Need New Controller for Customized Sondors Dirt Machine

The Panda

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I own a 2014 Sondors ebike. Custom 36-volt battery. BaFang 350 watt motor. After market controller (KT36 36V/48V 20A). When I bought a new 36 volt battery last year. It worked so well, it cooked the controller, after about a month of riding in sand/dirt.

I need a beefier controller. Probably 22A will do it. However, I have been unable to find one with the same number/type of connectors or the correct number of cables. All of my connectors are Julet, except of course the battery connectors. All I need, aside from pos-neg battery wires/connectors are:

  • A 9-(large) pin BaFang motor cable/connector:
  • Two 2-pin wires/connectors for the brakes;
  • A 6-pin wire/connector for the throttle (my Sondors throttle has a battery level indicator) and
  • A 3-pin wire/connector for the PAS.


It’s probably too much to expect that I’ll find a controller with the correct set of wires and connectors, but I could buy connectors and a crimper, if I could just find a controller with the various wires I need, which are identified, so I know which is which. I wouldn’t mind trying a different set up, such as a stand alone throttle, combined with a display. However, I have not been able to find a controller online which identifies the individual purposes of the various wires/connectors it features. I need help finding a controller which will work with my existing components.

P.S. I don’t understand why I have electricity to the disc brakes.
 
Electrobikeworld (dotcom) sells KT controllers specifically for Sondors Original fatties like yours. The one you want is the 25a controller. The 35a controller uses a motor connector that is meant for the big 750w motor. The EBW controllers will for example have the almost-unique black HIGO connector for the throttle. Also IIRC the PAS connection is the typical yellow HIGO except its gender is reversed, which was done to keep people from plugging in a Bafang throttle to that connection by mistake.

Unless something has changed you will not find controllers with Sondors-compatible plugs anywhere else besides Sondors.

I still buy them from that seller for other bike projects as I have Sondors parts still in my parts buckets so for me they are plug/play still.
 
Electrobikeworld (dotcom) sells KT controllers specifically for Sondors Original fatties like yours. The one you want is the 25a controller. The 35a controller uses a motor connector that is meant for the big 750w motor. The EBW controllers will for example have the almost-unique black HIGO connector for the throttle. Also IIRC the PAS connection is the typical yellow HIGO except its gender is reversed, which was done to keep people from plugging in a Bafang throttle to that connection by mistake.

Unless something has changed you will not find controllers with Sondors-compatible plugs anywhere else besides Sondors.

I still buy them from that seller for other bike projects as I have Sondors parts still in my parts buckets so for me they are plug/play still.
Thank you! Just ordered the controller. What a great site! Refrained from ordering the display, but may do that. Why does the controller send power to the brakes?
 
Why does the controller send power to the brakes?
It doesn't. It takes the brake controller cutoff signal and uses that to turn the motor power off if the brake levers are engaged. The brake cutoff circuit on Sondors and all Bafang-compatible systems is what is known as "Normally Open". When you depress the lever, it closes the circuit and the motor power is cut off for as long as the circuit is closed. (Thats why ebike brakes of the type that work with your controller are known as "NO" or "closers" or if buying Maguras from a German bike shop where they are cheapest: "Schliessers" (or more properly, "Schließers").

The reason I get into that is to explain the types of brakes you want to buy if you go there. I use Magura MT5e's which work without adapters with the Sondors KT controllers because they use the red HIGO plugs rather than the normal yellow ones.
 
Bought a 25A controller from Electrobike world. Didn't work. They told me i needed their display to complete the circuit, so I bought that. I hooked everything up and took a ride. Everything worked for about 10 minutes before I heard a loud squawking. I'm fairly sure that it is
coming from the controller, rather from the motor. The 20A controller I was using when I got the new battery I'm currently using lasted about a month, prior to the bike starting to make the same noise, which got progressively worse, until the bike began jerking on takeoff and the controller began to get so hot I quit using it. Electrobike world's controller has not gotten that hot yet, but it was between warm and hot, i'm fairly sure it will, if i keep using it.

Emailed Electrobike world the above info. Here's what i got: "The controller is all digital inside and has no moving parts. You might be over stressing yourself electrical system which is making the controller overheat. We recommend you tune down the power output via the display by going into the setting mode and change the C5 to 6. Are you sure the noise is not coming from the motor? The controller has no moving parts so we do not know how it can make any noise. If you hear like a metal scratching noise from take off and it gradually goes away, that is the sign your motor magnets are loose inside and needs to be replaced soon."

My bike is eight years old, but has not been used very much during that time. However, it was used vigorously during the last approximately 50 miles I rode it (i.e. riding in sand, while riding uphill, with a new 36V/22A battery, etc...). Would it be typical for a Bafang 350 watt motor, or the magnets inside it, to wear out under these circumstances?

Any ideas? Please advise. Thank you!
 
I have probably a half-dozen of those KT 25a controllers and I always buy from ElectroBikeWorld. Never had an issue. They work with generic KT displays so if you had a Sondors KT display (It is branded with 'Sondors' on the front), then it for sure would not work because Sondors contracted with KT to use custom protocols, so you would have to buy displays from them. Or alternatively if you had a more recent Sondors bike, those displays are not meant to work with KT controllers at all as Sondors stopped using KT entirely a few years ago.

If you have an Original with one of the old plastic-cased 350w single-speed motors then thats probably old enough to have a generic KT display.

I have never heard of any noise coming from the controller. And the C5=6 thing ... well I guess try it and see what happens but I can't see how that could be more than a band-aid to cover up something else. After all your battery is only 36v.

The older Bafang 350w motors on Sondors Originals (plastic case and single-speed, right? 16T cog in the back?) did in fact have occasional instances of the magnets coming loose. The noise is awful and only happens at initial acceleration, from what I have heard. What EBW is telling you is consistent with that magnet problem. Its sort of up to you to decide if that sound matches what they are saying. Its sort of like the motor having bolts grinding around inside and catching on stuff.

The motor magnets coming loose is one of those things that can happen without warning. Its not something wearing out. Its occasional poor assembly (insufficient glue) finally catching up to you. There is a set procedure for fixing it that involves numbering the magnets, taking them all out, putting them back in again in the same order, one at a time with better glue. I would join the SonDors Owners Group on Facebook and ask about this and hopefully someone will chime in with a tutorial. I have seen it but I have never had to do it myself.
 
I have probably a half-dozen of those KT 25a controllers and I always buy from ElectroBikeWorld. Never had an issue. They work with generic KT displays so if you had a Sondors KT display (It is branded with 'Sondors' on the front), then it for sure would not work because Sondors contracted with KT to use custom protocols, so you would have to buy displays from them. Or alternatively if you had a more recent Sondors bike, those displays are not meant to work with KT controllers at all as Sondors stopped using KT entirely a few years ago.

If you have an Original with one of the old plastic-cased 350w single-speed motors then thats probably old enough to have a generic KT display.

I have never heard of any noise coming from the controller. And the C5=6 thing ... well I guess try it and see what happens but I can't see how that could be more than a band-aid to cover up something else. After all your battery is only 36v.

The older Bafang 350w motors on Sondors Originals (plastic case and single-speed, right? 16T cog in the back?) did in fact have occasional instances of the magnets coming loose. The noise is awful and only happens at initial acceleration, from what I have heard. What EBW is telling you is consistent with that magnet problem. Its sort of up to you to decide if that sound matches what they are saying. Its sort of like the motor having bolts grinding around inside and catching on stuff.

The motor magnets coming loose is one of those things that can happen without warning. Its not something wearing out. Its occasional poor assembly (insufficient glue) finally catching up to you. There is a set procedure for fixing it that involves numbering the magnets, taking them all out, putting them back in again in the same order, one at a time with better glue. I would join the SonDors Owners Group on Facebook and ask about this and hopefully someone will chime in with a tutorial. I have seen it but I have never had to do it myself.
Thank you! you are correct. My Sondors is a single speed. Electrobikeworld has a Bafang 500W hub motor that is made for conversions. Looks like it's narrower than my motor, and perhaps made to the same size dropout. It would probably work great with the 25A controller and the display i just bought from them. Do people convert the old single speeds into multi speeds? Looks like this motor might be made for that. It sure would be a great upgrade for my bike.
 
Forget about that 500w motor. Thats a G020 and is a totally different animal. Yours is a G060.350. Looks like EBW has a solution with a non-Bafang motor. Read the description.

Do people convert the old single speeds into multi speeds?
I did with my 350W Sondors Original fattie. I used a 750w motor and get this... your dropout widths are quite a bit narrower thanks to that single speed setup. IIRC its something weird like 165mm. So to do the upgrade you will have to spread your chainstays. This is not a trivial operation and you really want to think hard about doing that. The same issue will be there for a 500w motor.

Its going to be nowhere near as simple as when I did mine in early 2017. The current Bafang motors have different plug connectors, so just for starters you will need the adapters only EBW sells and I think thats another 40 bucks right there.

Here's a pic of the 'tool' I made to spread the stays. Its allthread, some bolts and washers. The center widget is used with a plumb line to help ensure you are spreading the stays evenly one side vs. the other. I used a string and a bolt not a proper plumb line. To spread a steel frame (make sure you do NOT have one of the alloy ones) you will want to go too far out, then let it spring back, which it will do naturally. I cannot emphasize enough how there is a risk here of destroying your frame. I was spreading only enough to continue to use a singlespeed cog, but with a spacer behind it. These old frames are generally not capable of taking on a cassette motor version that is 190mm wide.

I did all this back in 2017. Not sure I would be messing with it in 2023. Thats an old bike now.

20170307_204714.jpg
 
Thank you! Wondering if there is a reason why you don't like the Bafang 500w motor, other than that it's not as powerful as the Bafang 750w. I have already purchased and used the 25A controller and the display that goes with it, tboth of which would work with the 500. Don't want to change horses now and have to buy the 35A, and probably another display to go with it. Seems like going with the 750W motor would make the project more expensive and much more complicated (having to spread the chainstays). The diagrams on the ElectrobikeWorld pages show dimensions, and show the OLD dimension for the 500 at 135mm and the 750 at 175mm. I think the OLD dimension shown is the usable axle length/chainstay width. Seems like I might be able to convert the bike to multispeed much easier and cheaper with the 500. You're right, the bike is getting a bit long in the tooth, but it works great and I'm not inclined to spend big bucks to get a newer one. All the more reason to do the simpler, less expensive converson, unless it's not going to work, or even just not work well. What do you think? Please let me know. Thanks again.
 
Thank you! Wondering if there is a reason why you don't like the Bafang 500w motor, other than that it's not as powerful as the Bafang 750w.
Because its the wrong motor. Physically it is significantly different (its much smaller) and will not fit. I'm referring to the one sold on EBW.

I have already purchased and used the 25A controller and the display that goes with it, tboth of which would work with the 500. Don't want to change horses now and have to buy the 35A, and probably another display to go with it. Seems like going with the 750W motor would make the project more expensive and much more complicated (having to spread the chainstays).
The thing with the Sondors upgrades (I am an admin on the Sondors FB group and have been around the platform for many years) was that the various wattages of the G060 motor were drop-in compatible. That is because they are all G060 motors. The 250w motor is just the 350w motor with '250' on the outside. The 500w looks to be the same as the 350 but is reported to have more windings. The 750w motors used to be dramatically different in physical size but they still fit inside of the G060 casing (Bafang has changed the internals of the current 750 so they now are much smaller). So you could take a G060.350 and drop in a G060.750 motor and it fit like a glove. A G020 can't do that.

If you want to go somewhere else and buy a G060.500 then it will work. But EBW doesn't sell that.

The diagrams on the ElectrobikeWorld pages show dimensions, and show the OLD dimension for the 500 at 135mm and the 750 at 175mm. I think the OLD dimension shown is the usable axle length/chainstay width. Seems like I might be able to convert the bike to multispeed much easier and cheaper with the 500.
You're not reading it right :)

If you want I can sit a G020 beside a G060 - I have a spare G060 in the garage and my Bullitt uses the G020 on the front wheel. And once you see them you'll say "oh ok that'll never work in a million years."
 
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