smoothing out the throttle

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nonlineartom   1 kW

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smoothing out the throttle

Post by nonlineartom » Nov 19 2011 2:34pm

My new build is a 10T MAC motor with a 12fet 50 amp controller running at 44V, the problem is, the takeoff from a standing start is a bit brutal. The MAC is renowned for it's ability to chow down on amps but it's really quite annoying that unless you really gently rotate the throttle it will lurch forward trying to throw you off the back, I've got a 30A limit set on the CA but that only kicks in quater of a second after takeoff to choke the power which can cause even more jerkyness. The controller is currently factory standard but I plan to use the USB cable to set a 30A limit on the controller itself rather than using the CA to limit the power.

So my question is this? is there anyway to ramp the throttle up over time? or otherwise smooth out the throttle response so if I give it 80% throttle in an instant, it actually goes from 0% throttle to 80% throttle over 1-2 seconds to stop the "bite" and behave a bit more like a clutch on a car easing in the power. I don't really want to set a lower limit on the controller itself as I need all those amps for climbing the big hills, the 3 speed switch helps a little bit as it stops the launch being so ferocious but it's a speed limit not an amp limit. Anyone have any experience in this?
Commuter bike: 10T MAC Schwinn Panther Beach Cruiser on 12S LiPo, super stealth hill eater
Forest trail eater: Crystalyte 5306 KMX Viper with 24" wheel. 100A controller 18S LiPo
Pocket rocket: 8T MAC e-BMX 18s LiPo. Missile for testing to destruction
Summer ride: 8T MAC Kona Joe MTB / chopper / beach cruiser hybrid bike. 24" wheels and a lot lot of style.
--------------------------------------------------------------------------------
Respect and fear the ancient god LiPo and pray he is merciful.

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shock   1 kW

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Re: smoothing out the throttle

Post by shock » Nov 19 2011 4:36pm

Maybe modify your throttle, or try a different throttle?
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dumbass   100 kW

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Re: smoothing out the throttle

Post by dumbass » Nov 19 2011 7:32pm

I think the answer is as much or more in the controller as in the throttle.

Bob

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briogio   100 W

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Re: smoothing out the throttle

Post by briogio » Nov 19 2011 7:59pm

nonlineartom wrote:My new build is a 10T MAC motor with a 12fet 50 amp controller running at 44V, the problem is, the takeoff from a standing start is a bit brutal. The MAC is renowned for it's ability to chow down on amps but it's really quite annoying that unless you really gently rotate the throttle it will lurch forward trying to throw you off the back, I've got a 30A limit set on the CA but that only kicks in quater of a second after takeoff to choke the power which can cause even more jerkyness. The controller is currently factory standard but I plan to use the USB cable to set a 30A limit on the controller itself rather than using the CA to limit the power.

So my question is this? is there anyway to ramp the throttle up over time? or otherwise smooth out the throttle response so if I give it 80% throttle in an instant, it actually goes from 0% throttle to 80% throttle over 1-2 seconds to stop the "bite" and behave a bit more like a clutch on a car easing in the power. I don't really want to set a lower limit on the controller itself as I need all those amps for climbing the big hills, the 3 speed switch helps a little bit as it stops the launch being so ferocious but it's a speed limit not an amp limit. Anyone have any experience in this?
I found the same thing with my front wheel drive mountain bike, going up steep hills the throttle was too abrupt and the front wheel would just spin out and I'ld have to get off. First I changed from a thumb to a twist, but both of them were 1/4 turn (most of them are) and I think that's the problem, so after a lot of looking around I've sourced a full turn, twist throttle, hopefully that will make it easier to modulate. It's on its way and I'll let you know how it works out.

John in CR   100 GW

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Re: smoothing out the throttle

Post by John in CR » Nov 19 2011 8:11pm

Briogio,

When you get it and it does turn out to be a long twist, please give us a link. This is a common problem especially on high power rigs.

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Icewrench   10 kW

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Re: smoothing out the throttle

Post by Icewrench » Nov 19 2011 8:18pm

You might try setting Block Time in the controller to near zero.
I think block time allows full amps at take off,
the higher the block time number the longer amps are not regulated.

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nonlineartom   1 kW

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Re: smoothing out the throttle

Post by nonlineartom » Nov 19 2011 8:27pm

isn't that the opposite of what I want? i want limited amps on takeoff and then to steadily allow more amps as I continue, for allowing prolonged hill climbing, but preventing heavy current draw on takeoff. This could be done with some kind of throttle regulator of some sort, or is there something at controller level which will just prevent sudden current spikes?
Commuter bike: 10T MAC Schwinn Panther Beach Cruiser on 12S LiPo, super stealth hill eater
Forest trail eater: Crystalyte 5306 KMX Viper with 24" wheel. 100A controller 18S LiPo
Pocket rocket: 8T MAC e-BMX 18s LiPo. Missile for testing to destruction
Summer ride: 8T MAC Kona Joe MTB / chopper / beach cruiser hybrid bike. 24" wheels and a lot lot of style.
--------------------------------------------------------------------------------
Respect and fear the ancient god LiPo and pray he is merciful.

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Icewrench   10 kW

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Re: smoothing out the throttle

Post by Icewrench » Nov 19 2011 8:34pm

Block time at 3 will give 3 seconds of full on max power.
Block time at .5 will give max power for 1/2 second.


http://endless-sphere.com/forums/viewto ... ng#p455705

and another one

http://www.endless-sphere.com/forums/vi ... 16&t=14836

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neptronix   100 GW

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Re: smoothing out the throttle

Post by neptronix » Nov 19 2011 8:48pm

Typical of all MAC/BMC builds.

Block time has nothing to do with it. Been there done that. No change.
50 amps is too much for a 10T. It's overkill on an 8T even at 36v.

Has to do with the current sensing & other various things on infineon controllers.
On anything other than a recent cell_man controller or an old crystalyte analog, this effect will be quite bad.

( this has been discussed heavily in the forums and i tried EVERYTHING myself.. the cure was a lower amp setting and the new cell_man controller. )

Sorry dude but you have to kick your amps down by programming the controller. That's all you can do here.
Efficiency is everything :bolt:

My first major build: 1.6kW 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w @ 4kW on a Turner O2 full suspension.
The monster scooter: 20" eZee on a Cannondale Semi Recumbent.
Whipper-snapper: ? on a lightweight BikeE Semi Recumbent

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Sacman   10 kW

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Re: smoothing out the throttle

Post by Sacman » Nov 19 2011 10:15pm

Have you tried using a throttle that varies logarithmically rather than linearly?

el_walto   10 kW

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Re: smoothing out the throttle

Post by el_walto » Nov 20 2011 12:37am

You could try wiring your throttle through your cycle analyst, using it as a current throttle. Not sure if this would help or not.

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dogman dan   100 GW

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Re: smoothing out the throttle

Post by dogman dan » Nov 20 2011 8:38am

Not having that effect is one of the reasons I fell in love with the extreme low speed windings of 9c motors.

I get really smooth throttle response, at the expense of needing to run 72v to have any top speed at all. With my 2812, I get a lot of finesse at low speed, or starting up. And climb hills difficult to walk up without falling on your ass. 25 mph is plenty fast in the dirt, knowing I'll go over the bars from time to time.

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gwhy!   1 MW

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Re: smoothing out the throttle

Post by gwhy! » Nov 20 2011 10:45am

I have made a throttle interface for one of my bikes that has a few functions, one of those functions is the ability to program your own throttle curve into, It works quite well for smoothing out the initial roll on of the throttle. A much simpler interface could be put together from a picaxe 08M with 3 or 4 resistors and a cap, the power for the chip will uses the throttle 5V line so it is minimal wiring ( 3 wires in and 3 wires out (inline with the throttle wires)). If anyone is interested i will draw up a circuit and post a basic program for people that would like to have a play.

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fechter   100 GW

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Re: smoothing out the throttle

Post by fechter » Nov 20 2011 1:18pm

You could also probably make an analog circuit that slows the throttle ramp up. Trick here is you want to slow the ramp up but not the ramp down so the motor stops right away when you let off the throttle.
"One test is worth a thousand opinions"

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gwhy!   1 MW

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Re: smoothing out the throttle

Post by gwhy! » Nov 20 2011 3:28pm

fechter wrote:You could also probably make an analog circuit that slows the throttle ramp up. Trick here is you want to slow the ramp up but not the ramp down so the motor stops right away when you let off the throttle.
I tried it this way but it introduces a slight delay when rolling the throttle on, so wasnt really any good for my purpose.

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gwhy!   1 MW

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Re: smoothing out the throttle

Post by gwhy! » Nov 20 2011 4:06pm

here is a basic diagram to use a picaxe08M for a throttle interface.
picaxe08 TI.jpg
picaxe08 TI.jpg (15.44 KiB) Viewed 3309 times
it could be made to be hard wired into the throttle lead and cover it with some heatshrink.

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briogio   100 W

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Re: smoothing out the throttle

Post by briogio » Nov 20 2011 4:11pm

gwhy! wrote:I have made a throttle interface for one of my bikes that has a few functions, one of those functions is the ability to program your own throttle curve into, It works quite well for smoothing out the initial roll on of the throttle. A much simpler interface could be put together from a picaxe 08M with 3 or 4 resistors and a cap, the power for the chip will uses the throttle 5V line so it is minimal wiring ( 3 wires in and 3 wires out (inline with the throttle wires)). If anyone is interested i will draw up a circuit and post a basic program for people that would like to have a play.
Holy crap this sounds complicated :shock: I thought I could just get a throttle with more twist to throttle ratio and be good to go! :roll: Guess I'll find out when my full turn twist throttle comes whether it works or not, least I didn't pay too much for it :wink:

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Re: smoothing out the throttle

Post by gwhy! » Nov 20 2011 4:21pm

briogio wrote:
gwhy! wrote:I have made a throttle interface for one of my bikes that has a few functions, one of those functions is the ability to program your own throttle curve into, It works quite well for smoothing out the initial roll on of the throttle. A much simpler interface could be put together from a picaxe 08M with 3 or 4 resistors and a cap, the power for the chip will uses the throttle 5V line so it is minimal wiring ( 3 wires in and 3 wires out (inline with the throttle wires)). If anyone is interested i will draw up a circuit and post a basic program for people that would like to have a play.
Holy crap this sounds complicated :shock: I thought I could just get a throttle with more twist to throttle ratio and be good to go! :roll: Guess I'll find out when my full turn twist throttle comes whether it works or not, least I didn't pay too much for it :wink:
A throttle with more travel will/do help loads and it may be fine for you. the component cost for the above circuit will only be about £2 but if your not already into programming picaxe chips then you will also need a picaxe download lead which is around £5

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briogio   100 W

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Re: smoothing out the throttle

Post by briogio » Nov 20 2011 5:34pm

gwhy! wrote:
briogio wrote:
gwhy! wrote:I have made a throttle interface for one of my bikes that has a few functions, one of those functions is the ability to program your own throttle curve into, It works quite well for smoothing out the initial roll on of the throttle. A much simpler interface could be put together from a picaxe 08M with 3 or 4 resistors and a cap, the power for the chip will uses the throttle 5V line so it is minimal wiring ( 3 wires in and 3 wires out (inline with the throttle wires)). If anyone is interested i will draw up a circuit and post a basic program for people that would like to have a play.
Holy crap this sounds complicated :shock: I thought I could just get a throttle with more twist to throttle ratio and be good to go! :roll: Guess I'll find out when my full turn twist throttle comes whether it works or not, least I didn't pay too much for it :wink:
A throttle with more travel will/do help loads and it may be fine for you. the component cost for the above circuit will only be about £2 but if your not already into programming picaxe chips then you will also need a picaxe download lead which is around £5
Phew that's good to hear! :wink: also good to know that you have the complicated solution to try if it doesn't work out satisfactorily 8)

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nonlineartom   1 kW

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Re: smoothing out the throttle

Post by nonlineartom » Nov 20 2011 5:57pm

Lyen PM'd me and claims to sell a magical device which fixes all my woes. Sits between the throttle and the controller, he claims it's an analogue circuit that slows the ramp up of the throttle so it takes a second or two to reach full throttle no matter how quick you slam the throttle, seems perfect to me, too good to be true?
Commuter bike: 10T MAC Schwinn Panther Beach Cruiser on 12S LiPo, super stealth hill eater
Forest trail eater: Crystalyte 5306 KMX Viper with 24" wheel. 100A controller 18S LiPo
Pocket rocket: 8T MAC e-BMX 18s LiPo. Missile for testing to destruction
Summer ride: 8T MAC Kona Joe MTB / chopper / beach cruiser hybrid bike. 24" wheels and a lot lot of style.
--------------------------------------------------------------------------------
Respect and fear the ancient god LiPo and pray he is merciful.

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briogio   100 W

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Re: smoothing out the throttle

Post by briogio » Nov 20 2011 6:30pm

nonlineartom wrote:Lyen PM'd me and claims to sell a magical device which fixes all my woes. Sits between the throttle and the controller, he claims it's an analogue circuit that slows the ramp up of the throttle so it takes a second or two to reach full throttle no matter how quick you slam the throttle, seems perfect to me, too good to be true?
Sounds good, how much?

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nonlineartom   1 kW

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Re: smoothing out the throttle

Post by nonlineartom » Nov 20 2011 6:53pm

The module intercept the throttle and delay the signal from the throttle to the controller. It can be install internal inside the controller, or external inline between the controller and the throttle. The "gentleness" is adjustable only if you do not mind swap out an electronic component yourself, but it can be bypass with the optional bypass jumper (+ $2).

$20 plus shipping. I've ordered one and I'll add it to my build thread and report back
Commuter bike: 10T MAC Schwinn Panther Beach Cruiser on 12S LiPo, super stealth hill eater
Forest trail eater: Crystalyte 5306 KMX Viper with 24" wheel. 100A controller 18S LiPo
Pocket rocket: 8T MAC e-BMX 18s LiPo. Missile for testing to destruction
Summer ride: 8T MAC Kona Joe MTB / chopper / beach cruiser hybrid bike. 24" wheels and a lot lot of style.
--------------------------------------------------------------------------------
Respect and fear the ancient god LiPo and pray he is merciful.

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gwhy!   1 MW

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Re: smoothing out the throttle

Post by gwhy! » Nov 20 2011 7:23pm

nonlineartom wrote:The module intercept the throttle and delay the signal from the throttle to the controller. It can be install internal inside the controller, or external inline between the controller and the throttle. The "gentleness" is adjustable only if you do not mind swap out an electronic component yourself, but it can be bypass with the optional bypass jumper (+ $2).

$20 plus shipping. I've ordered one and I'll add it to my build thread and report back

as long as the throttle can be returned to zero without any delay, you may be happy with it. I needed the low speed control but without the delay.

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Re: smoothing out the throttle

Post by d8veh » Nov 21 2011 7:54pm

gwhy! wrote:here is a basic diagram to use a picaxe08M for a throttle interface.
picaxe08 TI.jpg
it could be made to be hard wired into the throttle lead and cover it with some heatshrink.
IIUC you're pulsing the output (PWM) and then using a low pass filter to make an analogue signal for the controller. I thought the new M series Picaxe microprocessors could give direct analogue outputs. Have I got this right?

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GMUseless   100 W

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Re: smoothing out the throttle

Post by GMUseless » Nov 21 2011 8:29pm

The analog solution is pretty simple, it's like 4 or 5 components...use a dual op amp like a TL072 as a voltage follower with a pot in between and a capacitor to ground. It's a standard slew or lag circuit. You can also add a diode to bypass the pot to give a single sided ramp (i.e. ramp up...but instantly drop off....like what you'de want in a throttle.) When I get back to my work computer, I can draw up a schematic is anyone is interested.

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