Brushed Controller...how to make throttle input less sensetive

[unclejemima]

I've got a brushed controller on an older ebike that I'm working on. It works great except the throttle is VERY sensitive and its nearly impossible to drive it without it jerking around like a jerk

Is there some kind of resistor or something I can put inline to the motors (or even to the 5v throttle) that would delay or somehow smooth out the throttle input???

Thanks!

 

[fechter]

If you put a resistor in series with the throttle signal, it will be less sensitive but you won't get full speed. I found that when using a hall effect throttle, if there is too much travel before the motor starts, it becomes very sensitive at the low end. Placing a trimmer pot in series with the throttle ground line, you can dial it in so there isn't as much travel before the motor starts. This greatly helps with the sensitivity. I used a 200 ohm, 10-turn.

Some controllers have a ramp-up adjustment pot inside or in software.

What kind of controller is it?

 

[amberwolf]

Which kind of throttle are you using? If it's a hall throttle, you might change to a potentiometer type instead, or better yet use a cable-operated throttle and then a regular throttle grip or thumb type from an ATV/etc.

A COT can be either a pot or hall type; if it's a pot you can even change out the pot to a different type in some cases, so a linear pot could be changed to a logarithmic one, etc.

Or use a pulley to do the same job the Travel Agent from Problem Solvers would do, on the COT's cable.

If it's a hall type controller and you use a pot, you'll need to use some resistors on the ground and 5v supply to it to make it act within the correct range for the controller.

If it's a pot type controller and you use a hall, it may be "already on" even when throttle is off, and behave improperly in various ways as you increase throttle, and also won't reach the full power / speed of the controller/motor/system because the hall doens't go up high enough in voltage.

 

[unclejemima]

If you put a resistor in series with the throttle signal, it will be less sensitive but you won't get full speed

How much would it pull down my max power? If the throttle is 0-5V, does the resistor then only allow 4.8V kind of thing?

Any amazon or ebay link you could provide for something I could use?

 

[fechter]

How much would it pull down my max power? If the throttle is 0-5V, does the resistor then only allow 4.8V kind of thing?

Yes, it would be more or less a linear function of the signal voltage. There are several ways to implement this. The simplest would be to place a trimmer pot in series with the signal wire. The value of the pot would depend on the controller. If you use an ohmmeter to measure from the signal wire to the ground wire coming from the controller with the throttle disconnected, you should see something like 10k-20k ohms. If the pot value equals the controller input resistance, you could vary the maximum power from 50% to 100%.

Some controllers have a safety feature that will stop output if the throttle signal gets outside of an allowable range. You could possibly run into this by placing the resistor in series with the signal line.

Another approach is to put a resistor in series with the 5v line going to the throttle. In this approach, I would guess around 500 ohms. This keeps the zero throttle voltage about the same but limits the top end.

You can search Amazon or any electronic supply for "10-turn trimmer pot". Using a pot makes things adjustable.

What kind of controller do you have?

 

[amberwolf]

If you install the pot so one of the end wires connects to the throttle's signal output wire, the other end wire to the throttle ground wire, and the pot's center wire to the controller throttle signal input wire, you can vary the scale of the throttle signal from zero to 100% (as long as the resistance of the pot doesn't interfere with the controller's throttle input stage design; if it's meant for hall throttle types then it should work fine, if it's meant for pot throttles sometimes this doesn't work very well at low pot values, and sometimes it triggers the safety feature Fechter mentions above. )