trying to repair an e-bike

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Vixsiuol   1 µW

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trying to repair an e-bike

Post by Vixsiuol » Feb 20 2018 5:22am

Hi, I would like to repair a friends e-bike (and in the mean time learn a bit about e-bikes). I've got some basic knowledge about electronics, but I'm certainly no expert. So if anyone can give me some advise how to get started ...

I know there's been a short circuit in the connector between the display and the controller (and I have the impression that somehow the battery is connected directly to the display??).

I've connected the display's wires one by one omitting the connector and it gives an error 30 (Abnormal Communication, supposedly). I also think that the display warms slightly when the battery is connected.

Now, I'd like to find out whether:
1) the display and/or the controller is/are broken?
2) if I need to change the display, do I need exactly the same or are there compatible displays?

The display is a King Meter J-LCD (http://www.kingmeters.com/project/j-lcd-display/)

On the controller's print there's a serial number: LSW6G-96A-1-111117 (and a date 2011-11-17)

There's also a label on the controller's housing, which is only partially readable, it says:

Controller for brushless ...
rated voltage 36V
maximum current 10A(?)
rated current 6A
low voltage protection 31...
throttle adjustment voltage 1.2 - 4.4
product number 781-22-5 X130H(?)
ex factory date ...
CE:G3M...1-158...

I measured the cables connecting the controller and display, motor, brake sensors and battery and at least they seem to be alright.
I found an e-book "build your own electric bicycle" (Matthew Slinn) which seems to contain some information on measuring a few things in the controller. So that's what I plan to try next, but any tips and hints are welcome.

Gerrit

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amberwolf   100 GW

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Re: trying to repair an e-bike

Post by amberwolf » Feb 20 2018 2:34pm

Vixsiuol wrote:
Feb 20 2018 5:22am
I know there's been a short circuit in the connector between the display and the controller
If there was a short between the battery voltage (which is on at least two pins) and the data lines, it could've destroyed the data communications chips in both display and controller, which means neither one will ever be able to talk to the other. If the system requires comm to happen before it will operate, you'd need to replace both of them.

It's possible there is a manual for the system online, maybe here on ES, under Li Shui, Lishui, Kingmeter, King Meter, etc. but it's probably going to be model-specific. They dont' all work with each other or work teh same way even when they do.

Now, I'd like to find out whether:
1) the display and/or the controller is/are broken?
The only easy way to check without something to "sniff" the data and see if anything is being sent and received is to swap out the LCD and/or controller and see what happens.
2) if I need to change the display, do I need exactly the same or are there compatible displays?
Usually the displays are not compatible between different brands, but some of the *same* brand but different model will work (but not always). Best is to just get the exact same model if you replace just one part.

If you replace both then you can just make sure they are a matched pair (kit).


I found an e-book "build your own electric bicycle" (Matthew Slinn) which seems to contain some information on measuring a few things in the controller. So that's what I plan to try next, but any tips and hints are welcome.
http://ebikes.ca has a troubleshooting section that helps with a lot of things, but in your case the comm error is almost certainly between LCD and controller, and if the connections are all good, and are correct, then the short that occured between wires there probably damaged something in both units.

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Re: trying to repair an e-bike. King Meter J-LCD

Post by mirrabucca » Apr 16 2018 6:34am

Hi.

Good luck with your quest. Although to your credit you did get a reply!

I have the same (or similar?) system on an E-Bike I bought recently. It was junked and the price was very low - worth buying for any parts that were good.

The LCD (a King Meter J-LCD) was damaged, but the control functions still worked. The bike had been torn apart (by kids by the look of it) and most parts were broken. Never the less, when I assembled the bike, it ran ok. The front fork drops had been chewed out, all connectors had been disconnected, brake and gear cables disconnected. but as I said, all worked except the LCD, once I assembled it.
The battery, a 36Volt 15Amp unit is good. Measured 43 Volts.
Unfortunately, the controller has an intermittent fault that appears to have gone "solid". So I am looking for a replacement.
Trouble is, there doesn't seem to be a way of finding what controllers will work with the J-LCD.
It will post a separate post on my repair investigations soon.

Jeff

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amberwolf   100 GW

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Re: trying to repair an e-bike

Post by amberwolf » Apr 16 2018 4:11pm

Intermittent probelmes are almost always wiring issues, so since its not intermittent anymore it should acutally be easier to find. Use a multimeter on Continuity setting, with a beeper, and its easy to test all the wries from contact tip all the way back to the PCB inside the components.

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Re: trying to repair an e-bike

Post by torker » Apr 17 2018 6:32am

Pics would be great. Also if it is the controller it might be easier to replace it. Others should know how cheap they are.
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