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**Tommycat** · 07-31-2018, 01:19 PM

Throttle Testing...

One must start out with the hazards involved. I recommend working on your throttle under test bench conditions using a battery powered voltage (5+vdc) supply.Where you'll be comfortable, have better accuracy, and don't have to worry about the motor or wheel starting up. If not possible, or when you have to see the controller input/output. Be very wary of motor start-up and operation. Keeping the bike position steady and the wheel securely held off the ground.

Then look for the obvious! Something blocking or in the way of full thumb throttle rotation operation? Bracket or display mount perhaps. Unusual noises, sticking, or grinding when twisting? If so skip the voltage testing for now, and open it up and correct the rotation problem first.

The electrical hazard at the hall sensor itself could be considered low, as you'll be working with 5vdc at about 6mA. But of course be aware of any higher voltages close by. On my Pie, full battery power is in the same harness connector and in the throttle housing. Be careful not to get these inadvertently switched or shorted! When in doubt as to what goes where... open them up and take a look! See disassembly instructions farther below...

From here on out for wiring reference only, the 5 vdc + input wire will be RED. The 0vdc ground wire will be BLACK. And the sense wire will be GREEN.

You must determine and verify which wire color goes to which!

Input positive voltage may also be referred to as 5 vdc even tho it typically varies between 4.25 and 5 vdc or so.

As any electronic component could be, the hall sensor can be damaged. Mechanically as in broken terminal legs or excessive hard vibration. And electrically by over voltage input, over current (shorts), or reversed polarity... all to be avoided!

With the low current of the throttle circuitry. Erratic operation from the throttle wiring getting WET is a known issue. They are not water proof unless specified and if full battery voltage is in same housing, may get shorted.

Throttle Wiring...

The hall sensor throttle requires three wires to operate. Red for 5+vdc, Black for 0 vdc-battery ground, and Green for sensor output.

The most important thing to get right is knowing which wire are which. Wiring colors used vary between manufactures and can not be trusted!
So always verify!

If your fortunate to have a wiring or connector pin-out diagram, use it! On the examples below or any other diagram, be sure and notice which side of the connector you are on. Male (with the PINS) , or female. As the opposite side pin-outs will be mirrored. Very easy to mix up, be careful here. Then check to be sure.

Bafang Mid Motor Harness Connection Pin-Out.

5 WIRE Throttle with Key Switch and Voltage Display.

6 Wire with Key Switch and Voltage Display.

If unknown, you can start at the hall sensor itself, see the input and output terminals on the diagram below. And confirm visually which wire colors are connect to each leg. They should be well soldered and properly insulated to prevent shorting. The beveled side of the sensor, with the part number stamped on it will face towards the magnet.

If you need to disassemble your throttle for wire colors and/or further troubleshooting... see throttle disassembly below.

Controller Wiring...

Note: the controller 5 vdc regulator is not very powerful and is only rated to provide around 100mA or even less.(I've seen down to 40 mA) Do not short out the supply wires. It will survive a brief short, which I unfortunately can attest too. But probably not for an extended period, which I decline to verify...

Insure correct battery power voltage to controller. Some controllers require an activation (key switch or button...) or "on" signal to it before energizing 5+vdc supply.

Have a map?...Good use it

If not start by checking the three wires for the 5+vdc regulated output power with a good quality multi-meter.

Mark the positive wire as 5 vdc +(Typically RED and reference color in this thread), Then using a DMM with high resolution and keeping the positive probe there...check the other two wires with the Black test lead, both will provide a grounding path, but the sensor wire has a little resistance in it. So true o vdc battery negative wire or ground will have the highest voltage potential. Mark it 0vdc or ground. (Typically Black and the reference color in this thread.) With the throttle sensor signal input wire, just a hair less voltage potential. Mark it signal input. (Typically Green or White, Green as the reference color in this thread.). Example: In my testing, from 5+vdc to true ground meter read 5.07 vdc. And to signal input wire, read 5.06 vdc.

To double check ground. Disconnect battery and allow capacitors to discharge. Then check resistance between negative battery connector connection and previously identified throttle ground, there should be NO resistance what so ever as it is a direct connection.

If you open up the controller and are able to see the PCB labels. Positive power wire for the throttle (5+vdc)will go to the terminal labeled SP5V. Negative or Ground wire (0vdc) will go to GND, and Sensor wire will go to SP.

If your controller has more than 3 wires going to the throttle, odds are one of them has full battery + power going to an LED or some type of voltage display, or perhaps a power/key switch. Keep this full battery voltage away from the wiring used by the Hall Sensor in the Throttle! Although the ground or Black wire may be shared by the hall sensor and voltage display.

Once you have all the wires sorted, we can get to testing. The first thing you ought to know by now is if your controller is providing 5 vdc regulated power.( On the Pie, more around 4.3 vdc).
If not, it's a problem relating to the controller. Check to see if the controller is activated and powered on and/or if any of the 5+vdc supply wires to other 5vdc components (such as PAS, brake cut-out, gear sensor, or speed sensor) are being accidently shorted.
Having 5+ vdc available, continue on to the throttle checks.

Having an external and open connector such as a JST, will make things easy, as you can just back-probe the connections. See this great guide for general testing.

Good Throttle Testing Guide...

Pie owners have it a bit more difficult with the weather proof HIGO connectors. I made up a set of jumper wires that have a female connector on one end, and a male pin on the other, with an extra pig tail. To make electrical connections and access for testing voltages with the throttle fully functional.

Throttle Output and Profiling...

After correct input voltage and proper ground is verified, sensor output voltages are now taken. At throttle off or minimum position, output voltage should read about .84 vdc. At WOT (wide open throttle) full on, voltage should read around 4.25 vdc. Don't get to hung up on exact readings as they very a bit. If magnet is missing or removed, output should be about 2.5 vdc.

***If you have a certain specific issue that you would like to identify and resolve, a throttle output profile is a great way to visually see the problem. Throttle dead zones, erratic operation, and wheelie starts to name a few can be plotted and looked at for fixes.***

First tape off and mark your throttle's twisting motion into 10 equal segments, 0% to 100% (AKA, WOT for wide open throttle) operation in 10% increments.

Then use this form to fill out the voltage output readings at each graduated step.

A typical well working throttle output plot will look like this...

You should have a nice straight line between the starting and ending "hooks".
Voltage required for maximum desired motor speed, and amperage draw may also come in handy. From this it can be more easily determined what the problem is with your throttle, and possible solutions to make it better. See Modifications in the next chapter.

O.K. so now you see that a problem exists and need to get access to the internal components, such as the magnet, hall sensor, wiring and connections of your throttle to check out.

Throttle disassembly...

Thumb throttle is easy to see and describe. First push in on the three retaining tabs that hold the assembly together, a type of three finger salute will do. Being careful of the return spring which is under tension. Mark spring position and securing points as required to get it back properly in place during reassembly.

Remove housing retaining screw, and all should be accessible now.

Full twist throttle is a bit more difficult to get apart as you need to reach up thru the middle of the housing (throttle off the handlebars) to unlock the same type locking tabs.

I found that a tool kit like this is a must. Try bending one or two tabs inward, while applying prying separating force to housing. For more information on this look
HERE!

After access is gained, check to see that the magnet is clean and secure in it's proper position. And that the hall sensor is in it's proper position ( 1-2 mm from magnet face, beveled side with part stamp facing magnet) and sitting snug and secured, bottomed out in it's holder. Verify that it's wiring is sound, properly connected and insulated from shorting.

Bottom line...

5+ vdc in with good ground... with .8 to 3.4 vdc linear out depending on throttle position.

**Tommycat** · 07-31-2018, 01:25 PM

Hall Sensor Throttle Modifications...

Please note that a lot of controllers have the capabilities thru programming to modify operational parameters that can achieve results as obtained below, some even better. Checking your controller documentation first is highly recommended.

Introduction: By now you should have a good understanding of how the hall sensor throttle works, it's power in and power out. If you don't read the sections above.
In this section I'll discuss ways to manipulate the output, ether electrically or mechanically if you have the capabilities and desire to do so... Thereby changing it's operating characteristics.

I have both bench tested first, then field tested the below modifications with both a Luna full twist throttle. And a generic thumb throttle, both of which use SS49E hall sensors. So I am confident that they actually work.

That said, not all controllers or throttles are the same so please take precautions as you see fit before experimenting. Brake cutouts should always be used.As an added precaution I ran the 5 vdc throttle supply thru my throttle latch/on switch (which is usually used as a light switch) to use as a manual kill switch. Handy to disable the throttle output while working on the bikes electrics preventing unwanted accidental motor start up from bumping the throttle... And always check operation first in the shop with the wheel up, to make sure everything is perfect.

As a hall sensor is relatively inexpensive I believe the first goal is to protect the 5 vdc power supply coming from the controller. Which is not easily replaced, and the cost for a new controller unappealing.

For this reason while testing I use 3 multimeters... One meter in series with the positive power 5 vdc supply to observe amperage draw. (Keep below 10mA.) One meter reading supplied voltage, and one meter reading output voltage. A truly cautious modder may want to install an inline fuse of about 20mA, if there is such a thing. I never saw an amp draw over 10mA, even with multiple transistors. Typically for the modifications below, amp draw will actually be reduced. Of course all bets are off if you accidently short the incoming voltage which I did once. Luckily my meter put up an alarming racket which prevented any damage. Proceed at your own risk...

Remember... No excessive voltage, amperage, or reversed polarity. And with the low circuit ampacity, high quality soldered connections are a must.

Bench testing in action... I like to use a 5 vdc rechargeable battery supply.

Field testing in action...

#1 Starting Voltage/ Dead Zone Elimination Mod...

Will help if you have to turn your throttle too much before your motor starts (front end dead band). Or to much of a jerk at start. Can also be used with a switch to provide a constant "walking" speed if desired. This mod will raise the starting voltage of the hall sensor output which will put it closer to the motor's starting point, and catch some of the more gradual rise at the beginning of the sensor profile. Note: this mod will not change the final (WOT) voltage output. More important is that the loss of sensor ground will result in full voltage output. AKA- FULL MOTOR OUTPUT. See precautions above! Leave enough room between starting voltage and motor start for an accidental slight bump of the throttle. Although the hall sensors themselves have a bit of temperature sensitivity, this is countered by the IC chip's build and negated to the point of not being a real concern.

Modification results profiled.

#2 Ending Voltage/ Maximum Speed Mod...

Will provide you with a means to regulate top end speed. Good for the grand kids bikes or to keep under mandated speed regulations...

OR

November 24th, 2019: Using my controller in actual operation trying both options I can see no electrical downside to ether wiring usage. I have used the top diagram (with use of ground) with no problems at all and had stopped there. But recently I was questioned as to if the ground was actually needed. So doing more tests I determined that the ground connection was not necessary as far as my controller's operation was concerned. This would seem to be more desirable, as it requires fewer wiring modifications. So I added it here. The choice is yours.

Data that I took to make this decision...

#3 Double Dipper Mod...

Just a combination of the first two... easier to understand?

#4 Delay Voltage/ Smooth Acceleration Mod...

If after trying the #1 mod which has been known to smooth out an abrupt start, this one may work for you with a few more components...
Also known as the anti-wheelie fix. :-) This mod is used to smooth out the acceleration curve by providing a delayed, gradual, and consistent timed on voltage output. With the usual off voltage drop or deceleration. Using the starting voltage mod with the extra electronic components works well. This mod requires more "tuning" of the pots due to the differences in your controller's internal resistances. Increasing the capacitor value will increase the time delay, but may also increase motor off time. This mod may decrease top speed a bit.

Your goal with TP1 is to increase the fill-up time of the capacitor, more resistance longer delay. But not reduce final output voltage.
Your goal with TP2 is to keep the starting voltage in desired range. More resistance, higher starting voltage.

#5 Mechanical Mod...

Electronics not your thing? There are still possibilities in the mechanical realm. But it will probably take more patience and testing to get just the right results.
Manipulation of the magnets gauss to sensor will be tricky to say the least. More trial and error is to be expected...
Easiest, and probably most reliable that would start you out, is to change the position of sensor to magnet. Raising the sensor up in it's slot at least 1mm if space is available or increasing the gap between sensor and magnet would result in the change as shown in the graph below...

The loss of over all gauss will increase the starting voltage and decrease the ending voltage With the midpoint remaining the same. Be wary of not getting the starting voltage too high or too close to the motors starting point. And don't reduce the top end below the point of getting full power from your controller.

Other experiments can be tried using Mu-metal to block magnetic field, or steel to modify it. A two magnet throttle would offer the most opportunity for manipulation. But I've never had reliable or acceptable results trying this...

Another physical mod would be to adjust the stops on the throttle movement. Which would also eliminate dead-band, but also reduce the total amount of twist rotation. Which in some instances may be preferred.

Good example of this HERE.

An impressive first finger to thumb throttle modification can be seen HERE.

**Tommycat** · 08-12-2018, 05:31 AM

Verifying Controller Operation...

O.K. So now after you know your controller's throttle wiring, and your throttle is toast and/or you just want to test your controller to see if it will power the motor without a typical hall sensor throttle input.

After properly securing bike/wheel for testing... here are three possibilities, ranked in order of my preferred preference. Just looking for an easy mid level or lower, motor speed actuation.

Pie owners be wary of full battery + power in throttle harness! Re-check those pin-outs! See wiring diagram above. 5+vdc pin #1, Sensor pin #2, Ground pin #3. Keep separation with insulation. Do not short.

Note: During testing on start-up the controller will set a loss of throttle error (#2) as you must always start with no input (no throttle input safety). Then apply sensor voltage input for a couple seconds, then remove for a second, then reapply.
Well O.K., you could wire everything up. Turn on the power, then remove sensor input for a second, and then reapply. Be prepared to start/stop the input sensor voltage.

Throttle (test inputs) on the left, controller connections are on the right.

#1 Use a 3 vdc battery to produce the sensor voltage input. Pros... No danger of accidently shorting 5+vdc power as it's not used. Puts out a nice mid level speed voltage. Can use just a small, compact, "button" type battery. Safe, simple, direct, and smooth.

#2 One 15 K ohm resistor is series with the 5+vdc supply. Pros... Single part and easy wiring (if any) required. Good mid level speed voltage.

#3 Two resistors in a voltage splitting configuration. Pros... Good mid level speed voltage. Very accurate, reliable, and steady. Closest to typical current draw.

Had read that a diode could be used in series with the 5+vdc power... tested. Could get it to work with extra resistor to lower high voltage output. IMO not worth the effort.

**Tommycat** · 01-01-2019, 11:44 AM

Two Throttles into One Controller...

Yes, two hall sensor throttles will work nicely on the same controller with no problems.

This is from testing on a Magic Pie V5 internal vector controller and hub motor. With one full (#1)and one thumb (#2) hall sensor throttles. I believe you would get the same results with a mid-drive BLDC motor and controller.

Connecting the sensor inputs and outputs in parallel results in the following data points...

Connections... Controller 5vdc output to both throttle's 5vdc input. Controller 0vdc to both throttle's 0vdc or negative connection. And controllers sensor input connection to both throttle's hall sensor output wire. Up to you how to work it out with HIGO connectors. :-)

Regulated Vin=4.3vdc
Sensor Output Voltage to controller= #1 is .84vdc to 3.44vdc, #2 is .84vdc to 3.41vdc. Start amount did not change from just one. Ending voltage dropped from 3.52vdc with just one.
Total Amperage draw= with 1 throttle is 6.64 to 6.74 mA, with both throttles is 11.38 to 11.54mA. (well within limits)
Motor Start= Stayed the same with one or both at 1.23vdc.

Throttle response was smooth and linear with ether one and almost equal in vdc output, start to WOT. Operating both at the same time seems to have no adverse effects as amp draw and voltage remain constant. As expected the dominant throttle (one with the most voltage output) has control. With nether effecting the operation of the other.

Note: Long term effects at this time are unknown...

**Tommycat** · 10-04-2019, 01:58 PM

Potentiometer Type Throttles...

If unknown, how to know which one you have?:

Both the hall sensor throttle and the Pot. type have three connection wires. If connected to a 5vdc power source, and reading the sensor outputs. With the throttle actuated closed to Wide Open Position. (WOT). The Pot. will output 0vdc to 5vdc, and the hall sensor will output ~.8vdc to ~.4.3vdc.

Also if disconnected from the controller. A Pot will read from it's wiper (or output wire) to ether voltage input/ground connection a varying resistance in relation to it's throttle's handle position. A hall sensor type will not.

Why do you need to know?:

As you see with the differences in voltage outputs. The controller has to be set to expect the type of throttle voltage input that it will receive. Some are programmable and can accept ether input. And others are manufactured to accept one or the other. Looking at the controller's specification sticker will often tell...

As in this example... the "Speed set: 1 - 4.2 volts" indicates a hall sensor type controller.

For example, a problem may occur when trying to use a Pot on a hall sensor type controller. As the low input voltage at start-up would be considered too low and trigger a throttle input safety lock-out. Or conversely, at Wide Open Throttle, it may trip the shorted throttle high voltage cutout...

Why would you care?:

Potentiometer throttles are relatively expensive compared to a hall sensor type. And if you have one I'm sure you'd like to use it. Some find the response from a Pot type to be softer in start-up, smoother, and more preferable over a hall sensor type. To see why, I did a throttle profile on a potentiometer to see what the difference may be. (Note: I was just guessing at the three resistances. As such the starting voltage is too high, and would not be recommended. Just an example of the power curve.)

I was surprised to see the distinctive non-linearity of the Pot as compared to the hall sensor type. With the more gradual uptick at the beginning of throttle actuation, and finishing off strong.

How to make a Potentiometer "look" to a controller like a hall sensor type...

IE: Have the output voltages "mimic" the hall sensor... .8vdc to 4.3vdc, closed to WOT.

As learned in this threads previous installments... a resistor in the ground line will raise the starting voltage. And a resistor in the 5vdc power supply line will lower the WOT voltage. It's recommended to start with a 1 K resistor in each line to get started, adjust as required or desired. As the amperage used is very low (< 10mA) only low wattage resistors are required.

2-17-2020 Feedback from successful pot throttle output modification with resistors required 1K ohms on the 5vdc, and 2K ohms on the ground... YMMV.

**hsapien** · 06-23-2020, 02:38 PM

Hey Cat! Great write up! Am new to this forum and am trying to find out how to make torque sensor type "throttles" communicate with brush motor controllers. The Hall Effect manual throttles seem to be the same for both brush and brush-less motor controllers, so one would think a torque "throttle" based on pedal pressure would output similar to the manual twist or thumb throttle. Cannot find any definite information on whether the torque sensor will work with brush motor and it gets confusing when some forums say the torque sensors are designed for their specific controller interface. Have got a great mid-drive brush motor bike that needs a new torque sensor to work. I could use a manual throttle but would have to use a freewheel in the chain ring of right crank so the pedals won't move unless I want them to. A bit tricky to match pedaling with motor RPM. You seem like the methodical type with patience enough to offer some suggestions. Am sure your many posts have been a great help for Mag Pie and other kit installer-users. All the best,

**hsapien** · 06-26-2020, 06:07 AM

Thanks for the extra information. Will have to get details on how the pedal pressure torque sensor "throttle" compares with the hand throttle...both specs and components to achieve the voltage variances. Looks like a need for a brushless motor controller matched for the BB torque sensor so as to compare with the brush motor controller (using manual throttle on both). There must be someone who's got a shortcut!

**cwenborn** · 11-04-2020, 12:45 AM

Hi Everyone, I have been working on repairing an escooter and my controller and throttle have arrived from Aliexpress now, however I believe I have the issue that my motor is senseless and my controller requires sensors. Is there anyway to bypass the hall sensor?

**Amp Maker** · 12-07-2020, 07:07 AM

Trying a similar approach on a electric Motocross bike.
Thank you, very informative post.

**RadoBG** · 10-20-2021, 03:56 AM

Hey Tommy. I learn a lot from your experimen but I was wondaring if the dobel dipper mod will work from 0-5v sinse I want to use hall sensor insted of an potensiometer. Thenk you for your resurch and time spend on this topik. A hall sensor is 0.8-4.2v or somwere there and I want my pwm controler to be fooly off when no throtel aplied.

**jakesontap** · 01-09-2022, 05:26 AM

Hey Tommycat!! Thanks for the wonderful information!!!
was wondering if you may have a solution or have seen this issue in the past. I have a hall type throttle (LH-100) on a 60v setup. When I release the throttle I have a good second lag where the motors are still getting power before the power is released and she starts decelerating. I have replaced both the throttle display and the motor controllers but problem is still there. Any thoughts? Thanks!!!!!!

Also, if I hit the brake right as I release the throttle the power does stop. This is pretty scary when you are going 40+ mph!! Lol

**jakesontap** · 01-11-2022, 05:58 AM

Do you think if I add a 50k resistor between the signal and ground wire it will drop the signal voltage faster but keep the current pull low? Just trying to figure out how to remove the throttle lag when releasing throttle.
thanks!!!!

**jakesontap** · 01-11-2022, 08:44 AM

Hey AZguy!! I was thinking the same thing but I replaced both the controllers and the throttle and it’s still doing the same thing…? Checked the motors halls with a tester and they checked good.

**Leon** · 04-01-2022, 03:49 AM

Hi Thommycat, I have read your very interesting article on the throttle of the bldc engine. I want to make a cable car from an Electric wheelbarrow wheel, BLDC motor. I want to replace the throttle with a 10k potentiometer. the engine should start up slowly. I want to extend your schematic with the transistor capacitor and potentiometer with a 10 k potentiometer. to set the forward speed. I place a switch in the 5 volt line so as not to have to turn the potentiometer to zero all the time. do you think this will work?

Attached Files

Announcement

Guide to Hall Sensor Throttle operation, testing, and modification.

Guide to Hall Sensor Throttle operation, testing, and modification.

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