AFAIK this 12FET is from the generation just prior to what they sell now. It hasn't yet been opened or programmed, etc., so it just has whatever the default settings they ship with.
It's from this post:
http://www.endless-sphere.com/forums/viewtopic.php?p=747654#p747654
I mentioned this problem (at some length) in my CrazyBike2 build/evolution thread, here:
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=779515
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=781325
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=820114
Other mentions are here:
http://www.endless-sphere.com/forums/viewtopic.php?p=747862#p747862
At one point I mistakenly thought the CA was causing the problems:
http://www.endless-sphere.com/forums/viewtopic.php?p=748492#p748492
but I was very wrong. I don't know why I didn't have problems at that time, but did before and later.
http://www.endless-sphere.com/forums/viewtopic.php?p=748896#p748896
The basic issue is that regardless of method used to set a constant throttle voltage input directly to the 12FET's throttle connection, and regardless of which motor is being controlled by the 12FET, speed does not remain remotely constant even on level ground with no wind. Speed decreases by at least 1MPH, then increases by at least 1-2MPH, and cycles intermittently (not on a specific time or frequency), over several seconds to nearly a minute (varies).
It *will not* simply let me ride at a constant or even near-constant speed, unlike any other controller I've ever used.
AFAICT using a meter, no voltage variation from the throttle itself occurs while it's set at any particular point, so it's not being commanded from the throttle itself--it's something in how the controller works.
The throttle is run direct, not thru a Cycle Analyst. The only CA connection to the controller I had (which I don't now) was for the speedo sense wire and ground.
I can see the power dropping dramatically, but not completely (despite what I posted in the above links), when the controller rolls back output. If I am at say 500W battery draw, it'll drop to 200W suddenly, until the speed drops far enough, and hten it will surge back to well above 500W (maybe 800-900W, depending on conditions at the time) till it reaches it's overspeed, then it will roll back, and cycle like that.
It doesn't go to the same speed, either under or over, each time, but rather oscillates around and each peak may get higher and higher successively, until at some point it reverses the trend. Same for rollback--it may drop to lower and lower speeds, until at some point it reverse the trend. But the trend is just a trend--it will sometimes still peak lower somehwere during a rising trend, etc.
Fixes tried so far, with identical results for each, were:
--Zombiess Throttle Tamer, to try to smooth out possible throttle voltage variations (even though I dind't see any variations, it dind't mean they weren't there, perhaps).
--Gripping the bar and the thumb throttle so tightly it hurt, to guarantee that my fingers weren't moving the throttle and causing it to happen.
--Tightening the grip against the throttle body hard enough for friction to hold the throttle in one physical position unless I drag it back to wehre it was (defeating it's internal spring, effectively).
--Uisng a switch to flip over from thumb throttle's signal line to a resistive divider instead, to input a specific voltage to hold a speed.
--Using a potentiometer as voltage-divided throttle.
--Using a different throttle, on hte left bar, wiht my left hand instead of right.
More specific behavior, to edit (for clarity and updated info) and summarize from the first linked post:
When using this 12FET to control the HSR3548 in 20" wheel on the rear, I put throttle at WOT from a stop, and it accelerates as desired (with or without using *both* front and rear for the first few seconds to get going quicker, with front 9C/6FET on a separate throttle), all the way up to my normal riding "top speed", which is just shy of 20MPH, exactly as I want. (top speed of the system is probably a lot higher than that, but I don't use it under any normal conditions).
Then it creeps up to say, 20.4MPH, which I could live with--I don't think the police would care about half a MPH; my speedo in the CA probably isn't even accurate to that since it's just set for basic diameter of a 20" tire. But as soon as it reaches that, maybe a second or two later, power cuts way way down, perhaps in half.
Then it goes back up just a little in power but not enough to hold the speed, and coasts down to as low as 18.5MPH.
Then it applies another long burst of power, this time going up to as high as 20.9MPH.
Then power cuts again, and eventually cycles back on and goes even higher the third time, up to 21.5MPH before it cuts back.
Then it goes back to the first cycle again to not quite 20MPH, or maybe to the second cycle where it's around 20.4MPH.
That set of cycles will repeat constantly as long as I hold any throttle position, under any road conditions or wind (the actual speeds may vary, but the cycle itself does not).
If I immediately re-ride the same stretch of road in the opposite direction, it doesn't repeat the variations in reverse, but they instead happen in the same "random" manner they did the first time, implying they have nothing to do with the terrain. Same is true of re-riding it in the same direction.
The problem also occurs to a lesser degree (lower variation, mostly, and far lesser "kick" from the acceleration) when using hte 12FET to control the front 9C 2806 26" wheel. But it still happens in the same way.
What I'm looking for are potential ways I can deal with this issue.
Most likely, I will have to reprogram the controller, assuming it is simply a parameter in it that is not correctly set up.
Presently I do not have any way to try reprogramming the controller (my USB link from Lyen is somewhere in one of the sheds at the house (assuming it's not stolen with other stuff by looters), inaccessible until the house is repaired and I can move back in, probably at least a month and a half or two months from now).
If it is not a programmable function, then I may also be able to physically alter the controller, but I would guess that if it's not a setting change that it is something in the way this firmware works. If that's the case, I would love to find someone willing to trade an either older or newer Grin Tech 12FET for this one, as long as that one is working normally, doens't need repair, is reliable and doesnt' have this problem--meaning it will actually *hold* a particular speed when commanded to a particular throttle voltage, assuming flat terrain and either no wind or constant wind. (basically, under a constant load).
It's from this post:
http://www.endless-sphere.com/forums/viewtopic.php?p=747654#p747654
I mentioned this problem (at some length) in my CrazyBike2 build/evolution thread, here:
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=779515
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=781325
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=820114
Other mentions are here:
http://www.endless-sphere.com/forums/viewtopic.php?p=747862#p747862
At one point I mistakenly thought the CA was causing the problems:
http://www.endless-sphere.com/forums/viewtopic.php?p=748492#p748492
but I was very wrong. I don't know why I didn't have problems at that time, but did before and later.
http://www.endless-sphere.com/forums/viewtopic.php?p=748896#p748896
The basic issue is that regardless of method used to set a constant throttle voltage input directly to the 12FET's throttle connection, and regardless of which motor is being controlled by the 12FET, speed does not remain remotely constant even on level ground with no wind. Speed decreases by at least 1MPH, then increases by at least 1-2MPH, and cycles intermittently (not on a specific time or frequency), over several seconds to nearly a minute (varies).
It *will not* simply let me ride at a constant or even near-constant speed, unlike any other controller I've ever used.
AFAICT using a meter, no voltage variation from the throttle itself occurs while it's set at any particular point, so it's not being commanded from the throttle itself--it's something in how the controller works.
The throttle is run direct, not thru a Cycle Analyst. The only CA connection to the controller I had (which I don't now) was for the speedo sense wire and ground.
I can see the power dropping dramatically, but not completely (despite what I posted in the above links), when the controller rolls back output. If I am at say 500W battery draw, it'll drop to 200W suddenly, until the speed drops far enough, and hten it will surge back to well above 500W (maybe 800-900W, depending on conditions at the time) till it reaches it's overspeed, then it will roll back, and cycle like that.
It doesn't go to the same speed, either under or over, each time, but rather oscillates around and each peak may get higher and higher successively, until at some point it reverses the trend. Same for rollback--it may drop to lower and lower speeds, until at some point it reverse the trend. But the trend is just a trend--it will sometimes still peak lower somehwere during a rising trend, etc.
Fixes tried so far, with identical results for each, were:
--Zombiess Throttle Tamer, to try to smooth out possible throttle voltage variations (even though I dind't see any variations, it dind't mean they weren't there, perhaps).
--Gripping the bar and the thumb throttle so tightly it hurt, to guarantee that my fingers weren't moving the throttle and causing it to happen.
--Tightening the grip against the throttle body hard enough for friction to hold the throttle in one physical position unless I drag it back to wehre it was (defeating it's internal spring, effectively).
--Uisng a switch to flip over from thumb throttle's signal line to a resistive divider instead, to input a specific voltage to hold a speed.
--Using a potentiometer as voltage-divided throttle.
--Using a different throttle, on hte left bar, wiht my left hand instead of right.
More specific behavior, to edit (for clarity and updated info) and summarize from the first linked post:
When using this 12FET to control the HSR3548 in 20" wheel on the rear, I put throttle at WOT from a stop, and it accelerates as desired (with or without using *both* front and rear for the first few seconds to get going quicker, with front 9C/6FET on a separate throttle), all the way up to my normal riding "top speed", which is just shy of 20MPH, exactly as I want. (top speed of the system is probably a lot higher than that, but I don't use it under any normal conditions).
Then it creeps up to say, 20.4MPH, which I could live with--I don't think the police would care about half a MPH; my speedo in the CA probably isn't even accurate to that since it's just set for basic diameter of a 20" tire. But as soon as it reaches that, maybe a second or two later, power cuts way way down, perhaps in half.
Then it goes back up just a little in power but not enough to hold the speed, and coasts down to as low as 18.5MPH.
Then it applies another long burst of power, this time going up to as high as 20.9MPH.
Then power cuts again, and eventually cycles back on and goes even higher the third time, up to 21.5MPH before it cuts back.
Then it goes back to the first cycle again to not quite 20MPH, or maybe to the second cycle where it's around 20.4MPH.
That set of cycles will repeat constantly as long as I hold any throttle position, under any road conditions or wind (the actual speeds may vary, but the cycle itself does not).
If I immediately re-ride the same stretch of road in the opposite direction, it doesn't repeat the variations in reverse, but they instead happen in the same "random" manner they did the first time, implying they have nothing to do with the terrain. Same is true of re-riding it in the same direction.
The problem also occurs to a lesser degree (lower variation, mostly, and far lesser "kick" from the acceleration) when using hte 12FET to control the front 9C 2806 26" wheel. But it still happens in the same way.
What I'm looking for are potential ways I can deal with this issue.
Most likely, I will have to reprogram the controller, assuming it is simply a parameter in it that is not correctly set up.
Presently I do not have any way to try reprogramming the controller (my USB link from Lyen is somewhere in one of the sheds at the house (assuming it's not stolen with other stuff by looters), inaccessible until the house is repaired and I can move back in, probably at least a month and a half or two months from now).
If it is not a programmable function, then I may also be able to physically alter the controller, but I would guess that if it's not a setting change that it is something in the way this firmware works. If that's the case, I would love to find someone willing to trade an either older or newer Grin Tech 12FET for this one, as long as that one is working normally, doens't need repair, is reliable and doesnt' have this problem--meaning it will actually *hold* a particular speed when commanded to a particular throttle voltage, assuming flat terrain and either no wind or constant wind. (basically, under a constant load).