LCD screen backlight flickering

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MarkJohnston   100 W

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LCD screen backlight flickering

Post by MarkJohnston » Sep 04 2021 6:13am

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.
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E-HP   100 MW

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Re: LCD screen backlight flickering

Post by E-HP » Sep 04 2021 11:56am

MarkJohnston wrote:
Sep 04 2021 6:13am
Also sometimes an open circuit still get started and the motor will start spinning. This all happens for no Aparent reason
Can you explain a bit more on what behavior you're describing? Open circuit for what?

MarkJohnston   100 W

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Re: LCD screen backlight flickering

Post by MarkJohnston » Sep 04 2021 12:06pm

The motor just starts spinning. The bike will just start moving. For no reason.

aroundqube   10 kW

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Re: LCD screen backlight flickering

Post by aroundqube » Sep 04 2021 8:01pm

Connectors and display are not 100% waterproof. I would be looking for moisture. Unplug all connectors , dry them out ( hair dryer ,etc) . Reconnect using dielectric grease, being sure pins are good and fully seated. That display has a walk assist function that will turn the motor on. Manual calls it cruise control 6 kph .

markz   100 GW

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Re: LCD screen backlight flickering

Post by markz » Sep 04 2021 8:05pm

^yes

and look for obvious loose connection along with hidden loose connection, meaning wiggle the wires and see what happens.

MarkJohnston   100 W

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Re: LCD screen backlight flickering

Post by MarkJohnston » Sep 06 2021 12:29am

Ok. Im am going to change my twist throttle for a thumb throttle. It's more stealthy and comfortable. When I do this I'll have to cut the zip ties holding the wires to the frame. I'll check each and every wire. I'll check connection too. I have di electric grease for a car battery. But honestly I don't think it's the wiring. I have a gut feeling. What else could it be if it's not the wiring?

99t4   1 kW

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Re: LCD screen backlight flickering

Post by 99t4 » Sep 06 2021 10:07pm

MarkJohnston wrote:
Sep 06 2021 12:29am
But honestly I don't think it's the wiring. I have a gut feeling.
Based on what?
MarkJohnston wrote:
Sep 06 2021 12:29am
What else could it be if it's not the wiring?
The controller.

MarkJohnston   100 W

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Re: LCD screen backlight flickering

Post by MarkJohnston » Sep 06 2021 10:54pm

Because I've been messing around with wires and nothing happens. I just haven't been thorough. I have a spare controller in storage. I'll go pick it up tomorrow and see if it changes anything. Could the LCD be broken too? I read on a separate closed forum that a circuit could be loose in the LCD. Since day TWO of using this kit I've noticed that turning the OFF button on the LCD DOESN'T kill the power. This LCD has ALWAYS been a little off.

MarkJohnston   100 W

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Re: LCD screen backlight flickering

Post by MarkJohnston » Sep 09 2021 12:33am

Ok. It's getting weirder. The LCD back light no longer comes on. It's just a screen with numbers. The head lamp that's connected to the controller flickers on and off. Sometimes there's an open throttle situation. That means that even though I let off the throttle the bike will keep moving. I have to use the brake to shut off the motor.

I checked the wiring. Sometimes tapping on it (the rats nest :lol: ) gets the light to come back on , sometimes not. My sheathing for the motor wiring is broken at the axle outlet. The individual cables themselves do not appear damaged. I taped them up. No change

I TRIED A SPARE CONTROLLER I HAVE AROUND. I stopped using this controller because of another issue. THE PROBLEM PERSISTS. so it's NOT the controller. I plugged in power and LCD only.

What is making this weird stuff happen?

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ZeroEm   10 MW

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Re: LCD screen backlight flickering

Post by ZeroEm » Sep 09 2021 12:44am

by MarkJohnston » Sep 09 2021 12:33am

Ok. It's getting weirder. The LCD back light no longer comes on. It's just a screen with numbers. The head lamp that's connected to the controller flickers on and off. Sometimes there's an open throttle situation. That means that even though I let off the throttle the bike will keep moving. I have to use the brake to shut off the motor.

I checked the wiring. Sometimes tapping on it (the rats nest :lol: ) gets the light to come back on , sometimes not. My sheathing for the motor wiring is broken at the axle outlet. The individual cables themselves do not appear damaged. I taped them up. No change

I TRIED A SPARE CONTROLLER I HAVE AROUND. I stopped using this controller because of another issue. THE PROBLEM PERSISTS. so it's NOT the controller. I plugged in power and LCD only.

What is making this weird stuff happen?
Top
Wonder if your pulling to much power thru the LCD some have limits.
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MarkJohnston   100 W

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Re: LCD screen backlight flickering

Post by MarkJohnston » Sep 09 2021 2:24am

I suppose that's possible but the kit is rated for 1000 watts. That's what's being pumped though.

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ZeroEm   10 MW

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Re: LCD screen backlight flickering

Post by ZeroEm » Sep 09 2021 11:30am

Did not mean for the motor. Just the extras. I know mine has a limit so use DC to DC stepdown. Don't think you run the extras all the time, so it was just a thought. Must be a bad connection in the LCD.
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MarkJohnston   100 W

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Re: LCD screen backlight flickering

Post by MarkJohnston » Sep 09 2021 11:43pm

Here's the info for the kit. Originally I had one battery hooked up to the kit. That battery was 48 volt, technically 54 volt 10.5 Amps. If you read this picture is says you CANT use a battery with LESS THAN 11.6 AMPS. This is true. When you try and run it with less than 1000 watts there is sag especially on hills. Literally the whole thing just shuts off. Not enough power.

So I had a second battery of the SAME CELLS,SAME QUALITY, SAME VOLTAGE, and just string them in parallel. I designed a harness for this that's pretty much as good as anything from tech has to offer from stuff on ali express.

Ok then I stopped having that problem BUT right after I plugged in the NEW PARALLEL SET UP I noticed that the system is ALWAYS LIVE. I.E. THE POWER BUTTON on the LCD does not shut down the throttle. Unless you pull the plug someone could walk up twist the throttle and get the wheel to spin while you are in the grocery store or whatever. Seems like doing that with TWO batteries broke the LCD.BUT THAT WAS 5000 MILES AGO! weird that problems would arise now from over watt. Also read the specs. It needs a big battery
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MarkJohnston   100 W

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Re: LCD screen backlight flickering

Post by MarkJohnston » Sep 10 2021 12:27am

By the way I do the run the extra nearly all the time. The controller has a wire for the light. I do day light running light. I always have that head lamp on. Always. It is rated for 60 volts 20 amps. Its a motor cycle headlamp you can get here on ali express. Check the picture.

Maybe using that light is doing this? It draws a ton of power. Very bright.
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ZeroEm   10 MW

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Re: LCD screen backlight flickering

Post by ZeroEm » Sep 10 2021 12:48am

One way to find out don't use it for a while. Running batteries in parallel should not bother. Its just more amps unless you bypassed something.
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MarkJohnston   100 W

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Re: LCD screen backlight flickering

Post by MarkJohnston » Sep 10 2021 3:29am

I just noticed there is lots of dirt and grit in one of the connectors for the light. Is this potentially the problem? Definitely pushing on the phase wires is making stuff go hay wire. I'll get some pictures here soon of any potential problem points for you guys to diagnose.

MarkJohnston   100 W

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Re: LCD screen backlight flickering

Post by MarkJohnston » Sep 10 2021 5:48am

Ok

It just rained in LA and it hasn't rained in 6 months at least. But I just noticed condensation gathering inside the LCD.i guess this kit isn't nearly as water proof as I thought. I wonder if this could cause serious problems ? See the picture

Also where my motor axle wiring exists the axle the outer sheathing has been chewed away. Could this be the source of the problem? What happens if wires rub inside there? See the picture of that as well
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MarkJohnston   100 W

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Re: LCD screen backlight flickering

Post by MarkJohnston » Sep 10 2021 6:33am

Here I am outlining potential causes to the problem

1) MY phase wires melted their insulation a bit. I had shoved them into that little bag to hold wires but it just got way way too hot in there. This is a common problem with this kit. But they still work and there is a metal to metal connection. I added some electrical tape. I can still hook and unhook these. Nothing feels loose here, but I guess I could be wrong about this being ok.

2) The controller is mounted underneath the rack. The reason being is that before a controller burnt out with a shorted MCU either by being inside a pannier and getting to hot or because of RF interference. However now that the controller is mounted UNDERNEATH THE RACK I am not sure if this is allowing WATER TO GET inside. Please note I live in a very dry climate, Los Angeles. it hardly rains here and it rained once like 6 months ago. This year it has not rained at all, except for tonight. I felt this was the best way to be STEATHLY but also allow some WIND to hit this thing to cool it off. Especially the wires and the THREE phase wires. There is a rubber pad where the wires go in if you look close enough in the picture. That being said perhaps water from a couple of puddles when it rained months ago finally got to some of the wires? Yes this controller did get a little wet tonight from the very light rain. the top part where the wires are did not get wet because I covered it. I guess I could reverse the rack so that the knobbies don't flick water directly at the silicon gasket or whatever but then the wires would be a heck of a lot more noticeable to any police man behind me.

Oh yeah I also had green tire slime geyser out when a big chunk of glass got imbedded in my wheel. that stufff went all over the controller but i dont think it would've been able to get inside. It's the green stuff that keeps you from getting flats but it doesn't always work as you see here :x

Yes I did unplug and unplug and replug every connector no dice. Im still having intermittent issues. ELECTRICAL GREMLINS! GREMLINS! AHHHH :evil:
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ZeroEm   10 MW

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Re: LCD screen backlight flickering

Post by ZeroEm » Sep 10 2021 11:10am

Most things are not water proof unless you can take it under water and it still works even then it has a depth rating. Most things are water resistant but they need help. Wiring should have a sag or drip loop so water will not follow the wires in and drip off. You can add extra sealant but water is hard to stop. Just guide the water away.
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MarkJohnston   100 W

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Re: LCD screen backlight flickering

Post by MarkJohnston » Sep 10 2021 8:02pm

Zero em. Should I design a screen guard to get water to not splash where the wires come out of the controller ? If so, how do I do this?

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ZeroEm   10 MW

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Re: LCD screen backlight flickering

Post by ZeroEm » Sep 10 2021 9:01pm

I would just try to seal it better after it's completely dry. If you have water streaming from the front wheel then a guard (fender) between the tire and LCD would be good. As with most things that get wet after a while you will need to clean connections.

You need to replace or repair any bad wiring, vinyl tape, heat shrink. If the wire are overheated and melted they need to be traced and make sure you don't have anymore shorts. It would explain the trouble.
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MarkJohnston   100 W

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Re: LCD screen backlight flickering

Post by MarkJohnston » Sep 10 2021 11:57pm

Ok. I'll redo the phase connectors and the light where there is cracked / dirty connections. The knobbies on the front are kicking up water to my legs. The tires on the back kicks up water towards the controller since it's under the rack

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Re: LCD screen backlight flickering

Post by MarkJohnston » Sep 15 2021 1:35am

Well, I went ahead and just stuck the controller on top of the rack and flipped it. I also redid the gritty nasty connections for the head light and the phase wires. Hopefully that fixes the intermittent open throttle situation.

It's less stealthy but I've already got big old phase wires sticking out. The phase wires on this get INCREDIBLY HOT. None of my connectors are rated for 1100 WATTS they're all from home Depot and meant for household use. The connectors keep melting. Even solder using the XT90s kept melting. These things get so damn hot. It's insane. maybe a good reason not to buy a cheap Chinese hub motor.

Definitely not stealthy from behind :cry: oh well. Looks those puddles and that rain from 6 months ago eventually fried the LCD backlight it won't come back on. You have to be really careful you put the damn controller!

A splash guard just doesn't make sense for me here in LA. just wasted weight.
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markz   100 GW

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Re: LCD screen backlight flickering

Post by markz » Sep 15 2021 1:49am

Now thats a first
Using a 2 pad locks to secure the controller to the rack.

Splash mud guard - When it rained on the weekend while I was riding I used cardboard from the back of a store and used electrical tape to secure to the rack.
When I got home I cut up some plastic to the shape of the rear rack and used Gorilla Tape. I since moved the square battery from triangle to rear rack but its not ideal as over time the weight will damage the rear rack or the bike will fall putting a twisting force on rack mounts and break sooner or later.

MarkJohnston   100 W

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Re: LCD screen backlight flickering

Post by MarkJohnston » Sep 15 2021 4:49am

markz wrote:
Sep 15 2021 1:49am
Now thats a first
Using a 2 pad locks to secure the controller to the rack.



I since moved the square battery from triangle to rear rack but its not ideal as over time the weight will damage the rear rack or the bike will fall putting a twisting force on rack mounts and break sooner or later.
The padlocks because we have so many dumb ass thieves around here who will think the controller is the battery, pull out their nasty wire cutters and have at it. Sadly I wondering how to WIRE CUT PROOF all the wires because more than likely these scum bags they will only succeed in vandalizing and ruining this stuff. LA is the worst with bike thieves and the like. It's mostly street crack heads. Our mayor is worthless and doesn't care, much like most place in America when it comes to bikes and ebikes.

Right the batteries are extremely heavy. I've already snapped a cheap aluminum rack. Now I have this Bontrager one and it will snap too at some point. Funny I've never had rack mounts brake even in crashes where I totaled the bike. I hit a car on my steel tour/road bike conversion. The only way to somewhat win is a stainless steer touring rack by Tubus, but it costs a fortune at $170. I already forked out $300 for the panniers. Bags get stolen off bikes all the time in here especially near the beach.

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