Diagnosing Controller w/ Ebike Tester

Hey All -

I'm trying to figure out what's wrong with my ebike and I've hit a wall - hoping someone here could point in the right direction. My ebike isn't turning on and so I bought an ebike tester and it looked like the problem was the controller - everything else tested and was working but no lights with the controller. So I bought another controller - but the same thing happens, no lights. I've tested the motor, throttle, brakes, and the battery voltage - they all look good.

Is it possible I have two broken controllers? Is there anything else I can try?

Thanks!

Mike

if you upload pictures it helps, new controller blown? anythings possible. exact same controller?
whats not lighting up, the display?

you haven't changed your battery recently right?

I'll upload pictures shortly but yeah the second controller is the same model. Using the ebike tester with the controller and throttle, i'm not getting any of the AABBCC lights which I think are supposed to flash and spin in a circle when you turn the throttle. I haven't changed the battery recently, but the battery charge indicator light stopped working around the same time. The voltage coming out of the battery looks good though so I think the battery is good.

is the battery charge indicator light part of the throttle or on the battery. maybe you blew a fuse inside the battery case or in the bms but PICTURES someone might help you.

When you plugged the controller into the tester did the center led light up in middle of the circular group of 6 led's? If you don't see that, there's no 5V power running the Hall sensors in the 2x3 molex plug.

You can check the red and black wire on that same plug with a voltmeter to verify.

If there's no 5 volt power on both the new and old controller, it's more likely that whatever turns on your controller, a handlebar switch attached to the LCD or LED, or a switch attached to the throttle ...those switches or the wire harness are not working to turn on your controller (new or old).

Since you haven't described your bike, you have to post some pics, including some that shows how the bike turns on, Maybe the connector from the display or throttle too. Then you might get some help tracing the circuit that turns on the controller to makes sure it works.

Are you measuring the battery voltage while it is connected to the controller?

Or when it is not connected to anything?

The former should give a correct reading. The latter may appear correct, but in actuality be leakage thru the shut-off output of the BMS, which will go away once a load is placed on it.

Thanks for the replies! The battery indicator that no longer works was part of the battery itself. If the BMS is the problem on the battery would you still be able to read a voltage? I was taking the reading from the battery directly - which wires would give you the voltage from the controller?

I attached a picture of my testing setup. The 5v light is in a different place - but it wasn't lighting up either. I'm also using a new throttle - one that only has 3 wires (red/black/green) instead of 6 and no on/off switch like the previous one. Seems like that might be the issue?

Yikes. You gotta replicate the on off switch. The old one had six wires?

One is going to be your battery power. Another one will probably get switched to battery power when the on/off is switched, I don't know what the third one would do. A picture of your throttle is needed.

Connect the old throttle back up and turn it on. Use your voltmeter to find the battery wire and also to find the second wire that gets switched to power. To keep your controller turned on, jumoing those two wires should do it. You could add a switch too.

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docw009 said:

Yikes. You gotta replicate the on off switch. The old one had six wires?

One is going to be your battery power. Another one will probably get switched to battery power when the on/off is switched, I don't know what the third one would do. A picture of your throttle is needed.

Connect the old throttle back up and turn it on. Use your voltmeter to find the battery wire and also to find the second wire that gets switched to power. To keep your controller turned on, jumoing those two wires should do it. You could add a switch too.

Click to expand...

+1 You probably have 2 good controllers and just weren't turning them on. To verify it is turning on, measure to see if about 5V is going to the throttle. If the throttle is getting voltage, then check that your battery voltage is within the operating range of the controller, ie less than the high voltage cutoff and more than the low voltage cutoff. If that's not the issue, then make sure the ebrake cutoff isn't the issue.

Did you check the motor phases and hall sensors with the tester, as well as the throttle? I like to do the easy stuff first while going through the process of elimination to find problems.

When I measure the throttle from the controller plugged into the tester I get 4.8V going to the throttle. I think i've tested the battery voltage as well and it was coming up around 30V - i'm going to double check that. Also tested the motor hall sensors and that seems to be working too.

Yeah the last throttle had six wires - that throttle definitely is broken so sadly I can't use it to test. I ordered another throttle with an on/off switch that should be here soon though - hopefully that's the issue. Thanks again for the super helpful info!

Well I got a new throttle with an on/off switch but it appears I got a lemon. Does this throttle wiring look correct to you guys? I'm wondering if maybe the colors on the controller and tester wires are different than the throttle. Otherwise I'm gonna send this one back and get a replacement.

Okay so I got a replacement throttle that works and I connected and tested everything. I found out I was not testing the controller correctly in the first place - apparently you need to have the battery connected in order for the testing device to work - you can't test the controller alone. At any rate when connecting the battery to the controller and then to the tester - I'm not actually getting 5v from the controller. Does that mean the controller is busted? Maybe I just got a lemon of a replacement?

A summary of what i've learned so far:

1. You need to have the battery connected to the controller in order to test the controller
2. There is a 5v light on the tester that should light up when connecting the controller/battery to the tester
3. Some controllers need to be turned on before you can use them, so testing a throttle without an on/off switch won't work if you have that kind of controller (which I do)
4. Controllers and throttles have different wiring configurations (unless they come in a package) and you'll need to look at a wiring diagram to figure out which connectors go where

This is the tester being used
https://www.ebay.com/itm/24V-36V-48V-60V-72V-Electro-Car-E-bike-Scooter-Motor-Controller-Tester-US

30v battery voltage? That's below the LVC on many 36v controller.

I just measured it again and i'm getting 40v - not sure what was going on before or if that was a typo