Need help wiring thumb throttle for MP3

[Cgar]

Hi everyone,

I'm new to ebikes. I purchased myself a MP3. I need guidance on how to wire this wuxing 48v thumb throttle. Here's a picture of the wiring:



Top or left wiring is from the thumb throttle

Where do I connect the Red and Yellow wires ?

Thank you in advance

[Bikemad]

Hi Cgar andto the forum.

Unfortunately it may not be as simple as you think because the different throttles are unlikely to use the same coloured wires for the same functions.
The green wire on one may be a battery feed supplying the battery gauge on one throttle, but could be a +5V supply for the hall sensor on the other.
It looks like you will have to dismantle the thumb throttle to find out where the various wires are connected.

If you look closely at the throttle you will see the thumb lever part is held in by three lugs in the centre.
Hold the throttle housing in your left hand so that the lever sticks out to the right.
Put your right forefinger under the lever and gently prise it upwards while pushing the lug nearest the lever towards the centre of the hole with your thumb. (This is complicated to describe but very simple to do)
The lever assembly should spring out once it has been released from the retaining lug and can then be removed along with the return spring.
Undo the small cross head screw and remove the cover so that you can see the wiring connections:



To reassemble the throttle first refit the plastic cover and the retaining screw.
Then locate the end of the return spring in the small hole shown in the above picture (not the slightly larger hole next to the grub screw in the fixing clamp) and make sure it goes fully into the hole.
Then carefully twist the lever assembly half a turn in an anticlockwise direction to pre-tension the spring and then gently clip the lever assembly back into its original position. If it is lined up properly it should clip in very easily without having to force it.

When you have mastered the technique the lever assembly can be removed completely and refitted again in under 10 seconds.

Wiring connections
Take a good look at your wires inside the throttle and see which connections are identical to mine and which are different.
All wires that are identical to mine (same colour and connected to the same connections) can simply be joined to their matching wires on your harness, but any that are different will need to be carefully matched up to the correct function rather than the matching coloured wires.

Your thumb throttle will only have two wires connected to the switch (possibly Brown and Yellow) and a separate wire connected to (or even instead of) the red wire on the battery gauge.
Instead of altering the wiring inside the throttle, it might be easier to simply join the required wires externally but you will need to determine which colours need to be swapped.
Two of the wires coming from the throttle will both need to connect to the battery supply wire (orange?)

If you are unable to work out the necessary connections, post some details of your wiring (pictures are always helpful) and I'll see what I can do to help.

Alan
 

[Cgar]

thank you alan!

This is was REALLY helpful and I never thought of removing the enclosure.

As of now, my thumb throttle is working but still wondering if the battery indicator is really working or not.. because I still havent seen the high level LED step down or turn off. If it doesn't then i'll have to remove it and see what the wiring is inside. I will post and send pics if I am having problems.

Again, sorry about the VPN/IP Issue!

[Bikemad]

My thumb throttle is working but still wondering if the battery indicator is really working or not.. because I still havent seen the high level LED step down or turn off. If it doesn't then i'll have to remove it and see what the wiring is inside.

If the three LEDs are lighting up then the gauge is definitely connected up correctly.

Your throttle should have 48V printed on the casing, if it does not have this on it it may be a 36V throttle:

My experience with the throttle is, that all LED's are ON during the whole time and the last 500 meteres of driving with batterie power one after the other is going OFF.
So the functionality of this voltage-watcher is not very useful.

This basic LED battery gauge was originally designed for lead acid type batteries which have a more pronounced voltage drop throughout their discharge, but the LiFePO₄ batteries in use today have a higher voltage which drops very little in comparison as they discharge, and the LEDs would probably remain fully lit for 90-95% of the battery's use.



Take a look at this post to find out how a resistor can be used to adjust the gauge operation to better suit the battery type being used. As your cable has already been chopped it should be relatively easy to solder a variable resistor into the battery gauge power supply wire.

Alan