Possible controller overheated?

AxialFlux

Member
Hello all! Just did my third ebike build for my brother, and decided to do a 500w 48v geared hub motor kit for his fat tire bike. The install was easy, and after adjusting some settings, the bike was running great. He came over today to check it out, and we went riding around the neighborhood. He loved it!

Cut to a couple hours later, and he calls me from a state park near us with the bad news that the bike has lost all power. He is 5 miles into a trail using PAS 2 riding up an incline, and the power just shut off, neither PAS or the throttle was doing anything. The LCD (LCD3) was showing zero battery(see pic), when in fact the meter on the battery was still showing a full charge. I have him unzip the controller bag to check the connections, and he informs me that the controller is so hot he cannot touch it. I advise him to wait until it cools down, and try it again in hopes that some thermal shutoff has triggered, but it did not help. Once it did cool, he confirmed all connections were/are fine.

I am assuming something in the controller has burnt up, and the Amazon seller is sending me a new controller. However, I have never had this happen to either of my other bikes. One is a 500w 48v geared hub motor gravel bike, and the other is a 1000w hub motor 29" mountain bike. Both of these have been on trails very similar, if not worse than what he was on. In both of these bikes, I have the controllers in plastic controller cases, which I would assume would make them more likely to overheat that his in the little nylon pouch.

I guess my question is, how do I prevent this from happening again IF the new controller fixes everything? And also, am I correct in assuming the controller is shot? At first the Amazon seller was convinced that a new throttle and PAS sensor would fix it, and I had to sternly convince him that I really did not think that would help anything, haha.
 

Attachments

  • 1617147811756_6198254066_f272ca87.jpg
    1617147811756_6198254066_f272ca87.jpg
    272.5 KB · Views: 38
  • IMG_20210330_080548.jpg
    IMG_20210330_080548.jpg
    450.2 KB · Views: 41

theemartymac

Well-Known Member
So assuming you didn't just get a bum controller, we need to know which controller you are using, and it's amp rating. Also, what are the settings you input? It can be easy to burn out a controller with a couple of mistakes in the settings.

Also, was the rider burning the motor too hard? A fat bike on a good hill can overheat quicker than you might expect, and a 500w hub isn't that large to power a heavy bike and load. The geared hubs don't shed heat like DD's so they can get very hot inside without showing it in the case. As they get hot, they can draw more power from the controller and burn them out. Especially if it's a tiny under-spec'd controller insulated in a thick bag. Maybe try testing the other one in open air, and a little more thoroughly before you give him the bike back next time. if it's getting uncomfortable to the touch during slow speed crawls, long or steep climbs, or hard on-off acceleration cycles, you'll need to tame some settings.

I have a 750W geared hub bike, and I can overheat it and fault it out on 0.5km of steep climb if I don't keep my speed up and/or give it constant full beans on even mid PAS.
 

AxialFlux

Member
This is the controller specs, sorry that it isn't more clear, but that is taken from the Amazon listing. Looks like the voltage is 36/48v, rated current is 11a, max is 22a.

I don't think he was running the motor too hard, of course I wasn't there, so I can't be sure. He just said he was in PAS 2, and not using throttle only. I do plan on having him test the other one in open air, and having him monitor the temps. I suppose if it is still getting hot, I need to look at a controller that can handle more amps?

Far as the settings go, I assume this would limit the power so as to lower the amp draw?
 

Attachments

  • Screenshot 2021-03-31 075817.png
    Screenshot 2021-03-31 075817.png
    135.7 KB · Views: 40

JES2020

Active Member
So assuming you didn't just get a bum controller, we need to know which controller you are using, and it's amp rating. Also, what are the settings you input? It can be easy to burn out a controller with a couple of mistakes in the settings.

Also, was the rider burning the motor too hard? A fat bike on a good hill can overheat quicker than you might expect, and a 500w hub isn't that large to power a heavy bike and load. The geared hubs don't shed heat like DD's so they can get very hot inside without showing it in the case. As they get hot, they can draw more power from the controller and burn them out. Especially if it's a tiny under-spec'd controller insulated in a thick bag. Maybe try testing the other one in open air, and a little more thoroughly before you give him the bike back next time. if it's getting uncomfortable to the touch during slow speed crawls, long or steep climbs, or hard on-off acceleration cycles, you'll need to tame some settings.

I have a 750W geared hub bike, and I can overheat it and fault it out on 0.5km of steep climb if I don't keep my speed up and/or give it constant full beans on even mid PAS.
I am unclear about slow going uphill overheating the motor.
Is this still a concern if you are going up hill slowly at low throttle settings or helping by pedaling
PS when you say constant full beans, do you mean full throttle or pedaling hard?
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
For starters, get that controller out of the bag! That's a really bad plan.

The next question might be did he check the motor to see if it wasn't just as hot?

From there you need to know a few more things. The first might be was he riding it motorcycle style, or contributing a fair share pedaling?
 

JES2020

Active Member
Hello all! Just did my third ebike build for my brother, and decided to do a 500w 48v geared hub motor kit for his fat tire bike. The install was easy, and after adjusting some settings, the bike was running great. He came over today to check it out, and we went riding around the neighborhood. He loved it!

Cut to a couple hours later, and he calls me from a state park near us with the bad news that the bike has lost all power. He is 5 miles into a trail using PAS 2 riding up an incline, and the power just shut off, neither PAS or the throttle was doing anything. The LCD (LCD3) was showing zero battery(see pic), when in fact the meter on the battery was still showing a full charge. I have him unzip the controller bag to check the connections, and he informs me that the controller is so hot he cannot touch it. I advise him to wait until it cools down, and try it again in hopes that some thermal shutoff has triggered, but it did not help. Once it did cool, he confirmed all connections were/are fine.

I am assuming something in the controller has burnt up, and the Amazon seller is sending me a new controller. However, I have never had this happen to either of my other bikes. One is a 500w 48v geared hub motor gravel bike, and the other is a 1000w hub motor 29" mountain bike. Both of these have been on trails very similar, if not worse than what he was on. In both of these bikes, I have the controllers in plastic controller cases, which I would assume would make them more likely to overheat that his in the little nylon pouch.

I guess my question is, how do I prevent this from happening again IF the new controller fixes everything? And also, am I correct in assuming the controller is shot? At first the Amazon seller was convinced that a new throttle and PAS sensor would fix it, and I had to sternly convince him that I really did not think that would help anything, haha.
I was toying with the idea of cooling my geared hub with automatic trani fluid (ATF). There are some pretty good test results online (youtube). But now I find that with 3 amps over what the motor is rated I can get 38.6 MPH, I am not so worried about overheating, especially since I rarely go that fast, and when I do it's for short spurts.
There are some pretty nifty automobile thermometer out there that can monitor the controller, or if you want to disassemble the hub and test you nerve running a wire thru the axle, you can monitor the windings inside the motor.
Hello all! Just did my third ebike build for my brother, and decided to do a 500w 48v geared hub motor kit for his fat tire bike. The install was easy, and after adjusting some settings, the bike was running great. He came over today to check it out, and we went riding around the neighborhood. He loved it!

Cut to a couple hours later, and he calls me from a state park near us with the bad news that the bike has lost all power. He is 5 miles into a trail using PAS 2 riding up an incline, and the power just shut off, neither PAS or the throttle was doing anything. The LCD (LCD3) was showing zero battery(see pic), when in fact the meter on the battery was still showing a full charge. I have him unzip the controller bag to check the connections, and he informs me that the controller is so hot he cannot touch it. I advise him to wait until it cools down, and try it again in hopes that some thermal shutoff has triggered, but it did not help. Once it did cool, he confirmed all connections were/are fine.

I am assuming something in the controller has burnt up, and the Amazon seller is sending me a new controller. However, I have never had this happen to either of my other bikes. One is a 500w 48v geared hub motor gravel bike, and the other is a 1000w hub motor 29" mountain bike. Both of these have been on trails very similar, if not worse than what he was on. In both of these bikes, I have the controllers in plastic controller cases, which I would assume would make them more likely to overheat that his in the little nylon pouch.

I guess my question is, how do I prevent this from happening again IF the new controller fixes everything? And also, am I correct in assuming the controller is shot? At first the Amazon seller was convinced that a new throttle and PAS sensor would fix it, and I had to sternly convince him that I really did not think that would help anything, haha.
I was toying with this idea. I may try it when I have other things I want to do when the motor is disassemled, but I find I get more that enough power with a moded controller puting out just 3 amps above the motor rating (for short periods).


Also I would "attempt" to install one of these on the windings.(if I can thread a wire thru the axle).

 

JES2020

Active Member
I was toying with the idea of cooling my geared hub with automatic trani fluid (ATF). There are some pretty good test results online (youtube). But now I find that with 3 amps over what the motor is rated I can get 38.6 MPH, I am not so worried about overheating, especially since I rarely go that fast, and when I do it's for short spurts.
There are some pretty nifty automobile thermometer out there that can monitor the controller, or if you want to disassemble the hub and test you nerve running a wire thru the axle, you can monitor the windings inside the motor.

I was toying with this idea. I may try it when I have other things I want to do when the motor is disassemled, but I find I get more that enough power with a moded controller puting out just 3 amps above the motor rating (for short periods).


Also I would "attempt" to install one of these on the windings.(if I can thread a wire thru the axle).

Pardon the repetition...my computer posted before I was done and I didn't know it.
 

AxialFlux

Member
For starters, get that controller out of the bag! That's a really bad plan.

The next question might be did he check the motor to see if it wasn't just as hot?

From there you need to know a few more things. The first might be was he riding it motorcycle style, or contributing a fair share pedaling?
Yeah, I think getting it out of the bag is a good idea, although I'll have to figure out a mounting plan.

Not sure on the motor temps, but I do know he was pedaling and not just using throttle.
 

JES2020

Active Member
For starters, get that controller out of the bag! That's a really bad plan.

The next question might be did he check the motor to see if it wasn't just as hot?

From there you need to know a few more things. The first might be was he riding it motorcycle style, or contributing a fair share pedaling?
Al Could you answer these question of mine?:
I am unclear about slow going uphill overheating the motor.
Is this still a concern if you are going up hill slowly at low throttle settings or helping by pedaling?
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
It surely is a bum controller. A decent controller will cost 3 times the value of the controller shipped with the kit.
Then I've been using a bum controller the last 3 years or so to power my MAC 12t.
 

tomjasz

Well-Known Member
Then I've been using a bum controller the last 3 years or so to power my MAC 12t.
That's 1! Working phone and email support lines have revealed many failed cheap controllers. As long as you're happy all is well. ;) I prefer a Wide Operating Voltage Range and a Sinewave Controller.
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
Al Could you answer these question of mine?:
I am unclear about slow going uphill overheating the motor.
Is this still a concern if you are going up hill slowly at low throttle settings or helping by pedaling?
It's about how many watts it's pulling (going up that hill, or on a wide open run for that mater), and how long it's been pulling that many watts. You're fine pulling absolute max available power for a short sprint. Beyond a short sprint, there is concern about heat build up - in the motor and the controller to a lesser extent.

So to put that in practical terms, if this is a 500w motor we're talking about, in a perfect world it should be OK to run at 500w for miles. In the real world however, the geared hub (AND mid drive) motors are buried, where there's NO air circulation - and heat starts building faster than it can be dissipated. The Grin charts will show you that..... -Al
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
That's 1! Working phone and email support lines have revealed many failed cheap controllers. As long as you're happy all is well. ;) I prefer a Wide Operating Voltage Range and a Sinewave Controller.
Thomas, I would not throw KT controllers on the "cheap" pile. They not only have sine wave controllers available (most of them any more), most are set up with what they call "imitation torque control". That's "chinglish" for power based PAS (vs. speed based PAS) - which is a very desirable feature not available in many places. That, with the degree of user "configurable" parameters (WAY beyond wheel size and max speed for instance), make them pretty desirable. Then you can talk about the displays available for use ONLY with the KT controllers. They don't take a back seat to any other displays! If you get the chance, try one. If approached with an open mind, my bet is your opinion on them will change to something more favorable at minimum....

Then there's tha fact Bolton and a few others have done quite well with them....... -Al
 

AHicks

Well-Known Member
Region
USA
City
Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
All are not created equal in my limited experience with them. I'm thinking a $325 kit won't have a better version of their controllers. No? I can learn...and am listening!
OK, check these guys out. I've dealt with them a few times, so I trust them. They've been around a while, and have a pretty good reputation, but this is just one source. There are others on AMAZON and Ebay, selling out of China AND stateside......


Start with the controller of choice (no, that's not a misprint on the price!), then add whatever you want (no misprint on those prices either), and it will arrive with a wire end to match the controller. Makes building your own kit (if you have the need) pretty attractive......

I just did a brand new Espin Flow with this "kit". Purchased last fall at a huge discount (1100.). Went from an absolute POS controller, to one of the best available in my opinion, with a color display(!) very reasonably. Turned it into a pretty awesome little bike! A lot of our riding is in the hills, and the wife just got 60 miles on a charge where it was charged at 47v and brought back down to that same point (14ah battery).
 
Last edited:

JES2020

Active Member
It's about how many watts it's pulling (going up that hill, or on a wide open run for that mater), and how long it's been pulling that many watts. You're fine pulling absolute max available power for a short sprint. Beyond a short sprint, there is concern about heat build up - in the motor and the controller to a lesser extent.

So to put that in practical terms, if this is a 500w motor we're talking about, in a perfect world it should be OK to run at 500w for miles. In the real world however, the geared hub (AND mid drive) motors are buried, where there's NO air circulation - and heat starts building faster than it can be dissipated. The Grin charts will show you that..... -Al
I see, I was confused by some posts saying that going slow up hill overheats the motor (no matter what power setting you have). Obviously stalling out the motor will quickly overheat it. They just didn't post it that way.
 

JES2020

Active Member
Thomas, I would not throw KT controllers on the "cheap" pile. They not only have sine wave controllers available (most of them any more), most are set up with what they call "imitation torque control". That's "chinglish" for power based PAS (vs. speed based PAS) - which is a very desirable feature not available in many places. That, with the degree of user "configurable" parameters (WAY beyond wheel size and max speed for instance), make them pretty desirable. Then you can talk about the displays available for use ONLY with the KT controllers. They don't take a back seat to any other displays! If you get the chance, try one. If approached with an open mind, my bet is your opinion on them will change to something more favorable at minimum....

Then there's tha fact Bolton and a few others have done quite well with them....... -Al
I love my KT and the many options to make it "mine".