooters, if i turn the throttle, the wheel will often kick forward a tiny bit, hardly visible, then stop.
Normal for a hall sensor failure, as the controller can't tell what position the motor is in, so it can't send the power in the right order to the phases to turn it correctly. Sometimes when only one sensor is bad, or has a connection problem, it may be able to be started by rolling forward a bit first and then starting, as you saw. Depends on how well the controller is designed to deal with the problem.
attached is a pic of one of the motors as open as i've gotten it so far. any way to further test the halls? and how taxing a job do you think it'll be to take out the bad and put in the good?
If you've got some experience soldering, it is not too difficult, but you have to unscrew the board they are mounted on, then lift it away from the motor without damaging any other wiring, and hold it in place with something ("helping hands" weighted clip unit is one of the easiest; there's a bunch of versions out there; this type you can often find at harbor freight or other local stores https://www.amazon.com/Weller-Helping-H ... B08FQB6XT3 ).

Then you need to carefully unsolder the failed hall(s) and replace them with new ones, making very sure you install them in the same orientation as the originals. There are bevelled edges on one side, and whichever way that faces is how you have to put the new ones in. Sometimes a motor has one in the middle facing the opposite way as the other two, and sometimes they're all the same direction. Yours are probably all the same direction, since they all have the pin 1 marking (square on the silkscreening) in the same place.

Sometimes they glue the sensors into the motor. If they did, it may be difficult to remove them without breaking them, and then you'll have to replace all three.


btw pt 2 / do you think these halls will do the trick? they're SS41s: https://www.amazon.com/HONEYWELL-EFFECT ... 527&sr=8-2.
I can also get the SS41f pretty quickly on ebay ....
Those 41 series need 4.5v minimum to operate; it's very common for controllers to put a diode in series with the 5v to the halls (to prevent damage to the controller's 5v in the event of a wire shorting event), and that takes the 5v down to around 4.3-4.5v, which means they may be at the bare edge of being able to work. They can work, but possibly not always reliably. The S variant is listed by Honeywell as a surface mount unit so it won't work for your application; you want just the plain SS41 or SS41L. The F version isn't listed on honeywell's datasheet, but SEC makes an F variant that comes in both surface mount (the kind you don't want) and SIP / flat-TO92 (the kind you need).

FWIW, there is a label on the board of your motor that actually says 41F on each sensor. So your motor may come with SS41F in there already.

The one by itself toward the axle is probably the same kind (to save money) used as a speed sensor (the white wire), but I can't read it's actual markings.

The 411 series only takes 3.6v, so it will work fine on the lower-than-5v supply from most controllers. Based on the Honeywell datasheet, you want either the SS411 or SS411L; others are the wrong shape/etc.
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motomech   1.21 GW

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by motomech » Apr 24 2021 9:07am

I recently ran my SWX02 on a sensorless controller, it ran fine;
https://www.pswpower.com/products/36v-4 ... -output-31
The KT890 would be the least expensive display that would work;
https://www.pswpower.com/products/24v-o ... e-parts-52
Takes a while to get them though, it was 14 days to arrive here in Tucson.
'11 Motobecane Fathom team, Bafang SWX02-13T, 14S (54V) LiPoly, 9-FET 17A controller. Schwalbe Marathon's, 24 to 25 MPH.
Hobie Passport Kayak w/ Watersnake 18# motor, 12S LiPoly (46V) to golf cart 12V converter, 4 mph

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by woofnbike » Apr 24 2021 9:52am

thanks, mototech. should those components turn bad, i'll know where to go. meanwhile, got a good source for these SWX02 motors? (see end of this note for details.)

amberwolf: think these would do? https://www.ebay.com/itm/114505778894?h ... SwDPtfpy~C . they are SS41F, id'd as TO-92-Flat-3 . couldn't find quick easy source for the others but these are in CA and could get to me pretty quick. don't know about my soldering skills these days, given various tremors and/or shakes, but me dog says to give it a try.

morning testing notes, based on this video: https://www.youtube.com/watch?v=w7ld-E1 ... bV&index=3.

using the china tester alone on S1, i get the same results as before. using a multimeter along w/ the tester, however, i get this, with incremental turns of the wheel: blue: 3.4v, green: 3.4v, yellow: 1.82v.

using the multimeter alone, with no turns of the wheel, i get the following, with the meter set to continuity (i think) as per the video near the 9 min mark:
-- with probes directly touching the circuit board, red to red 5v and black to the halls in turn, 1920 all around; and with red to the black ground and black probe to the halls: 700 all around.
-- with probes used on the wires that come out of the motor, the results are the same.

don't know what this means or if it changes anything but, well, there ya go. and assuming it's still the halls ... think those ebay ones will be okay?

meanwhile, i might as well go about trying to source at least one replacement motor. could you tell me what i'm looking for, exactly, given that it's for a scooter with a 20" wheel, disc brakes and no gears? see pix for details. BF SWX02 36V 350W (10) 20.

looking around myself, i get confused by the gearing business, cassette, non cassette, etc. i'm hoping i can find something that's pretty turnkey. and i guess i'd have to take it to the bikeshop to get someone to do the spokes and rim.

whew!

and thanks again for your help. yesterday, i was in total despair. today, i'm only halfway there.
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motomech   1.21 GW

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by motomech » Apr 24 2021 1:39pm

thanks, mototech. should those components turn bad, i'll know where to go. meanwhile, got a good source for these SWX02 motors? (see end of this note for details.)
You don't understand, a sensorless controller doesn't use the Hall sensors, it doesn't matter if one or more of the motor Hall sensors are bad. I've replaced Halls in the past on bad Ezee motors Grin sold me. It was tricky and the one I got to run lasted less than a year and then one failed again. BTW, Grin sells Hall sensors for that motor.
I've got an SWX02 10T (What we call a Jump motor since it was recycled from a Jump rental ebike). It's just the motor, not in a whl or anything. I'm not looking to sell it but I guess I could if you are stuck.
Still, I think the easiest way to get the system going again is to just use a sensorless controller (I have an extra one of those too).
Last edited by motomech on Apr 24 2021 5:30pm, edited 1 time in total.
'11 Motobecane Fathom team, Bafang SWX02-13T, 14S (54V) LiPoly, 9-FET 17A controller. Schwalbe Marathon's, 24 to 25 MPH.
Hobie Passport Kayak w/ Watersnake 18# motor, 12S LiPoly (46V) to golf cart 12V converter, 4 mph

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by markz » Apr 24 2021 2:37pm

Sensorless controllers are the way to go!
Then all you do is hook up the phase wires, and connect the Learn wires, usually white and the motor spins. You flick the throttle to change the direction of the wheel and you unplug the white wires. While you are at it you might as well buy 2 spare throttles from the same place you buy the controller from. My go to is Greentime EVFitting on Aliexpress
https://evfittinggreentime.aliexpress.com/store/313864

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by Manbeer » Apr 24 2021 3:39pm

Can he just get one of those jump wheels from Jag 35 and swap the guts into his wheel? Not sure of the spacing but that looks almost like a 100mm front hub. Granted it would be a different wind but it probably wouldn't make a terrible difference for walking the dog

edit: Never mind I thought those ones used an SWXO2? Looks like maybe not

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by amberwolf » Apr 24 2021 4:14pm

woofnbike wrote:
Apr 24 2021 9:52am
meanwhile, got a good source for these SWX02 motors?
See these threads:
viewtopic.php?f=2&t=110408
viewtopic.php?f=3&t=111160
They are front motors laced into 26" wheels, but if they are the same as the ones you have (since you don't have chains/etc on yours, they are probably front motors; if your dropouts are 100-110mm on the frame), then all you have to do ;) is unbolt the old and new motor internals from their casing (without unlacing the wheels), and swap the internals between the wheels. The entire core including the gears and clutch and everything usually just slide out of the case by putting the axle end on the non-open side down on the ground, and holding the tire/rim, and pushing down on that tire/rim to push the axle and motor up and out of the casing. It's typically pretty easy to do.

Some motors are bolted together at that other side, or have a circlip or some other fastener securing the axle on that side to the outside of the bearing, but the geared motors I've had are not made that way. (I have not yet opened up my motors from the above link, so I don't know if they are made this way or not).

amberwolf: think these would do? https://www.ebay.com/itm/114505778894?h ... SwDPtfpy~C . they are SS41F, id'd as TO-92-Flat-3 . couldn't find quick easy source for the others but these are in CA and could get to me pretty quick. don't know about my soldering skills these days, given various tremors and/or shakes, but me dog says to give it a try.
They look correct.

using the china tester alone on S1, i get the same results as before. using a multimeter along w/ the tester, however, i get this, with incremental turns of the wheel: blue: 3.4v, green: 3.4v, yellow: 1.82v.
If the sensors do not change in reading (toggling between some voltage nearer 5v than 0v, and some voltage nearer 0v than 5v) as you turn the wheel, with the meter's black lead on hall ground, and the meter's red lead on each hall signal in turn, then either the sensor is bad or there is no pullup connected to it's signal. (a motor hall only grounds an existing voltage, so without a pullup you don't get any voltage output from it).
using the multimeter alone, with no turns of the wheel, i get the following, with the meter set to continuity (i think) as per the video near the 9 min mark:
-- with probes directly touching the circuit board, red to red 5v and black to the halls in turn, 1920 all around; and with red to the black ground and black probe to the halls: 700 all around.
-- with probes used on the wires that come out of the motor, the results are the same.
To test the halls using continuity (rather than a voltage reading using pullup resistors on the hall signals and a voltage source, like the tester does), you must use the black lead of the meter on the hall ground, and the red meter lead on the hall signal, because the hall sensor grounds when active, and opens when inactive.

For a good hall, you will get OL on the screen when the hall is inactive, and you may get a beep or tone and a reading around 0.80 or similar when active. Some meters take a "long" time to respond so you may have to turn the wheel very slowly to see the response, with geared motor.

For a bad hall, you'll either get no change as the wheel turns, or you will get a very different reading for either active or inactive or both, vs the good halls.

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by motomech » Apr 24 2021 5:36pm

Some motors are bolted together at that other side, or have a circlip or some other fastener securing the axle on that side to the outside of the bearing, but the geared motors I've had are not made that way. (I have not yet opened up my motors from the above link, so I don't know if they are made this way or not).
Just remove the 6) cover screws (T20 security bit) and cover lifts off. A light tap on the other axle end and the complete core falls out.
Couldn't be simpler.
Slight interference fit on the bearings (as it should be), but no heat required on re-assembly, just gentle tapping around the boss.
Last edited by motomech on Apr 24 2021 5:50pm, edited 1 time in total.
'11 Motobecane Fathom team, Bafang SWX02-13T, 14S (54V) LiPoly, 9-FET 17A controller. Schwalbe Marathon's, 24 to 25 MPH.
Hobie Passport Kayak w/ Watersnake 18# motor, 12S LiPoly (46V) to golf cart 12V converter, 4 mph

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by motomech » Apr 24 2021 5:48pm

markz wrote:
Apr 24 2021 2:37pm
Sensorless controllers are the way to go!
Then all you do is hook up the phase wires, and connect the Learn wires, usually white and the motor spins. You flick the throttle to change the direction of the wheel and you unplug the white wires. While you are at it you might as well buy 2 spare throttles from the same place you buy the controller from. My go to is Greentime EVFitting on Aliexpress
https://evfittinggreentime.aliexpress.com/store/313864
I didn't have to connect any "learn" wire(s). Just matched the phase colors and it was a go.
The latest genaric sensorless controllers work much better than the first gen., like the old KU controllers from BMS Battery. No more does the rider need to get half a pedal in before the controller sync's-up. The only difference between a new "torque imitation" sensored square wave and the sensorless was I thought there was maybe a little more motor noise running it sensorless, but that's subjective.
The reason I went back to the sensored unit was because I like the KT810 LED display better than the KT890.
'11 Motobecane Fathom team, Bafang SWX02-13T, 14S (54V) LiPoly, 9-FET 17A controller. Schwalbe Marathon's, 24 to 25 MPH.
Hobie Passport Kayak w/ Watersnake 18# motor, 12S LiPoly (46V) to golf cart 12V converter, 4 mph

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by woofnbike » Apr 24 2021 7:27pm

i'll try to explain as best my brain will allow. when i got the S1 scooter, the main cable wires to the display/throttle were all fudged about and at one point, a wire came loose and the thing wouldn't run. took me a while to figure that out. but then it's just like i said: i rode the scooter, good weather only, though mostly in a fairly bumpy dog park, but never ever fast, and over the course of maybe 5 rides max it went from perfect to the state it's in now. i figured it had to be those wires, so i swiped what was on the other scooter and brought it over but it did no good.

at that point, S2 was still running just swell and i tried using its controller and throttle on S1, to no avail.

i agree, tho: the motor looks new. they came from a rental business that couldn't rent them anymore due to covid.

up until a few days ago, S2 was carrying me around just fine. but then i guess i crossed some wires while messing with the tester and that was that. i was using the old S1 throttle cable but i'd fixed it up and wasn't having any issues with it. i have tried the other cable with it, with no love.

i do wish i knew what's caused these issues because maybe i spend a good bit of money and they still don't run. or i kill the new stuff. argh!

here's what i think the appropriate greentime controller is: https://www.aliexpress.com/item/3278689 ... 4408VPGrZH. it's half the price of the PSWpower one (and shipping it cheaper too). but, motomech, is the geentime version the old style and i'd be better off with the PSWP one?

i'll prolly get a new display while i'm at it but do i need new displays and throttles to go with the hallfree controller?
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if you want more/different pix, just let me know. and thanks, all, for your help. it's well above and beyond what i was hoping for. bosco thanks you too!
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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by John in CR » Apr 25 2021 12:10am

Electrics don't like going very slow at low partial throttle, because they are very inefficient running like that and phase currents (the pulses going to the motor) spike sharply. When running inefficiently it turns much more juice from the battery into heat instead of work. More typically low partial throttle blows controllers, so since you did your own wiring you may have had what I call a "false positive" wiring combination...ie one that spins the wheel but isn't correct. A telltale sign is a slightly rough startup, but sine wave controllers can mask that.

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by woofnbike » Apr 25 2021 10:21am

well, that could be it -- i normally go only as fast as necessary to stay upright, maybe a lil faster, 4 - 5 mph. that said, i'm hardly ever out for more than 1/2 hr.

meanwhile, i'd love to place an order by tomorrow but i'm still not sure what exactly to get, ifn i'm going the sensorless controller route.

mototech -- if i go with your controller/display recommendations, i think i'll need to get a new throttle, too, since the current one is integrated with the display. can you suggest one, given that money is a consideration? i suppose i'll be buying two of everything, as well, so it's really going to add up, with shipping and all. would love to go with markz's controller thought but perhaps not if one has to deal with Learn wires, and i still wouldn't know what display/throttle to buy at greentime.

again, i so appreciate ya'lls help here.

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by woofnbike » Apr 25 2021 11:35am

well, i just found this on amazon: https://www.amazon.com/Opaltool-Brushle ... =8-39&th=1 .

reviews are okay and they say sensorless as well. for $20 with prime, i might as well try it ... assuming, of course, that it'll work with my existing display/throttle, which seems pretty generic. what do you think?
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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by motomech » Apr 25 2021 11:57am

OK, first off, I think we had a rare occurance where I posted and deleted at the same time you responded. Sorry, my bad as I thought my post sounded harsher than I intended.
John in CR has a point, sometimes when an electric motor is "lugged" down to a slow speed, the controller "sees" a condition where it tries to supply all the Amps it can and things start to melt. I've done it myself, but it always involves a hill. Well, we have what we have, so let's just try and get it running again and if we can, maybe Bosco can run faster:)
Let's take stock of what we know now, starting off w/ the motors;
However it happened, from the test results, it appears one or more Halls on BOTH motors are not working. That leaves two options;
1)Replace the Halls. I'm a little confused here, as I only see one here, not the 3 on a 120 degree spread I'm used to, but let's estimate $10 for the parts. Now do you have a soldering iron, solder and flux? Figure $15 for the lowest priced kit. Do you have experience soldering? Replacing Halls is not rocket science, but the space will be small and a steady hand is needed.
2)Or replace the controller with one known to work w/out Hall(s).
Well, since we are not exactly sure if your controller is ok, replacing the Hall(s)is no guarantee it's going to work and if you don't have those things I've listed above, you will be spending $25 to find out.
Now that we see the controller, it looks proprietary, for the scooter or the Jump bike I don't know. It's deffinately low power, but we can get close. As to your Ali-express suggestion, that controller might work, but did you look at the est. arrival date? June 1st. PSW Powwer would be half that. I would suggest this controller;
https://www.pswpower.com/products/24v-3 ... -output-32
and this display (required);
https://www.pswpower.com/products/24v-o ... e-parts-52
$40 total from a real ebike vendor that we have used and trust is better economey than Ali-Express I think.
The batt. wires should plug in.
You will have to cut the HiGo (9-pin) cable and connect the three phase wires. I think w/ a system so low power, you can use crimp connectors.
I confused, do you have a working throttle or not. If not, now is the time to get one. They are cheap enough and I can probably tell you what colors to connect. Even if you have to experiement, you will be relived to know you can't hurt anything trying different throttle wire combos.
'11 Motobecane Fathom team, Bafang SWX02-13T, 14S (54V) LiPoly, 9-FET 17A controller. Schwalbe Marathon's, 24 to 25 MPH.
Hobie Passport Kayak w/ Watersnake 18# motor, 12S LiPoly (46V) to golf cart 12V converter, 4 mph

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E-HP   100 MW

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by E-HP » Apr 25 2021 12:46pm

I'm trying to follow the thread, but not sure what happened between the first post, and the last thread, and the pics of the motor with the cover off. In your last thread, both bikes clearly had cast wheels. The smaller wheeled bike looked best for your needs, since it would allow riding at your slower pace. In this thread, the first pic shows the larger cast wheeled bike, but then your motor pics have a spoked wheel. Did the problem happen after a motor swap. Sorry, just trying to follow along.

EDIT: Nevermind, I see it's rear wheel drive.

EDIT2: I think I'm caught up. Both scooters were working, after a previous wiring repair to #1. Then #1 started having problems and stopped. You tried doing hall testing on both motors, and fried the sensors on #2, possibly by reverse polarity. Now both don't work, and you're replacing the hall sensors and controller. Is that the current stage? Are you repairing one or both at this point?

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by woofnbike » Apr 25 2021 1:29pm

man o man, even i'm confused at this point. i should have kept a diary of my various tries, flubs and failures. nothing to be done for it now.

e-hp: edit 2 is closest to it. i'd love to repair both right now but in the interest of cost savings, i think i'll just do one. am not going to replace the halls; instead, i'm going to get a sensorless controller.

mototech: yes, i will have to get a new throttle, if only because the current ones are all-in-one with the displays. maybe there's a cheaper throttle on amazon that'll do, saving me at least the additional shipping cost. know of any offhand?
so, if i get that PSW controller, then a new display is required. I believe that's what you're saying. Which means that the amazon controller i linked to won't do me any good with my current display/throttle combo. i went ahead and ordered it, thinking optimistically, but i still have time to cancel the order ... or wait, take possession, try the thing, hopefully not fry more bits and send it back if i do or it just doesn't work. but if what i've got now is clearly known not to work with it, then i'll just cancel the order and get what i need from PSW.

quick question about the display. the ad says: the KT-LED890 can not be setup by itself. You need to copy parameters from KT-LCD1 or from another KT-LED890.

is that something i have to worry about?

thanks for any further thoughts you and yall might have!!!!

p.s. you're right about the soldering biz. i have the stuff to do it with but not the skill nor the steady fingers.

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motomech   1.21 GW

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by motomech » Apr 25 2021 7:33pm

The amazon controller is not exactly right. Note it is rated 18 Amps and I think it might be too much for your application unless you want a scooter that wheelies. Almost all controllers are matched to their displays and don't interchange, but w/ this one, I don't see a connector for a display and I think you will have to wire in a 3-speed switch for speed limit and an off/on switch if you want those features.
Look, there's a reason I'm not telling you, "go order any controller off Amazon or Ebay or Alibaba. I've needed controllers in a hurry in the past and have looked, but to get one that ticked the right boxes, and that I had faith in, I have always had to go back to the biggies, BMS Batt. Elifebike, Psw Power, Grin, etc and just wait for it. But I guess that one will work if you wire in the switches.
The idea of buying the throttle now and adding it to the PSW P. order was to save on freight, not increase it.
There are throttles on Ebay
I need a break.
'11 Motobecane Fathom team, Bafang SWX02-13T, 14S (54V) LiPoly, 9-FET 17A controller. Schwalbe Marathon's, 24 to 25 MPH.
Hobie Passport Kayak w/ Watersnake 18# motor, 12S LiPoly (46V) to golf cart 12V converter, 4 mph

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by E-HP » Apr 25 2021 8:26pm

woofnbike wrote:
Apr 25 2021 1:29pm
i went ahead and ordered it, thinking optimistically, but i still have time to cancel the order ... or wait, take possession, try the thing, hopefully not fry more bits and send it back if i do or it just doesn't work.
Since none of those cheap controllers are programmable, one of the most important considerations when choosing a controller is the battery you have. You don't want to solve one problem at the cost of frying your battery. Any specs that you can share about your batteries?

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by woofnbike » Apr 25 2021 9:53pm

moto: so sorry to be trying, esp after all the help you've given. you're right. i'll get what i need from PSW -- that'd be the controller, the display, and a throttle. i'll go see what they have in the way of throttles and be done with it. thank you again.

E-HP -- all i know about the battery on this contraption is that it's 36v, 10A.
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woofnbike   10 mW

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by woofnbike » Apr 25 2021 10:06pm

oh for crap's sake. i was just about to add that controller to my shopping cart when i saw that the second one mototech suggested was for a 250W battery and my battery is 350W. but the 350W controller is rated at 17amps, and the 250W is at 15amps, while my battery is rated at 10amps. so maybe that's why the 250W makes sense. get those ratings closer so i don't kill myself doing unintentional wheelies. i dunno. i've got a headache. and a very grumpy dog.

and then i just saw that they're all sold out of the 250w controller. dang it all!

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by motomech » Apr 26 2021 2:13am

OK, here's one from PSW Power's ebay store;
https://www.ebay.com/itm/222373438917?h ... xyaTxTUWbp
Don't get hung-up on the 250 Watt or 350 Watt thing, this one is 12 Amp like your original.
Sensorless
810 display on / off & 3 - speed limiter
Gd. price
Only bad thing is time to get. I have bought from them before and it's always been two weeks.
I looked for one you can get sooner w/ all these things, but can't find.
Maybe one w/out display, but display is a better way to limit speed than wiring in a switch.
Anyhow, if you can wait, this is the best avail.
Don't see a reasonable price throtlle, ck Ebay
'11 Motobecane Fathom team, Bafang SWX02-13T, 14S (54V) LiPoly, 9-FET 17A controller. Schwalbe Marathon's, 24 to 25 MPH.
Hobie Passport Kayak w/ Watersnake 18# motor, 12S LiPoly (46V) to golf cart 12V converter, 4 mph

woofnbike   10 mW

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Re: Killed 2 bafang SWX02 motors. Yes, two!!!

Post by woofnbike » Apr 26 2021 8:07am

thank you for that. the order has been placed. whew. now i'll let you get some peace and quiet, while i go cancel my amazon order. and if this works out as expected, then i'll get another set for the second scooter and off bosco and i go, with you to triple- thank. muy bueno. onward! and thanks to everyone else who weighed in, too!

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