KT Controller, Smoke Leakage

M

MattZ

100 W
Joined
Jul 14, 2021
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101
Apparently these things aren't sealed very well, all the smoke leaked out of mine yesterday. Less than 100 miles on the bike, very frustrating. I can't find a replacement controller that I can get in less than a month.
I have a couple questions:
20210904_173621.jpg
20210904_170256.jpg
Is this repairable? It looks like a couple MOSFETS burned up.

Second question - I can't find these transistors with less than a 1 month delivery date either. They're Toshiba K150E09NE transistors. I'm trying to find a comparable transistor but fear I'm getting in over my head. Specs are slightly different and I assume they all matter.
If the controller is fixable, can someone direct me to a comparable transistor?
 
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Who really knows if its repairable or not, doubt you have the trouble shooting skills to probe upstream and downstream for damaged components to replace beside the obvious black smudge.

This is why you skip the displayed controllers and go with sensorless generic controllers or at least have a spare for cases like yours. Best bet is to find a sensorless controller that is nearby and hopefully they ship quick, maybe Amazon has 2-day shipping or next day shipping but it all depends on your necessity or urgency in getting back riding again.

You could just replace everything in the area, if you can see the label on the part but those small surface mount components are hard to replace and mount.
 
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AHicks said:
Do you know what caused this, or are you just assuming it was a defective
Click to expand...

No, I'm not assuming it's defective. I'm assuming I made a poor choice in choosing a bike/battery/motor combination. It seems like a 29" bike with a 2000w hub motor and 52v battery can't handle my 240lbs on a fairly slight hill. The motor cut out, controller felt hot, I shut it off for a bit till it felt warm. When I turned on the battery the smoke got out.
I'd been real happy with it on level ground.
 
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E-HP said:
Is this the same bike with the noisy motor?
Click to expand...

Of course not! It's the quiet bike. Even more quiet now. The noisy bike is still noisy, but still going strong. I have a new controller coming for that one although both the replacement and original are lower wattage, 30A max vs 40 on the cooked one. I'm guessing 30A would have more smoke waiting to get out.
 
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y MattZ » Sep 05 2021 12:13pm

AHicks wrote: ↑Sep 05 2021 12:00pm
Do you know what caused this, or are you just assuming it was a defective
Click to expand...
No, I'm not assuming it's defective. I'm assuming I made a poor choice in choosing a bike/battery/motor combination. It seems like a 29" bike with a 2000w hub motor and 52v battery can't handle my 240lbs on a fairly slight hill. The motor cut out, controller felt hot, I shut it off for a bit till it felt warm. When I turned on the battery the smoke got out.
I'd been real happy with it on level ground.
Click to expand...

Welcome to the club 200+lbs. My first build thought about Dual motors for the hills. Their are other options. Now worry about frame strength. Use a little bigger controller and FF in the motor.
 
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markz said:
Who really knows if its repairable or not, doubt you have the trouble shooting skills to probe upstream and downstream for damaged components to replace beside the obvious black smudge.

This is why you skip the displayed controllers and go with sensorless generic controllers or at least have a spare for cases like yours. Best bet is to find a sensorless controller that is nearby and hopefully they ship quick, maybe Amazon has 2-day shipping or next day shipping but it all depends on your necessity or urgency in getting back riding again.

You could just replace everything in the area, if you can see the label on the part but those small surface mount components are hard to replace and mount.
Click to expand...
I'm new to ebikes but have been fixing electronics for decades going back to when mainframes were repaired using wire wrap tools. But that's board-level stuff, not components, and I don't have (or want) a scope and likely can't solder those tiny SMT devices without destroying them. Plus it's that many more parts to find and try to get in a reasonable time.
I went with the same brand controller on both bikes I built to avoid having to figure out different settings and quirks, plus the display helps with the learning curve. But your suggestion makes perfect sense. I'll look for something I can get fast to hold me over.
 
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ZeroEm said:
y MattZ » Sep 05 2021 12:13pm

AHicks wrote: ↑Sep 05 2021 12:00pm
Do you know what caused this, or are you just assuming it was a defective
Click to expand...
No, I'm not assuming it's defective. I'm assuming I made a poor choice in choosing a bike/battery/motor combination. It seems like a 29" bike with a 2000w hub motor and 52v battery can't handle my 240lbs on a fairly slight hill. The motor cut out, controller felt hot, I shut it off for a bit till it felt warm. When I turned on the battery the smoke got out.
I'd been real happy with it on level ground.
Click to expand...

Welcome to the club 200+lbs. My first build thought about Dual motors for the hills. Their are other options. Now worry about frame strength. Use a little bigger controller and FF in the motor.
Click to expand...

I looked at dual motors briefly but figured that would kill range. So you think a little bigger controller will help...
I'm looking at them on Amazon but sellers aren't real clear on amperage, in many cases you can't tell if they're referring to rated amps or max amps. I suspect a higher rated controller will find the next weak link in the chain but if it's unusable it might as well burn up. What's FF?

I may go back to square 1 and start over. While sitting on the side of the road a couple came by on Aventon bikes. They're much lower powered but they went right up that hill no problem. The guy said it climbed pretty much anything. I prefer to build but I'm thinking a geared hub motor on a 26" fat tire bike might work better for me. I don't need to go real fast, 30 does the trick. Not sure if they go that fast though, and anything over 750w seems hard to find.
 
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by MattZ » Sep 05 2021 2:13pm

I looked at dual motors briefly but figured that would kill range. So you think a little bigger controller will help...
I'm looking at them on Amazon but sellers aren't real clear on amperage, in many cases you can't tell if they're referring to rated amps or max amps. I suspect a higher rated controller will find the next weak link in the chain but if it's unusable it might as well burn up. What's FF?

I may go back to square 1 and start over. While sitting on the side of the road a couple came by on Aventon bikes. They're much lower powered but they went right up that hill no problem. The guy said it climbed pretty much anything. I prefer to build but I'm thinking a geared hub motor on a 26" fat tire bike might work better for me. I don't need to go real fast, 30 does the trick. Not sure if they go that fast though, and anything over 750w seems hard to find.
Click to expand...

FF is Statorade Ferrofluid for Cooling Direct Drive Hub Motors. click on the link to find out more, they explain it better than I can.

You have figured out "next weak link in the chain". Welcome to eBikes we are always looking to fix our weakest parts. I like to over build a little to extend the life and OP like to push the limits.

You could had a weak controller but if your going to buy a new one then upgrade a bit and don't max it out. One thing to watch for is heat. If over heating then let it cool off. This goes for motors and batteries as well as controllers.

Motors run cooler when not lugging or running below 50% of max speed, this draws a lot of amps. Some people like the mid drives to use the bike gearing to pull hills. With DD motors get one that operates in your riding range. You balance motor size and voltage, Kv and wheel size.

The bigger guys here try to build bikes from a different point of view. We want strong wheels, plenty of torque to get moving, which is built for lower speeds. Big motors in little wheels will do the trick.

I'm just filling up the page now. :lol:

I was suggesting to get a 35A controller and run it at 30A. I don't know your motor but adding a coolant to the motor will let you run it a little harder with out over heating it. Then when you break it again can upgrade again. If you get the right setup and learn your bike it will last you many years. I worry about humidity eating and rusting away at my trike. :roll:
 
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ZeroEm said:
by MattZ » Sep 05 2021 2:13pm

I looked at dual motors briefly but figured that would kill range. So you think a little bigger controller will help...
I'm looking at them on Amazon but sellers aren't real clear on amperage, in many cases you can't tell if they're referring to rated amps or max amps. I suspect a higher rated controller will find the next weak link in the chain but if it's unusable it might as well burn up. What's FF?

I may go back to square 1 and start over. While sitting on the side of the road a couple came by on Aventon bikes. They're much lower powered but they went right up that hill no problem. The guy said it climbed pretty much anything. I prefer to build but I'm thinking a geared hub motor on a 26" fat tire bike might work better for me. I don't need to go real fast, 30 does the trick. Not sure if they go that fast though, and anything over 750w seems hard to find.
Click to expand...

FF is Statorade Ferrofluid for Cooling Direct Drive Hub Motors. click on the link to find out more, they explain it better than I can.

You have figured out "next weak link in the chain". Welcome to eBikes we are always looking to fix our weakest parts. I like to over build a little to extend the life and OP like to push the limits.

You could had a weak controller but if your going to buy a new one then upgrade a bit and don't max it out. One thing to watch for is heat. If over heating then let it cool off. This goes for motors and batteries as well as controllers.

Motors run cooler when not lugging or running below 50% of max speed, this draws a lot of amps. Some people like the mid drives to use the bike gearing to pull hills. With DD motors get one that operates in your riding range. You balance motor size and voltage, Kv and wheel size.

The bigger guys here try to build bikes from a different point of view. We want strong wheels, plenty of torque to get moving, which is built for lower speeds. Big motors in little wheels will do the trick.

I'm just filling up the page now. :lol:

I was suggesting to get a 35A controller and run it at 30A. I don't know your motor but adding a coolant to the motor will let you run it a little harder with out over heating it. Then when you break it again can upgrade again. If you get the right setup and learn your bike it will last you many years. I worry about humidity eating and rusting away at my trike. :roll:
Click to expand...

Oh statorade, yes I read about that, just didn't put 2 and 2 together with FF. I looked at mid drives but considered them too complicated for my leisurely putting along. I like tinkering around but still looking for the payoff at the end of the tinkering.
I'm sure I burned up the controller by putting along yesterday, uphill, on a gravel road. But there's a hill at the end of my street, it's not very big, maybe 75 yards long. The motor's cut out every time I go up it, but the bike flies on level ground. That's why I'm thinking geared hub motor and slightly smaller wheels - simple and more torque. At any rate I'll get this going again and figure out the next step. Or I should say get it going, figure out the noise on the other bike, then figure out the next step.
I ended up ordering a Sabvoton 45A max controller, so a little bigger. Maybe more durable but not looking forward to figuring out their settings, they look more complex. Didn't like the reviews of the ones on Amazon I could get in a couple days so I'll be patient for once. The burnt controller was 40A max but I don't think it was too close to that when it cooked, the display said 1800w at the time which should only be 30 amps.
 
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Don't kill your battery, pulling to many amps. Had a discussion a while back about steep grades. May need to slow down to your peddle speed and help the motor and don't power up the hill. 10-15 mph is a good speed to pull hills. but I don't have the long steep hills here so I could be full of it.

If your bike is faster than you need some get a lower Kv motor. You can get more torque per amp so you can run a smaller controller. Does not make the motor run cooler.
 
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On my KT controller I added thermal paste on the back of the mosfets, and then the back of the mica insulator strip under them; as the heat path otherwise is pretty terrible

Presumably if one of these mosfets overheats the rds increases, which overheats it more, until you have thermal runaway in very short succession
 
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If that controller is stored in a bag, you're very likely going to let the smoke out of the next one as well. They need to be out where air can circulate around them.

Geared hubs will climb hills on much less power than that required for direct drives.
Mid drives will climb even better.

Been here....
6'2" 315 lbs.....
Built my first bike with a 1500w direct drive, and found it gutless for my purposes. Swapped the direct drive hub for a MAC 12t geared hub, running that motor off the same 35a KT controller, with no other changes, and never looked back. Awesome combo......
 
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I find it better to run more controller than you think that you need. This way the controller isn't terribly stressed when asked to do things like ride up inclines. If it's programmable all the better, as you can dial it back to suit your needs without ever really maxing it out. Just make sure your battery is up to the challenge.
 
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Spent a couple hours yesterday deciding on that Sabvoton controller and got an email from the seller this morning saying they've discovered their entire stock is defective, has to go back to the manufacturer, and they don't know when they'll get more. All the different US sellers of this controller on ebay seem to be the same guy in Chino, CA. Looks like I'll have to find a different one elsewhere.
Heard back from the seller of the burnt controller. They'll send a replacement but their CA warehouse is closed till 9/11 for the holiday. Happy Labor Week I guess.
This one on Amazon looks like the next likely prospect https://www.amazon.com/Cozyel-Electric-Bicycle-Brushless-Controller/dp/B07MS143GY/
AHicks said:
If that controller is stored in a bag, you're very likely going to let the smoke out of the next one as well. They need to be out where air can circulate around them.

Geared hubs will climb hills on much less power than that required for direct drives.
Mid drives will climb even better.

Been here....
6'2" 315 lbs.....
Built my first bike with a 1500w direct drive, and found it gutless for my purposes. Swapped the direct drive hub for a MAC 12t geared hub, running that motor off the same 35a KT controller, with no other changes, and never looked back. Awesome combo......
Click to expand...
The controller was out in the open. I knew better than putting it in a box and don't like the look of bags. The MAC 12t sounds like a winner, I'll look into it. I see that brand mentioned here a lot.
It would be nice if you could just get a motor laced on a rim without buying a whole kit or buying a motor and rim separately and going down that rabbit hole.
ZeroEm said:
Don't kill your battery, pulling to many amps. Had a discussion a while back about steep grades. May need to slow down to your peddle speed and help the motor and don't power up the hill. 10-15 mph is a good speed to pull hills. but I don't have the long steep hills here so I could be full of it.

If your bike is faster than you need some get a lower Kv motor. You can get more torque per amp so you can run a smaller controller. Does not make the motor run cooler.
Click to expand...
I have to worry about the battery too? I'm starting to feel like i built a WMD instead of a bike.
 
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Don't want to scare you off of ebikes. Just learn (specs) what your battery can do. Then you can decide how to you use it.

i'm guessing your battery is only rated for + or -20a. Not saying it won't do more, just shortens it life. When I seen you looking at 45a controllers was thinking it was over kill. Your last control was maybe big enough but defected.

Don't know anything about "Cozyel 48V/72V 2000w controller.

As the experts here what controller they would recommend.

I know what would work for me but your not me. 35a controller just an example. Grin cost more but I trust them and they back there products. Have 20a and two 40a controllers from them.

Was reading on the KT controllers guess they are low cost but would not own one. you started talking about 45amp controller don't think you need anything like that unless up grading your battery and motor. I just figured that with ff you could put maybe 1500w for a short periods of time. 48V X 30a = 1,440w just short of it. 48 X 35a = 1,680s so I figured a 35a controller would be plenty. That should stress your battery and get the motor hot.

Run your bike within it's limits if it's not enough plan on your next build or ebike. Most of us here are never happy. Of course I am. That is why i'm building another ebike.
 
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52V 35A is plenty for 375lbs and short steep hills
However I'd like a few extra amps and watts for the longer steep hills when my drive train is dropping chain when tensioned due to crank wobble. My guess for me is 48V/52V and 50A, Grintech and EM3EV sells 40A(cont.) bms batteries, Luna 50A(cont.), UPP got a wide variety up to 50A(cont.), OSN has even more variety.
 
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markz said:
52V 35A is plenty for 375lbs and short steep hills
However I'd like a few extra amps and watts for the longer steep hills when my drive train is dropping chain when tensioned due to crank wobble. My guess for me is 48V/52V and 50A, Grintech and EM3EV sells 40A(cont.) bms batteries, Luna 50A(cont.), UPP got a wide variety up to 50A(cont.), OSN has even more variety.
Click to expand...
Based on that the bike shouldn't have noticed I was even on it. I have an UPP 52v, 20AH battery that says it's good for a 40A max constant discharge current, according to the listing. The motor's a 2000w DD, sold as a kit with that KT 40A controller. The listing called it a 40A controller, however the label on it says rated current 20A, max current 40A. I suspect that controller is too wimpy for the motor/battery/29" wheel combination. When the controller took a smoke break the motor and battery were barely warm.
ZeroEm said:
Don't want to scare you off of ebikes. Just learn (specs) what your battery can do. Then you can decide how to you use it.

i'm guessing your battery is only rated for + or -20a. Not saying it won't do more, just shortens it life. When I seen you looking at 45a controllers was thinking it was over kill. Your last control was maybe big enough but defected.

Don't know anything about "Cozyel 48V/72V 2000w controller.

As the experts here what controller they would recommend.

I know what would work for me but your not me. 35a controller just an example. Grin cost more but I trust them and they back there products. Have 20a and two 40a controllers from them.

Was reading on the KT controllers guess they are low cost but would not own one. you started talking about 45amp controller don't think you need anything like that unless up grading your battery and motor. I just figured that with ff you could put maybe 1500w for a short periods of time. 48V X 30a = 1,440w just short of it. 48 X 35a = 1,680s so I figured a 35a controller would be plenty. That should stress your battery and get the motor hot.

Run your bike within it's limits if it's not enough plan on your next build or ebike. Most of us here are never happy. Of course I am. That is why i'm building another ebike.
Click to expand...

I'm sure ebikes are like any other pursuit, there's always something faster, quicker, shinier. Unfortunately I'm the one that always wants it cheaper too, which rarely works out.
Nah, I'm not scared off ebikes but my wallet's getting pretty nervous.
I'm not looking for a forever controller yet, just one that I can get quickly to get some use out of the bike in the meantime and keep around for a spare later.
That Grin controller looks real nice, it's small too and only 7 bucks more than the Sabvoton that didn't come through. I read a lot of good things about them, they seem very popular. That's probably the direction I'll go. Thanks for the link.
The motor's rated at 2000w (so they say) so a 35A controller and 52v battery would have me at 1820w which should be fine, on paper anyway but who knows how much of those specs are wishful thinking.
 
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MattZ said:
That Grin controller looks real nice, it's small too and only 7 bucks more than the Sabvoton that didn't come through. I read a lot of good things about them, they seem very popular. That's probably the direction I'll go.
Click to expand...

The Grin units are nice, but can't be programmed. You get what you get, so any functionality/flexibility would come from adding a Cycle Analyst; so think a little more than $7 more, if you need any type of control.
 
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Regarding the Grin controllers, it uses the CA3 display. They're super capable as far as what they're capable of, but quite large as compared to others that display much more information. Bottom line, IMHO, the display is badly outdated (like out of the 60's and 70's level technology). When they get around to updating it, I'll likely get real interested in their GMAC geared rear hub - which is born from the MAC series of geared hubs.
 
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Yeah I've been reading up on their website and think that CA3 takes the Grin controller out of the running. It's a fairly new product using ancient technology, and expensive. I'm sure I'll need to mess with settings and can't do it without the CA3. Plus I put a lot of time and effort in running wires neatly to the controller, lengthening, shortening, soldering, crimping, heat shrinking, etc. Looking at their diagrams for CA3 everything other than phase and hall wires need to run to the handlebar. What were they serving in the meeting when they came up with that idea? They say it's to simplify things but I think it does the opposite. Might be OK for a new build but makes a retrofit a nightmare.
 
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I was making assumptions from the 20a/40a controller. the grin controller was just an example and its to small for what you need.
They are right can not program my controller it's the 40a and use the CA3 to control everything.

You have one on the way so all you need is a cheap backup. If you get a different controller you will need to change all the wiring connections, then change them back. Unless you put on connections like your current controller. just a thought.
 
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