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Simple 500w 24v build not working

Captain Qwark

100 µW
Joined
Mar 8, 2024
Messages
7
Location
Belgium
Introduction
First of, this is my first DIY electric anything project, so my apologize if I get things confused or completely wrong. I'm building a cheap 500w electric bike. I thought I chose all the right components but now 2 controller later and I still can't get this simple build done. I'll summarise everything I used as detailed as possible. For people wanting to buy my build, links are down below.

  • DIY Battery
    • 7 series - 8 parallel
    • 2900mAh - 5.8A - 3.6V
    • Voltage of the storage system = 25V
    • Current of the storage system = 46.4A
    • Capacity of the storage system = 23Ah = 584Wh
    • Data Sheet
    • BMS
      • Continuous working current = 20A
      • Charging current = 10A
  • Brushed Motor
    • 500W 24V DC
    • Rated current = 26.7A
    • Data Sheet (I have ZY1020 model but seems to be the same)
  • Motor Controller
    • Rated Voltage = 24V
    • Under-Voltage Protection = 20+-0.5V
    • Speed Regulator = 1-4V
    • Match Motor = 500W

Measurements & facts
When I hand spin the motor I do receive a voltage measurement and this seems to tell me the motor is fine.
When I measure the voltage from the battery I receive a stable 29.1V. I can't test the current as it will blow my 10A fuse in my multimeter. Uses an XT60 connector.
Battery is made with 2x8mm thick 99.6% nickel strips which are spot-welded. Both poles are connected with 14AWG tinned copper wire.

Issues
Problem 1: I don't receive any voltage with the multimeter when increasing the throttle.
Problem 2 (maybe): I can't hear any "click" in both cases when switching the key. The display also doesn't turn of when ignition is off. I used a wire to bridge the contact in between the positive and negative of the power lock on the motor controller which should simulate the ignition turning on, still nothing.

Conclusion
So I assume I must be overloading the motor controllers, causing the fuses of mosfet's to immediately break or the power switch simply doesn't work (I doubt it). Perhaps even the throttle. I'm hoping someone could enlighten me or simply show me all the things I did wrong. I understand that buying everything from AliExpress comes with it's risks but as I'm just a high school student, my budget is quite restrained. The whole project is currently under 250 euro's (100 euro's on batteries).

Complete Project Item List & Buy Links (all from AliExpress unless stated)
 

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Dont know that you should hear any click on turning on the controller fwiw.

have you validated the throttle works as expected the controller ad says it should output 1-4v on its signal wire when provided with 5v..

Do you get +5v at the throttle when the bike is 'turned on'? any positive potential on any of the controller outputs when turned on?
 
Measurements & facts
When I measure the voltage from the battery I receive a stable 29.1V. I can't test the current as it will blow my 10A fuse in my multimeter.
Assuming you're wiring the meter in series with just one side of the battery-to-controller for the current (DC Amps) test, then if the fuse blows when testing current draw out of the battery, it means that something in the system is drawing more than that 10A.

(if the meter is being wired across the battery when measuring curent (DC A) then that's why the fuse blows, because you're shorting the battery with the meter).

If you're not operating the system when this happens, it means that something between the battery + and - is probably shorted, or wired incorrectly.

Your wiring diagram doesn't show any names or functions on the individual wires at each block in the diagram. To know you've got it wired correctly, those are very important. For instance, just knowing you have three wires from throttle to controller doesn't indicate if the red wire is connected to 5v at one end, ground at the ohter, green to ground at one end and signal at the ohter, or if they're wired to the correct things for the actual device pieces. Etc.

Also, when drawing up a wiring diagram for troubleshooting (as opposed to one for building from), dont' go by the charts for whatever youve got. Measure what you *actually wired*--what the actual connections really are, as measured with a multimeter on continuity or ohms with no power to the system. Then with power to the system, measure what voltages you get everywhere, and mark those on the matching points on the diagram.

Most of the time, these steps alone will find the fault, since almost all problems are wiring (either errors or connection faults).


Issues
Problem 1: I don't receive any voltage with the multimeter when increasing the throttle.
If there's no voltage on the throttle signal wire, relative to the throttle ground wire, then either the throttle isn't getting 5v from the controller to power it, or the throttle is defective, or miswired.


Problem 2 (maybe): I can't hear any "click" in both cases when switching the key.
Is there a relay you're using that would cause a click? If so, you need to check the voltage and ground for the coil of the relay, and be sure it's getting what it needs to operate.

If there's no relay, there's not normally going to be a sound, unless the keyswitch itself is designed to click from one position to another. If it is, then it's probably mechanically broken, and you can bypass it by just manually connecting the two wires it is intended to connect, to test the rest of the system, and replace this switch once everything else is working.


The display also doesn't turn of when ignition is off.
What display? There isn't one in your parts list or pictures or wiring diagram. What is the display intended to do, and exactly how is it wired into the system, and what is it's manufacturer wiring diagram?

If you mean the voltmeter built into the keyswitch, if you want it to turn off with the switch you have to wire it so that it's on the controller side of the switch, not the battery side. It's not in your diagram so we can't know how you wired it. ;)
 
Dont know that you should hear any click on turning on the controller fwiw.

have you validated the throttle works as expected the controller ad says it should output 1-4v on its signal wire when provided with 5v..

Do you get +5v at the throttle when the bike is 'turned on'? any positive potential on any of the controller outputs when turned on?
Thanks all the replies. I'll try my best to answer all of them.
I tested both controllers. Controller number 1 shows 4.54V and the second one shows 5.16V. So we can rule that component out I guess.
 

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Assuming you're wiring the meter in series with just one side of the battery-to-controller for the current (DC Amps) test, then if the fuse blows when testing current draw out of the battery, it means that something in the system is drawing more than that 10A.

(if the meter is being wired across the battery when measuring curent (DC A) then that's why the fuse blows, because you're shorting the battery with the meter).

If you're not operating the system when this happens, it means that something between the battery + and - is probably shorted, or wired incorrectly.

Your wiring diagram doesn't show any names or functions on the individual wires at each block in the diagram. To know you've got it wired correctly, those are very important. For instance, just knowing you have three wires from throttle to controller doesn't indicate if the red wire is connected to 5v at one end, ground at the ohter, green to ground at one end and signal at the ohter, or if they're wired to the correct things for the actual device pieces. Etc.

Also, when drawing up a wiring diagram for troubleshooting (as opposed to one for building from), dont' go by the charts for whatever youve got. Measure what you *actually wired*--what the actual connections really are, as measured with a multimeter on continuity or ohms with no power to the system. Then with power to the system, measure what voltages you get everywhere, and mark those on the matching points on the diagram.

Most of the time, these steps alone will find the fault, since almost all problems are wiring (either errors or connection faults).



If there's no voltage on the throttle signal wire, relative to the throttle ground wire, then either the throttle isn't getting 5v from the controller to power it, or the throttle is defective, or miswired.



Is there a relay you're using that would cause a click? If so, you need to check the voltage and ground for the coil of the relay, and be sure it's getting what it needs to operate.

If there's no relay, there's not normally going to be a sound, unless the keyswitch itself is designed to click from one position to another. If it is, then it's probably mechanically broken, and you can bypass it by just manually connecting the two wires it is intended to connect, to test the rest of the system, and replace this switch once everything else is working.



What display? There isn't one in your parts list or pictures or wiring diagram. What is the display intended to do, and exactly how is it wired into the system, and what is it's manufacturer wiring diagram?

If you mean the voltmeter built into the keyswitch, if you want it to turn off with the switch you have to wire it so that it's on the controller side of the switch, not the battery side. It's not in your diagram so we can't know how you wired it. ;)
Sorry I didn't show the display, I added an additional image to the original post. It shows the Amperage, currently 20.6A which makes sense with the 20A BMS inside the battery.
So I think my DIY battery seems to be working correctly.
Also sorry for the lack of detailed schematics but finding data sheets for AliExpress products is quite a challenge.
 
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Sorry I didn't show the display, I added an additional image to the original post. It shows the Amperage, currently 20.6A which makes sense with the 20A BMS inside the battery.
So I think my DIY battery seems to be working correctly.
Also sorry for the lack of detailed schematics but finding data sheets for AliExpress products is quite a challenge.
Why would 20A make sense when the bike is stationary and there is no power to the motor? Are you sure the display is showing battery current and not something else?
 
So power is getting to the controllers, and both drop the battery voltage down to a logic level ok too. SO does the throttle provide voltages between 1 and 4v on its signal wire depending on how open the throttle is? if not then its a bad throttle and needs fixing/replacing.

If the throttle is working as expected.. ?? Brake sensor input is missing from both your diagram and its a detail omitted in both controller ads as far as i could see.. (brief scan)

the second ad lists controller connections among which are some that should provide information.

the there voltage over the wires in the 'indicator' connection that would appears to be a dashboard indicator lamp output?
if so it should provide a positive voltage to light a bulb/led if the controller is on ok..

Also if the brake cut off is engaged and hampering operation you should also find a positive voltage potential on the brake light output too.. and rule out a suspicion i have without any foundation ..
 
Why would 20A make sense when the bike is stationary and there is no power to the motor? Are you sure the display is showing battery current and not something else?
+1 if a voltage display which is the most common simple display metric, thats Awfully close to the low voltage cut off and any drain could result in a voltage sag well below the low voltage cut off threshold.

IF draining 20a standing still something would be burning!!
 
So power is getting to the controllers, and both drop the battery voltage down to a logic level ok too. SO does the throttle provide voltages between 1 and 4v on its signal wire depending on how open the throttle is? if not then its a bad throttle and needs fixing/replacing.

If the throttle is working as expected.. ?? Brake sensor input is missing from both your diagram and its a detail omitted in both controller ads as far as i could see.. (brief scan)

the second ad lists controller connections among which are some that should provide information.

the there voltage over the wires in the 'indicator' connection that would appears to be a dashboard indicator lamp output?
if so it should provide a positive voltage to light a bulb/led if the controller is on ok..

Also if the brake cut off is engaged and hampering operation you should also find a positive voltage potential on the brake light output too.. and rule out a suspicion i have without any foundation ..
Well I omitted the brake sensor from the diagram as it's currently not connected (I have one tho). I know this shouldn't be a problem as I've seen video's were they use the same motor controller without it connecter to a brake sensor and just release the throttle and brake with the normal bike brakes.
 
Can you confirm how the display is connected to the controller, it appears to be via the 2 wire 'lock' connector? And if so My all be it limited understanding of dc electrics is that the reading is highly likely to be a simple voltage reading, and its difference to your pictured battery reading is probably significant.
 
Can you confirm how the display is connected to the controller, it appears to be via the 2 wire 'lock' connector? And if so My all be it limited understanding of dc electrics is that the reading is highly likely to be a simple voltage reading, and its difference to your pictured battery reading is probably significant.
The display/key lock is one unit and has Black/Red/Green wires. The motor controller only allows for the black and Red wires to be connected. The green cable is the ground I assumed and just left it unconnected. I don't think that should be a problem (or I'm a noob and it totally does).
 
So power is getting to the controllers, and both drop the battery voltage down to a logic level ok too. SO does the throttle provide voltages between 1 and 4v on its signal wire depending on how open the throttle is? if not then its a bad throttle and needs fixing/replacing.

If the throttle is working as expected.. ?? Brake sensor input is missing from both your diagram and its a detail omitted in both controller ads as far as i could see.. (brief scan)

the second ad lists controller connections among which are some that should provide information.

the there voltage over the wires in the 'indicator' connection that would appears to be a dashboard indicator lamp output?
if so it should provide a positive voltage to light a bulb/led if the controller is on ok..

Also if the brake cut off is engaged and hampering operation you should also find a positive voltage potential on the brake light output too.. and rule out a suspicion i have without any foundation ..
I think I found it. I tested the voltage on the signal wire and it remained at 1.69V despite me opening the throttle. Could you just check if I wired the multimeter up correctly?
To be clear, the positive and negative wire from the throttle are connected to the multimeter which spans across the positive and signal wire on the motor controller.
Then I did the same but swapped the negative wire with the signal wire from the throttle and connected it just like before to the multimeter. I get 0.8V and no change when throttle applied.
 

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To test the throttle i would plug it in, or supply with circa 5v over the red and black wires following the red=+ black =- convention, and test the voltage between the signal wire and ground Blue/black wires, electric potential is measured against the common ground.

and to test the controllers response a LED or other diode could be used to short the 5v and signal wires dropping the 5v to a level that should run the motor quite fast. (test without motor connected just read the output voltage)


As for the display discrepancy, until its connected up as expected GiGo, But it is a volt meter..
E-Bike Thumb Throttle Power Switch Lock With Key Green Battery Level Display Electric Bicycle
I would guess the green wire is intended to connect to the battery+ve input, and until then is reading wrong? but its guess work i would google it further if i were you.
 
Your pictures don't show all three wires of the throttle fully connected.

First connect the throttle by puting red-red, black-black, and white-blue. Probably should use a plug to make good contact.

a) Power up controller. Put red probe from meter on red lead and black lead of meter on black lead. You should measure 4.5 to 5.0 volts. This shows the thtotle has power.

b) Now move the red voltmeter lead to the blue wire. Keep the black lead on the black wire. As you turn the throttle, the voltage should change form below 1 volts to 4 volts. Make sure the bike won't take off if the wheel moves. Maybe disconnect the chain or have someone hold the bike.
 
Sorry I didn't show the display, I added an additional image to the original post. It shows the Amperage, currently 20.6A which makes sense with the 20A BMS inside the battery.
So I think my DIY battery seems to be working correctly.
If that is a current meter, it should read zero until you engage the motor. If it reads 20.6A with nothing happening, there's going to be a hot spot in your wiring or parts that will tell you where the damaged parts or partial short circuit or miswire is that is draining the battery without moving the motor.
A 20A BMS simply means that the BMS is designed to handle only 20A, and exceeding that may either damage it or if it has an overcurrent limit it would shutdown the output and cut all power, leaving no voltage on it's output, when that 20A is exceeded. There's nothing external on a display like what you have there that would tell you anything about that limit's behavior other than the BMS failing to operate correctly (or at all) in one of a number of ways, or complete power loss once it's exceeded.


If it's a volt meter (the only kind I've ever seen built into a keyswitch or a throttle, so far, in those simple display types), then it means either it is defective and not showing the correct voltage, or your multimeter is not reading the correct voltage, or there is some miswire or interconnect problem between this display and the battery.


Also sorry for the lack of detailed schematics but finding data sheets for AliExpress products is quite a challenge.
The schematics are something *you* draw up as you are building and wiring the system, so that you know what specific wire you connected to what specific place on what specific device. ;)
 
The display/key lock is one unit and has Black/Red/Green wires. The motor controller only allows for the black and Red wires to be connected. The green cable is the ground I assumed and just left it unconnected. I don't think that should be a problem (or I'm a noob and it totally does).
What specifically leads you to this conclusion? (I'm curious as to your thought process, and all of the information that leads you to the conclusion).

What exactly are the functions of each wire on the display/keylock? What is the specific function of the display? (voltage, current, etc). What are the specific functions of the wires you are connecting to the controller?

If you don't know exactly what those are, from documentation that comes with those devices, then how did you determine the functions?

If you haven't determined the functions, and don't have documentation specifying them, what specifically leads you to connect them in the way that they are?


These are things you must figure out when wiring something up (regardless of what kind of equipment it is) to have predictable behavior in an expected way. ;)
 
Your pictures don't show all three wires of the throttle fully connected.

First connect the throttle by puting red-red, black-black, and white-blue. Probably should use a plug to make good contact.

a) Power up controller. Put red probe from meter on red lead and black lead of meter on black lead. You should measure 4.5 to 5.0 volts. This shows the thtotle has power.

b) Now move the red voltmeter lead to the blue wire. Keep the black lead on the black wire. As you turn the throttle, the voltage should change form below 1 volts to 4 volts. Make sure the bike won't take off if the wheel moves. Maybe disconnect the chain or have someone hold the bike.
Thanks for the clear instructions. I did them and here are the results. In the close ups it may look like the cables are loose, but when taking measurements I checked and made sure they were connected.
A) I measured 2.53 volts and 2.73 with full throttle.
B) I measured 0.7 votls and 1.57 with full throttle. The display shows 21.3 and with full throttle 21.6.
There must be something wrong with the throttle then...
 

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