@saneagle if I got a 36v 201rpm akm-128cst and ran it at 48v, and set the controller to 18 amps max, would you think that is likely to be ok ?
Help! My next project
- Thread starter Benjahmin
- Start date
If changing settings doesn't work, reduce motor wheel size to 24" for a bit more torque?
Well that took some time - doesn't it always? Because I've been using MP tyres for the last 12 years, the glue in the puncture outfit I had had gone solid. Result was a 28 mile round trip to the bike shop to get patches and spare tube. Plus side is that they had some no glue self stick patches, seem to work well.
Might do but it would also mean the cut off operating at a lower actual speed unless I increase the max speed which would defeat the object of trying to build a fully legal bike - aaarghhh !
Can't KT controllers calculate speed of a 24" motored wheel?
As an aside, your 36V batteries would power a fully unlocked UART BBS01B (if current limit can be raised to 20A = 720W) converted bike up those hills just fine, gearing permitting. Trouble is, the UART controller's current limit could be locked and all new BBS01B kits for sale appear to be Can Bus, which can't be customised much... but there are UART controllers available to buy which fit BBS01B motors - whether or not they're current limit locked is anyone's guess, unfortunately. Bafang has ruined things for hill climbers.
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OK, the consistency eliminates some possible causes. Not the throttle, not the PAS, definitely the algorithm, which might respond to settings, although I can't help there.
If this is not normal for a KT setup, perhaps someone with greater experience is able to shed light.
I wonder if the use of the 328rpm motor in a 700c? wheel is affecting the algorithm? It will hit 25km/h way below 328rpm, doesn't often get above half it's intended operating speed, although 36V vs 48V also makes a difference.
I wonder are you using an older square wave controller rather than the more modern sine wave controller. There has been reports on this forum of difficulties with AKM motors on square wave controllers that were solved by changing to sine wave controllers. e.g.
www.pedelecs.co.uk
www.pedelecs.co.uk
AKM100
We own three 20" bikes with the Q100H 260 rpm motors from BMS battery, All powered with 20A KT 6-FET controllers (two are sinewave), I built a fourth one this year, using an AKM100 from topbikekit..I pulled out an old BMS Battery P06 17A square wave controller to run it, but it would stall on...
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Help! - Controller for AKM75 motor
Hi, I have looked at several threads regarding this issue but my motor doesn't match the current spec on AKM own website as that indicates the motor cable exiting through the shaft. Mine has the cable coming out of the side of the axle. The forum threads all say the motor is sensorless but my...
www.pedelecs.co.uk
To catch up C4 was set at3 already.
With the wheel size thing, somebody's going to have to help me out here 'cos I'm not great at maths. The motor would develop more torque in a 24" but would it do that if I told it it was in a 24 when actually in a 700c? Also I'm trying to keep it legal so need to keep the indicated maximum speed as 15.5.
The irony here that as the max wattage comes up it's hitting maximum speed so, obviously, ramps down.
The controller is a sine wave 9 mosfet.
With the wheel size thing, somebody's going to have to help me out here 'cos I'm not great at maths. The motor would develop more torque in a 24" but would it do that if I told it it was in a 24 when actually in a 700c? Also I'm trying to keep it legal so need to keep the indicated maximum speed as 15.5.
This is what I'm wondering. Certainly at low speeds the motor doesn't sound very happy but that would be 6 and below. Could it be that the low revs feedback to the controller (I assume there is such a thing) prevents higher current feed to prevent heat build up?
The irony here that as the max wattage comes up it's hitting maximum speed so, obviously, ramps down.
The controller is a sine wave 9 mosfet.
That's perfect 260 rpm to get good power and efficiency at 15 mph.
The controller and motor can't change anything from the wheel size setting. That setting only effects the speed display. Set the wheel size to whatever you have. You set the cut-off speed to 25km/hr, and if the motor doesn't cut at that speed, change the P1 setting proportionally.
It would be nice if the algorithm had adjustable power ramp up, or ramped up power faster for larger wheels, and slower for smaller wheels. If your battery is capable of higher continuous current discharge, buy a more powerful controller? Or would shunting the controller be a good idea? Building the motor into a 24" wheel would give you more torque, but then your pedals would be closer to the road... unless you changed the fork and installed a larger front wheel, and if that didn't raise them enough, also fit shorter cranks.
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Having fixed a second puncture I took the bike on a longer run on Sunday.
Really it wants to do a minimum of 14mph. The wattage seems to be ramping up quicker now on the throttle, does it have a learning function because I haven't changed anything?.
However the pickup from going downhill (zero assist) to uphill full power is still slow. The hill climbing 'grunt' is less than the old Ezee. When hills start to level out it picks up smoothly and easily, resulting in the power being turned down. The up and down buttons are getting a lot of use.
Solo riding pretty much at the cutoff is fine - on good roads. On the rutted, muddy and generally more technical back roads, however, it's too fast. Also when riding with the wife on her Big Bear, she only will ride at a stately 10-12mph, meaning that even in my level 1 on the flat I'm leaving her behind. On hills she will sail past me on level 5.
From the sound of the motor it really doesn't like sub 10mph speeds.
I think running this 48v 328rpm motor at 36v in a big wheel, and then wanting/needing to cycle at low speeds is putting it smack into inefficient hell.
The big plastic controller box is getting warm on hills. There is some airspace in there but no ventilation. Wondering if I should compromise weather proofing for ventilation?
It really does look like I've built a bike that would be a great commuter for someone in the flatlands. Good surfaces, cycletracks and the need to be somewhere at legal speed with the minimum of sweat is where this bikes at.
I might consider a different motor once I've fully got the measure of this one.
Really it wants to do a minimum of 14mph. The wattage seems to be ramping up quicker now on the throttle, does it have a learning function because I haven't changed anything?.
However the pickup from going downhill (zero assist) to uphill full power is still slow. The hill climbing 'grunt' is less than the old Ezee. When hills start to level out it picks up smoothly and easily, resulting in the power being turned down. The up and down buttons are getting a lot of use.
Solo riding pretty much at the cutoff is fine - on good roads. On the rutted, muddy and generally more technical back roads, however, it's too fast. Also when riding with the wife on her Big Bear, she only will ride at a stately 10-12mph, meaning that even in my level 1 on the flat I'm leaving her behind. On hills she will sail past me on level 5.
From the sound of the motor it really doesn't like sub 10mph speeds.
I think running this 48v 328rpm motor at 36v in a big wheel, and then wanting/needing to cycle at low speeds is putting it smack into inefficient hell.
The big plastic controller box is getting warm on hills. There is some airspace in there but no ventilation. Wondering if I should compromise weather proofing for ventilation?
It really does look like I've built a bike that would be a great commuter for someone in the flatlands. Good surfaces, cycletracks and the need to be somewhere at legal speed with the minimum of sweat is where this bikes at.
I might consider a different motor once I've fully got the measure of this one.
Something is wrong with your settings. When you're on level 1, it should give about 60w, which is not enough to want to do a minimum of 14 mph everywhere. How many watts are actually showing on the LCD, when it's like that?
It's hovering around 80w, and that speed would be on a rare flat smooth road. Slightest of inclines speed go down.
I'll try and get them when it's finished charging.
But you said 14 mph everywhere! 80w is hardly enough to move the bike without help from your pedalling. I find it difficult to understand what problem you're experiencing. Your wife has speed control, so on level 2 or whatever, her bike gives full power up to 10-12 mph, then cuts out, so she maintains that speed up and down hills, except when freewheeling is faster. If you want to match her speed, you can re-set the speed limit on yours to 12 mph. If you do it after switching on, but don't save it, it will only maintain it for that journey. When you switch off and on again, it'll revert to 15.5 mph or whatever you have it set to. That will solve the difference in speed when riding with her.
Your controller can also be set to speed control with P3=0, but I think that also limits the throttle speed to the same as the pedal assist, so you can't use it as a power boost.
You mentioned that you press the up and down buttons a lot. That's completely unnecessary. Use the throttle. I have LCD4 with impossible to work buttons. I select level 2 for normal low power riding, and whenever I need more power for climbing a hill or going a bit faster, I press and hold the throttle lever. That's very quick and efficient. Pressing up and down buttons is old school, not for us cool kids.
Here's the settings
P1 128
P2 1
P3 1
P4 1
P5 13
C1 07
C2 0
C3 8
C4 3
C5 09
C6 3
C7 0
C8 0
C9 0
C10 n
C11 0
C12 4
C13 0
C14 2
Pas settings 1 80w ish
2 160 ish
3 280 ish
4 380 ish
5 720 ish
P1 128
P2 1
P3 1
P4 1
P5 13
C1 07
C2 0
C3 8
C4 3
C5 09
C6 3
C7 0
C8 0
C9 0
C10 n
C11 0
C12 4
C13 0
C14 2
Pas settings 1 80w ish
2 160 ish
3 280 ish
4 380 ish
5 720 ish
Definitely got gremlins in the system !
Went to my favourite seaside cafe today, lovely Tuscan fish stew.
Around a 12 mile ride to get there, lots of ups and downs. On the long descent into the village I noticed that, suddenly, there was no mph reading when not pedalling, when back brake (brake switch) was operated or when assist was set to zero. It had been there before, didn't think too much of it. Thought I might have to look at the settings.
After me lunch, it's a long variable incline climb to get out. Using levels 5,4 and 3. After around 3 miles the motor note changed, became 'buzzier' and gutless. First thought was motor connector. Up to the line, looked fine but took it apart anyway. No sign of any heat discolouration, so put it back together. Next thought, bullet connectors. Took the top off the controller box (TS09), to find controller was hot. Checked bullets, seemed fine. Took out the spare cable entry seal plugs to give some ventilation. Let the controller cool before carrying on.
All seemed good for the next 4-5 miles, some up but mostly down into the next valley, although still no speed reading when no power. At the end of another long descent there's about a mile of flatish before the start of the longest most brutal climb. As I approached the steep bit I went to level 5. Again motor note changed, stopped almost immediately.
Motor and controller were slightly warm. Sat down for about half an hour but it did not reset.
Had to phone the wife van rescue service.
Given the no speed reading and subsequent motor lack of guts and vibration, I'm starting to think the controller may be damaged.
Topbikekit did caution me that hooking the 800w 128 to a T09 was risky. They said a T012 was needed.
So what tests can I do here?
Went to my favourite seaside cafe today, lovely Tuscan fish stew.
Around a 12 mile ride to get there, lots of ups and downs. On the long descent into the village I noticed that, suddenly, there was no mph reading when not pedalling, when back brake (brake switch) was operated or when assist was set to zero. It had been there before, didn't think too much of it. Thought I might have to look at the settings.
After me lunch, it's a long variable incline climb to get out. Using levels 5,4 and 3. After around 3 miles the motor note changed, became 'buzzier' and gutless. First thought was motor connector. Up to the line, looked fine but took it apart anyway. No sign of any heat discolouration, so put it back together. Next thought, bullet connectors. Took the top off the controller box (TS09), to find controller was hot. Checked bullets, seemed fine. Took out the spare cable entry seal plugs to give some ventilation. Let the controller cool before carrying on.
All seemed good for the next 4-5 miles, some up but mostly down into the next valley, although still no speed reading when no power. At the end of another long descent there's about a mile of flatish before the start of the longest most brutal climb. As I approached the steep bit I went to level 5. Again motor note changed, stopped almost immediately.
Motor and controller were slightly warm. Sat down for about half an hour but it did not reset.
Had to phone the wife van rescue service.
Given the no speed reading and subsequent motor lack of guts and vibration, I'm starting to think the controller may be damaged.
Topbikekit did caution me that hooking the 800w 128 to a T09 was risky. They said a T012 was needed.
So what tests can I do here?
I ran my 328 rpm Q128 at 48v with a T06S for 14 years without any problems. They're probaly thinking of 200kg Americans riding without pedalling after shunt-modding their T09S. I now run it with a 22A 6 MOSFET KT controller, though not used it enough enough to say that it wouldn't overheat in adverse conditions because I've been using myother bike since.
The size or power of the motor has little affect on a controller over-heating. The power is regulated to the same by the controller. Only the speed of the motor needs to be considered. If you have one that's too fast for the speed you do, there isn't sufficient back emf to reduce the current from the controller, so the controller can give max current all the time.
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