LCD screen backlight flickering

MarkJohnston

10 kW
Joined
Mar 25, 2021
Messages
620
Hello,

I have a very strange problem. My LCD the SW900 is flickering on and off. The SW900 is a fairly generic LCD that comes in a lot of the ebikeling kits. The back light for the LCD keeps coming off and on but you can still read the LCD just no light to help.

Not only this, but the light I have plugged into the controller sometimes shuts off it's the front light, but it only turns off for a few seconds. Also sometimes an open circuit still get started and the motor will start spinning. This all happens for no Aparent reason

You can see in the pictures with the LCD, I am not changing settings, it just does this.
 

Attachments

  • PXL_20210904_053648388.jpg
    PXL_20210904_053648388.jpg
    186.3 KB · Views: 1,157
  • PXL_20210904_030842257.jpg
    PXL_20210904_030842257.jpg
    298.5 KB · Views: 1,157
  • PXL_20210904_030848289.jpg
    PXL_20210904_030848289.jpg
    204 KB · Views: 1,157
I need to fix this cut wire at the axle. I checked the wire and the small hall green wires insulation has peeled away substantially. It's about to touch the small black hall wire!!

I noticed that now there is an open throttle situation a lot. I'll turn the throttle and LET GO but it'll keep going by itself!!! Thankfully I have a brake sensor cut off. Maybe the throttle itself is causing this problem. It's coming off the handle bar! See the picture.

Should I even ride the bike? What's the worse thing that could happen if those wires touch? Should I just unplug the hall sensor and go sensor less until the part arrives? Could I potentially damage something here?

Any time I hit a big bump and the bike is running by itself , i.e. an open circuit, then suddenly it stops! Honestly seems like something is loose inside the LCD, or it's the axle wiring slash/cut/
 

Attachments

  • PXL_20210919_033539830.jpg
    PXL_20210919_033539830.jpg
    189.7 KB · Views: 1,107
ZeroEm said:
I would not ride with wires shorting out or throttle staying open. Sounds like some moisture issues. It seems lately that more and more members are having to dry out there components and reseal them.

It could be, water could've to gotten inside the throttle, LCD, and maybe in the axle wiring.

A replacement throttle is on its way from Ali baba, takes a long time though.

Odd... It's so so dry here, i.e. zero humidity. It rained like a week ago, and before that six months ago.
 
ZeroEm said:
Had taken that this started after a rain. Will reread your thread. Don't always have the focus I should have.

It's ok. Any help is appreciated. :eek:

No this problem started in August and has gradually has gotten worse.
 
Would find out home much power your allowed to pull thru the LCD and try to stick to that. Would think it's the LCD. Sometimes grounding is an issue. Make sure nothing is grounding to the frame. I'm at a loss if beyond that.
 
ZeroEm said:
Would find out home much power your allowed to pull thru the LCD and try to stick to that. Would think it's the LCD. Sometimes grounding is an issue. Make sure nothing is grounding to the frame. I'm at a loss if beyond that.

Zero, the LCD has a setting or 48 volts. My battery is 54.6 fully charged. Maybe that's why. The kit is designed for a 48 volt battery.
 
I would not focus on the Volts. You need to be in the correct voltage range, which seems you are.
Don't have any ideas at the moment. Hope someone chimes in. With a better idea.

Have running lights, and rear light. For the front bought a pair of motorcycle fog lights and using one at the moment. Don't think i'm using more that 3a. Could try to power it all thru the display, have chosen not to. Hooked up a Dc Dc converter to power it all. Even have a USB port I can add when needed.

Don't worry about the 48v that is just advertising. it's really a range 39v - 54.6v. Most things in this range are good up to 60v. This is only to guide a person. You need the spec's on a device to know for sure.
 
Was going to mention about your batteries. Some batteries with a off switch. When charging even when switched off, will power up the BMS and LCD. This sounds like you connecting two batteries together. Some how it like turning on the switch.
 
ZeroEm said:
Was going to mention about your batteries. Some batteries with a off switch. When charging even when switched off, will power up the BMS and LCD. This sounds like you connecting two batteries together. Some how it like turning on the switch.

Yeah there is an on off button on the LCD. But it is useless. All I need to do is plug in the battery and it's always live. The on/off just turns off the LCD. Except for day one of testing the kit! I couldn't figure out how to turn it on! I had to ask vendor to tell me how. Long press the M button! Now I know, but oddly every since there's always power to the motor no matter what.

I always unplug the two batteries and charge separately with two different chargers. I never charge in parallel to play it on the safe side.

I think something is loose inside the LCD. OH! also my open throttle/ run off bike stopped after I taped up the axle wiring. I think the pannier was hitting the axle wiring on big bumps and that wore a big hole in it. The big green phase wire was shorting onto the black hall sensor. It must've fried the LED screen back luminescence. Now it's just black and white. :x
 
by MarkJohnston » Oct 04 2021 5:01am

I think something is loose inside the LCD. OH! also my open throttle/ run off bike stopped after I taped up the axle wiring. I think the pannier was hitting the axle wiring on big bumps and that wore a big hole in it. The big green phase wire was shorting onto the black hall sensor. It must've fried the LED screen back luminescence. Now it's just black and white. :x

Axel wires and throttle having todo with each other. Don't see the connection. The LCD that makes sense. Hope it is now running ok now. Nothing like getting to know your e-bike.

Have two battery chargers for my e-trike. Decided to adjust them, both are set to high and always keep a close eye on the charging and cut it off. One charger is to use for regular charging to 80%. Opened it up and it would not adjust until I figured out was trying to adjust the wrong thing. Supposed to have one trim pot but my chargers have three. Now I need to figure out what I did to it. This charger was 1v higher so never have used it. I'm going to guess that what ever I adjusted was not set correctly to start with. Think it will be safe to use. Only going to 80% and trim pots are for fine tuning.
 
Now some of the numbers are fading. It's starting to fail. Any recommendations for a new LCD? The controller requires an LCD.not sure if it has to be this one though
 
The short answer is buy the same LCD and make sure the pinouts/cables are the same. Guessing and trying out wires are bad. Power to data cable could end the life of the LCD.

I'm no help with these. I know they are setup for specific controller. Helped my brother with his. Don't run them myself, Like the CA. Have found some threads on this one but don't seem very helpful. I will keep looking!
 
"Product Information

Product name: LCD Control Panel
Color: Black
Material: LCD, Plastic
Voltage: 48V
Power: 1000W
Suitable for: Voilamart Electric Bicycle Conversion Kit"

Found a replacement, same thing,

I am putting 1200 watts through the whole system for LCD meant for 1000 watts. did I find the source of the problem?
 
Would not focus on the watts. The controller is rated for amps.
The watts or amps do not go thru the LCD.
The LCD would be match to the controller and they would have a voltage range.
With motors it's the heat. The amps can melt wires if using to many.

Hoping some would chime in on your display. There are a few types that are common. I just don't know them.
 
Can a tiny bit of corrosion on the wires cause this? I found a couple nicks in the insulation, and heat shrinked it up. It was the light with the thinly insulated wire
 
Short answer is I don't know. Some controllers are wired for the CA, if you have one of these then yes.

I would not think, the CA is not the same thing as a regular display. LCD's are built for specific controllers to to send signals to the controller to modify it's behavior. The CA only modifies the the throttle input to the controller, does not interact like an LCD for the controller.

You can check out the wiring pinouts from the CA guide. The CA only monitors how much power the controller is using, then modifies the throttle input. To hook one up all you need is to hook to the controller shunt or add one inline.
 
Great. I just fried my new controller that I just paid $60 for. :oops: ... I was messing around with the wires and forgot I had my positive battery cable connected to the controller. My negative cable ever so slightly brushed against my light cable and "pop" ions, and now error 10 on the SW900 meaning controller error, can
t communicate with controller. :oops: It's destroyed. I just walked miles to get back angry and pissed off at myself. i think I blew my light as well, it's very faint.

I have another controller (same kind/ model/manu). that one I f'ed up too by being an idiot and shoving it in my panniers to be more stealthy. At least that one runs in sensorless mode. i.e. something fried part of the MCU. ITS SO LOUD. I am going to use that for a back up for a little bit.

In the mean time I want to take this time to upgrade. My axle wiring needs to be re done. I am look ing at the grin tech cable for that. There's a little bit of extra room it seems like inside my axle bore to SQUEEZE that cable through like grin does.Hope fully it works.

At the same time maybe I should purchase an (Cycle analyst) CA-DP for direct drive motor, as well as controller that will DEFINITLEY work with it. Also a controller that already has a soldered L1019 grin tech anderson cable in it would be good as well. Lots of money going into this... :x
 
it's looking like I may have fried the LCD actually. I just tried to use my back up controller and it won't work. this LCD and controller set up won't work without the LCD unfortunately.
 
REading the video comments

"error 10 means that the display cannot get data from the controller that it is supposed to be connected to .it is a communication issue . this can be caused by a break in the connections(data and power) like a cable or a connector ,or that the connected controller is not powered up through the main power or 25-60 v enable line ..i have found that one of the reasons for failure is too much current is taken via the switched display out to the controller ,overloaded by people connecting current hungry lights ect.error 10 means that the display cannot get data from the controller that it is supposed to be connected to .it is a communication issue . this can be caused by a break in the connections(data and power) like a cable or a connector ,or that the connected controller is not powered up through the main power or 25-60 v enable line ..i have found that one of the reasons for failure is too much current is taken via the switched display out to the controller ,overloaded by people connecting current hungry lights ect."

Maybe the light was guzzling the current? I checked the current and 54.6 volts were being funneled to that light. That light can draw up to 100 volts or something crazy. it meant for a motorcycle. its the very definition of current hungry light.
 
Here is a picture of the internal. I need a precision screw driver to go any further, but if you ask me the damage here is invisible. probably RF. There is a little bit of black glue used to adhere the two peices of the display together. It's ON the circuit board. look for it.

Any ideas what to jumper together, or what to do just so I can spin the motor up. This controller requires the LCD to be on and WORKING. what a load of rubbish. Pretty sure this is toasted after my little mistake. I just bought another one for $40 :x. It's coming on the ALi baba, just gotta wait, well see.

I saw a generic controller on ALI for $20. i also saw a controller on grin tech for $140. The grins are sold out but I am sure are higher quality. how long do you think a $20 generic would last. DOES A BETTER CONTROLLER MANAGE BATTERY LIFE BETTER? dOES IT?

Check out this Ali controller

https://www.aliexpress.com/item/4000346863611.html?spm=a2g0o.productlist.0.0.d9b66096IROdw5&algo_pvid=c7572b0d-d3fd-4f2a-b4be-5bbf26da49ab&algo_exp_id=c7572b0d-d3fd-4f2a-b4be-5bbf26da49ab-37&pdp_ext_f=%7B%22sku_id%22%3A%2210000001430495532%22%7D

Damn, this is becoming a part time job with all the stuff breaking lately, I might just have to throw in the towel here soon...
 

Attachments

  • PXL_20211021_113512240[1].jpg
    PXL_20211021_113512240[1].jpg
    435.1 KB · Views: 239
  • PXL_20211021_113541140[1].jpg
    PXL_20211021_113541140[1].jpg
    377.4 KB · Views: 239
Back
Top