Controller shunt

7

70oldsracer

10 mW
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Jul 24, 2019
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I have a controller off of my son’s VIvi e-bike. I tried to shunt it and the controller stopped working. My son upgraded to a whole new set up and I was wondering if anyone on here could rebuild the controller so I can use it on another build. I bought all new mosfets for it, looking for someone to solder them in. I’m hoping that will fix the issue. Also wondering if maybe I shunt it wrong, too big of a piece of copper wire, too much solder? Maybe it can be shunted properly for a little more power. I’m attaching a pic of the controller and any help would be greatly appreciated.
 

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I don't know what power range you're looking for, but generic controllers are so cheap that I've never considered repairing one, let alone modifying one. The 18A ones I've been getting for the community bike shop cost us $14 including tax and shipping. The 26A ones I've been getting for my own use are still under $30 all in. I just checked eBay and found some new 40A controllers $35 from China and $50 from USA, shipping included.

I appreciate that you're trying to coax new life out of some old junk, but at the point it fails, in your situation I would cut my losses and start fresh with one that's rated for what I'm trying to do.

P.S. -
That controller needs a display to turn it on, or else you have to jumper the enable wires. Did you attach the original display when testing it after your shunt mod?
 
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Also wondering if maybe I shunt it wrong, too big of a piece of copper wire, too much solder?
Click to expand...

Without a pic of that mod, it'll be hard to tell.

I kinda agree that this mod seems largely pointless. Those controllers are already built with tight margins. Pushing them outside of already stretched design limits is a recipe for a quick buy of a new controller anyway, so why bother?
 
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bananu7 said:
Without a pic of that mod, it'll be hard to tell.

I kinda agree that this mod seems largely pointless. Those controllers are already built with tight margins. Pushing them outside of already stretched design limits is a recipe for a quick buy of a new controller anyway, so why bother?
Click to expand...
I guess you can say “live and learn” I unsolderd the wire already, so unfortunately there aren’t any pics to show you. I’ll pull the controller apart and I can send pics of where I soldered the wire. I’d replace the controller with another one with more amps, but I already bought a controller and it just doesn’t work with my setup. Can’t seem to find a controller that will work. Here is a pic of the controller I purchased that will not work with my parts.
 

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Chalo said:
I don't know what power range you're looking for, but generic controllers are so cheap that I've never considered repairing one, let alone modifying one. The 18A ones I've been getting for the community bike shop cost us $14 including tax and shipping. The 26A ones I've been getting for my own use are still under $30 all in. I just checked eBay and found some new 40A controllers $35 from China and $50 from USA, shipping included.

I appreciate that you're trying to coax new life out of some old junk, but at the point it fails, in your situation I would cut my losses and start fresh with one that's rated for what I'm trying to do.

P.S. -
That controller needs a display to turn it on, or else you have to jumper the enable wires. Did you attach the original display when testing it after your shunt mod?
Click to expand...
Like I just replied. I would buy a new controller if someone could point me in the right direction. The one I purchased from eBay doesn’t work with my parts. I did connect the display after I shunt the controller and everything turned on. It’s just that when my son gave it throttle, it took off with really nice torque, but lasted only a second and then stopped working. Don’t know if a controller with more amps that will work with my parts?
 
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E-HP said:
So since nothing is known about your build or what the controller will be connected to, or what your “parts” are, or your budget, is it OK to just suggest a list random controllers. I guess we know the KT brushless motor controller doesn’t work, so maybe a brushed motor controller?

Here’s one to try
Click to expand...
I apologize for not explaining it clearly. It’s a 48 volt 500 watt e-bike. This is the bike all the parts came off of, hoping this clears up any confusion. Looks like it’s a brushless motor.
viviebikes.com

VIVI F26FUL Long Range Ultimate Fat Tire Electric Bike UL2849 Certified

Get started on your all terrain adventure! The design of the VIVI F26FUL long range fat tire electric bike perfectly combines unparalleled adaptability to complex riding conditions with superior comfort.
viviebikes.com viviebikes.com
 
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That’s helpful. There’s really no reason why the new KT controller you purchased won’t work with your parts. It’s likely not plug and play, but who knows, maybe it is. I don’t know because I can’t see what the wiring or connectors look like on your bike parts. The controller would work, but you’d need to replace connectors. Do you have a multimeter and soldering iron?
If you want something that’s more plug and play, then we’d need to see what the controller will be connecting to.
 
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E-HP said:
That’s helpful. There’s really no reason why the new KT controller you purchased won’t work with your parts. It’s likely not plug and play, but who knows, maybe it is. I don’t know because I can’t see what the wiring or connectors look like on your bike parts. The controller would work, but you’d need to replace connectors. Do you have a multimeter and soldering iron?
If you want something that’s more plug and play, then we’d need to see what the controller will be connecting to.
Click to expand...
These are the wires coming off the original controller, the three pin yellow plug is for the pedal assist. The plug on the left goes to the motor and the other one goes to the harness. The plugs on the motor and harness are the male versions of those two plugs in the pic.
 

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So the other end of the bike harness splits to connect to throttle and display (not sure what etc means)? Can you confirm? Also, the motor and PAS connectors are compatible with the new controller connectors? Can you confirm?
To set expectations, if the bike has a display, it won’t be compatible with the new KT controller. If you need a display, then be best way to ensure compatibility is to buy the controller and display as a set.
It’s possible to run without a display, but the pin out on the controller’s 8 pin harness needs to be figured out first.
Given the above, how do you want proceed? Also, you didn’t mention if you have tools (multimeter, soldering iron or crimpers, etc.).
 
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Etc. is short for ectetera. So the other end of the harness splits to the display, throttle, brakes, light switch and light. As far as the connections from the KT controller being compatible, the one for the motor is correct, but the KT controller is only an 8 pin and the harness is 9 pin. They will plug in, but not sure if it’s compatible. As far as proceeding, I have no problem either using the KT controller if I can or buying a controller with a display and throttle, whichever seems to be the easiest. As far as tools, I have everything, digital multi meter, solder gun, cutters, crimpers, pretty much everything I will need.
 
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From what I’ve seen, a KT display will work with a KT controller as long as the controller supports a display, but it’s not guaranteed. There are KT experts on this forum, so maybe they’ll chime in.
Support for lights is sketchy with many controllers, and for the KTs, the circuit doesn’t output enough power for lights, but only enough to trigger a relay for lights. In my opinion, it’s easier to work on light separately and adding a small buck converter to reduce the voltage to what your lights require. You may want to pursue that after getting the bike running. I’ve been working on a lighting section in the newbie faq in my signature, but it’s not ready yet. There’s probably some posts on the forum regarding lights, since it seems to come up every now and then.
The next step would be to check the connectors on the other end of your harness, to see what the throttle and brake connectors look like. It’s probably easiest to replace your harness with a KT version below, since you’ll only need to figure out how to connect the brakes and throttle which may be plug and play if the connectors match up. Don’t buy anything yet, until someone chimes in on the display compatibility.

Edit: there is a kits if KT displays and hyperlinks in my faq if you want to see what you prefer. Most have the same menu structure for setting them up. Some of the smaller models may have fewer features.
 
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Not sure have to get to your faq. Also, I’m not limited to using the KT controller I have. I’d be willing to buy a whole new kit, controller, display, throttle and brakes if necessary, as long as it will plug into my motor. I’d like something with a little more amps if that will give it a little boost and not cause any issues
 
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I've got several of this same exact KT 22A controller running my ebikes.

The 9 pin motor connector fits everything I've seen. I thought the 8 pin handlebar harness was also made to some standard, as I've bought 4-n-1 cables that work perfectly,

Did you buy a harness? This one should work with a KT,

If you're feeling adventurous, you can start the KT controller without a display, If throttle/PAS are connected, they should work.
 
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docw009 said:
I've got several of this same exact KT 22A controller running my ebikes.

The 9 pin motor connector fits everything I've seen. I thought the 8 pin handlebar harness was also made to some standard, as I've bought 4-n-1 cables that work perfectly,

Did you buy a harness? This one should work with a KT,

If you're feeling adventurous, you can start the KT controller without a display, If throttle/PAS are connected, they should work.
Click to expand...
I bought this cable, it’s not available right now.
 

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This is the pin out for a KT 4n1 Harness with the two pin red brake connectors..There is a center pin in some controllers, used for a light on a 5n1 harness.

Shows the output from the controller, as well as the cable.

A throttle would connect to Ground, plus the two throttle pins.
KT 4N1.jpg
The display uses the green connector and five pins.

You can check your harness for the same pinout to the disp[ay,


Ju;et_5.jpg
 
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So my display has the same Julet 5 pin connector as in your pic. My 8 pin harness looks exactly the same too. Everything should be plug and play except the Pas. The 3 pin plug from the bike is a female and so is the one from the controller. I purchased a male to male Julet 3 pin cable so I can connect them. I’ll give it a try later today, thanks.
 

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What display are you using though? Only a KT display works with a KT controller. Other displays may be able to power up the controller, but they can't change PAS levels or read the speed, Throttle and a basic PAS often work though, unless the foreign display gets upset that it cannot understand the data from the KT controller and shuts down,
 
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