How fast was one ascending when the controller got hot ?

Very variable , but manged to keep it above 8. But these are long climbs on a warm day.

Start by checking that the motor connector is in all the way to the line.

First thing I did.

 

I'm thinking that, because the speed reading suddenly stopped working, that something in the controller has gone. It sounds like it is misfiring as the motor not deepened and gave more vibration.

Very variable , but manged to keep it above 8. But these are long climbs on a warm day.

 

First thing I did.

 

I'm thinking that, because the speed reading suddenly stopped working, that something in the controller has gone. It sounds like it is misfiring as the motor not deepened and gave more vibration.

The speed reading comes from the speed sensor. If there's no speed signal from it, or if you have P1=0, the controller will take the speed signal for the LCD from the motor halls, which is why you have to enter the number of magnets and reduction ration. In that condition the speed would show zero when free-wheeling. That wouldn't have any affect on the operation of the motor.

 

On my Q128, the speed sensor packed up quite early on, so I've always used an external wheel magnet type.

I have P1=128. Speed display did work but stopped mid ride. There is no speed sensor connected, never has been.

So, as you say, it must be getting the speed signal from the halls. As it was working fully but is not now (and no settings have been changed) would this indicate there's something faulty with the Halls?

Bike has had several hours to cool down now. I've just run it up and down the village (flat road) and everything was working OK, including the speed display.

I really am thinking it may be heat related.

Think I may need to get more ventilation which is difficult whilst also weatherproofing it.

I have P1=128. Speed display did work but stopped mid ride. There is no speed sensor connected, never has been.

So, as you say, it must be getting the speed signal from the halls. As it was working fully but is not now (and no settings have been changed) would this indicate there's something faulty with the Halls?

Q128 has an internal speed sensor, but maybe the magnet has come unglued.

Yesterdays ride involves climbing out of the valley I live in, going down into the next then climbing out of that before going down to the coast.

The second climb I noted as 1.6 miles from bottom to flat (ish) top. Variable gradient with the first 6-800 yards being around 1:6. The climb out from the coast (via less severe gradients) is a very long intial climb of around 4 miles. Very variable inclines so speed varying from 8 to around 12/13.

This is alot of slow speed climbing in level 5, trying to keep above 8mph.

So I decided to do some maths.

 

Controller is T09S set at 20A max.

Motor is 48v 328rpm running at 36v giving 246rpm.

Measured wheel radius is 13.25" giving 83.25" circumference.

So:

@246rpm this gives a motor top possible speed of 19mph

Therefore 16mph is .842 of top speed

10mph is only .526 of top speed

8mph is 0nly .421 of top speed.

 

So, do I have the wrong motor? From the maths and given the 16mph restriction, it seems it never gets near to magnetic saturation.

Given the long climbs that one has to do to get a decent length of ride around here, is the length of time spent in low back emf conditions just too much for the system? Too much heat being produced?

 

I'm starting to think I need a 201rpm 36v motor.

If the T09S got very hot ( too hot to hold or touch for more then a brief nano second) then one would say thermal cut out where mosfets reached their max op temp.

 

I had the same issue with T06S and why I opted to for the T09S and since not had the issue on the same rides.

My AKM128CST is 36/201 , I run it at both 36v & 44v .

Edited July 4, 2025Jul 4 by Nealh

Thanks Nealh, those are the lines I'm starting to think down.

At the moment operation is erratic. This morning I went to the next village shopping, about a 4 mile round trip.

It let me down badly crossing a main road at an offset cross. Approach to junction is downhill so no assist. Exit is up camber onto main road then up an off ramp. Pulled out onto main road - nothing- no assist, no throttle. Didn't kick in until I was onto the off ramp. Unpredictable and bloody dangerous.

Thanks Nealh, those are the lines I'm starting to think down.

At the moment operation is erratic. This morning I went to the next village shopping, about a 4 mile round trip.

It let me down badly crossing a main road at an offset cross. Approach to junction is downhill so no assist. Exit is up camber onto main road then up an off ramp. Pulled out onto main road - nothing- no assist, no throttle. Didn't kick in until I was onto the off ramp. Unpredictable and bloody dangerous.

How can it be overheating when up you are on a downhill with no power being supplied to the motor? I'm thinking it is some weird software glitch.

My thoughts exactly.

My thoughts exactly.

Software either works or not. It can't glitch. There are only two possibilities: 1. You have a connection fault; 2. Temperature is going too high.

 

Neal, what happens when the temperature goes too high? Does the LCD show anything?

 

My motor is faster than yours. I still stick to the 15 mph limit. I climb very long hills at 8 mph. Nothing has ever over-heated. Maybe your hills are steeper than mine. I'm roughly 95kg. How heavy are you?

 

Did you check that your phase wire bullets are all the way in and tight?

Edited July 4, 2025Jul 4 by saneagle

Software either works or not. It can't glitch.

I seem to remember Boeing having the odd one or two in the recent past

Software either works or not. It can't glitch. There are only two possibilities: 1. You have a connection fault; 2. Temperature is going too high.

 

Neal, what happens when the temperature goes too high? Does the LCD show anything?

 

My motor is faster than yours. I still stick to the 15 mph limit. I climb very long hills at 8 mph. Nothing has ever over-heated. Maybe your hills are steeper than mine. I'm roughly 95kg. How heavy are you?

 

Did you check that your phase wire bullets are all the way in and tight?

When the temperature goes too high on mine, (KT) the power stops completely or greatly reduces , the display looks normal

sorry for the diversion, [mention=3847]saneagle[/mention] this case is why I have not sold KT controllers and stick with Tongsheng, Bafang and Lishui. When you have the facilities to configure the controller to your own liking, you may run into complications like overheating, intermittent faults. I can't see that the extra sales of a £40 controller are worth the extra cost of support.

Bullets were the 2nd thing I checked.

When it wouldn't work (crossing the main road), there was nothing. Display was still on showing assist level but no mph.

Can only be the pas can't it? No pas, no assist or throttle. Pas is one piece so, apart from the plug at the controller, there's nothing I can check.

Neal, what maximum current do you have set?

sorry for the diversion, [mention=3847]saneagle[/mention] this case is why I have not sold KT controllers and stick with Tongsheng, Bafang and Lishui. When you have the facilities to configure the controller to your own liking, you may run into complications like overheating, intermittent faults. I can't see that the extra sales of a £40 controller are worth the extra cost of support.

Ouch ! Would have bought one of yours but you didn't want to supply without battery.

When the temperature goes too high on mine, (KT) the power stops completely or greatly reduces , the display looks normal

That's what happened yesterday, like it had gone into some sort of limp mode.

But how can it be overheating when it hasn't been doing any work? It's happening after a long downhill section with no assistance.

 

If someone would like to explain their thought process on how this is occuring I'm happy to reconsider.

I've only hit this problem going up very steep hills, slowly (<7 mph) in max assist level.

As explained above, there were some long climbs and it was during one of these that the cutout problem first occured.

I'm starting to think that cumulative heat has done some damage to the electronics. The intermittant nature is puzzling and would seem to point to a connection issue, but I can't find anything.

Bullets look and feel fine but I am thinking of soldering.

As explained above, there were some long climbs and it was during one of these that the cutout problem first occured.

I'm starting to think that cumulative heat has done some damage to the electronics. The intermittant nature is puzzling and would seem to point to a connection issue, but I can't find anything.

Bullets look and feel fine but I am thinking of soldering.

[mention=9614]Nealh[/mention] has said it happened to him and permanently damaged the controller

From memory as it has been over 6 years since when I had my thermal cut outs the display went blank so affected power supply . I remember having no warning or errors, just a sudden loss of power and display shutting down.

Following a cooling down period the display would switch on again and I was able to ride again obviously I has to watch speed on any further inclines soon after as they take a while to cool down really low.

Bullets were the 2nd thing I checked.

When it wouldn't work (crossing the main road), there was nothing. Display was still on showing assist level but no mph.

Can only be the pas can't it? No pas, no assist or throttle. Pas is one piece so, apart from the plug at the controller, there's nothing I can check.

Neal, what maximum current do you have set?

 

Ouch ! Would have bought one of yours but you didn't want to supply without battery.

 

I set current as max with any TS model so TS06 either 17a or 20a, TS09 22a or 25a.

Like the TS06 the 09 's come in 22a or 25a flavour.

Thanks Nealh, those are the lines I'm starting to think down.

At the moment operation is erratic. This morning I went to the next village shopping, about a 4 mile round trip.

It let me down badly crossing a main road at an offset cross. Approach to junction is downhill so no assist. Exit is up camber onto main road then up an off ramp. Pulled out onto main road - nothing- no assist, no throttle. Didn't kick in until I was onto the off ramp. Unpredictable and bloody dangerous.

 

It may be, one has a dodgy /intimitent controller ?

Apart from my one T06S that gave me heat issues I have never had another TS 0x issue in the 10 odd years I have been using them.

I tried to remedy the TS06 at the time with adding a larger heat sink to the main body (didn't work)next step was a pair of 5v PC fans attached to the heat sink to provide cooling via it 's own 4p1s power source ( still was great). So in the end simply ditched the set up for a TS09 and problem was solved.

 

Once a controller gets so hot like that , I'm fairly sure damage will have occurred somewhere on the PCB besides the mosfets so expect it doesn't take much for it to become flakey.

Brakes switches can cause issues sometimes , I remember my BBS01 being a right pain with two switches so took the front one off.

With KT I have never fitted brake switches because they are not required.

With my tiny G370 front hub motor I have only used it in PAS 2 with my TS09 even towing a 126+ kg load with my Carry Freedom trailer , albeit on fairly flat terrain the TS09 was no bother at very slow speeds.

 

Have you checked the hub motor for heat whilst the controller gets hot ?

 

Can you confirm the controller only gets hot on inclines ?

 

Also for P1 , one would think a P1 of 128 is quite low . I would think 168 - 224 woulkd be more the ideal P1 range.

With 16 motor pole magnets one would need a 8:1 internal motor gearing for P1 128.

A lowly set PI not only will give an incorrect odo reading but also may affect the pick up /syncing correctly of the motor.

 

328rpm I thought were 9.63 gearing so P1 154ish, I would have a little play around with P1 first.

Problem is is has never been clear cut if the gearing ratio's given are correct or not , all we know is they supply the AKM in various ratio's ranging ing from 9.63 - 13.2 . I seem to remember once seeing a 15.7 ratio quoted.

Edited July 4, 2025Jul 4 by Nealh