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4 foot LED lights flickering

Kart31

Member
I recently had to change to 4 foot LED lights (because I could not find any replacement flourescent fixtures). When the washing machine runs, they flicker. Any thoughts on the cause (beyond the fact the washing machine is running) and anything I can do to get them to stop?
 
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gophert

Well-Known Member
Most Helpful Member
anything I can do to get them to stop?
Turn off the lights or turn off the washing machine.
you can also open up the light and put in a larger capacitor - or make sure the existing capacitor in there really works.
 

gophert

Well-Known Member
Most Helpful Member
What else have you ruled out as a possible cause so we don't offend you by rehashing already-explored possible solutions?
 

Nigel Goodwin

Super Moderator
Most Helpful Member
I recently had to change to 4 foot LED lights (because I could not find any replacement flourescent fixtures). When the washing machine runs, they flicker. Any thoughts on the cause (beyond the fact the washing machine is running) and anything I can do to get them to stop?
Where are you?, sounds like your electrical infrastructure may be rather poor?.

Also, what LED lights are you actually using?. If they are fluorescent tube replacements, and you modify the fittings accordingly, then they are normally perfect.

Are your LED's dimmable?, if so and your electrical supply is very poor, then their brightness will vary as your supply drops under load - non-dimmable ones maintain their voltage, so don't vary.
 

Kart31

Member
Where are you?, sounds like your electrical infrastructure may be rather poor?.
In the US

Also, what LED lights are you actually using?. If they are fluorescent tube replacements, and you modify the fittings accordingly, then they are normally perfect.
These are direct 4 foot LED light fixtures. The "bulbs" are not changeable.

I do have the T-8 LED tube replacements. The T-8 replacements do not require any modifications according to their instructions. Unfortunately, these T-8 replacements require a working flourescent ballast an that is what had failed on the previous fixtures, so I could not use these.

Are your LED's dimmable?
They are not.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
In the US


These are direct 4 foot LED light fixtures. The "bulbs" are not changeable.

I do have the T-8 LED tube replacements. The T-8 replacements do not require any modifications according to their instructions. Unfortunately, these T-8 replacements require a working flourescent ballast an that is what had failed on the previous fixtures, so I could not use these.
As far as I'm aware there are basically two types of LED florescent replacements:

1: You apply voltage across either end of the tube, to do this you remove all the parts from the fitting, and simply apply mains to the ends of the tube. These are the types I bought.

2: The power goes in and out on one end, and then in and out on the other - to make it work you remove the starter, and replace it with a special 'starter' which is just a piece of wire inside shorting the pins together.

So type 1: you remove the ballast and starter etc. and wire direct to the tube. Type 2: you can leave the ballast in place, and simply replace the starter with the shorting link. However, the ballast isn't part of the tubes operation, and is only left there because it means you don't need to make any changes to the fitting. You could remove the ballast, and put a wire in it's place - it has no effect on the operation of an LED tube.

It sounds like the T-8 replacements you got were type 2?, so you simply fit the new 'starter' and short out the old faulty ballast.

Personally I'd recommend what I called 'type 1' above, and strip all the unwanted parts out of the fitting - but either type are fine.

I imagine what you've got are essentially dimmable, so aren't regulated against mains fluctuations, and your mains supply is dipping as the load from your washing machine machine varies.
 

Kart31

Member
As far as I'm aware there are basically two types of LED florescent replacements:

1: You apply voltage across either end of the tube, to do this you remove all the parts from the fitting, and simply apply mains to the ends of the tube. These are the types I bought.

2: The power goes in and out on one end, and then in and out on the other - to make it work you remove the starter, and replace it with a special 'starter' which is just a piece of wire inside shorting the pins together.
Type 3:
Remove T-8 floursecent light, install T-8 LED light. no modification necessary. (does require working ballast)

Type 4:
4 foot LED light fixture. Full fixture with LED lights installed. All in one units, no tubes or bulbs.
1607872058212.png

It sounds like the T-8 replacements you got were type 2?, so you simply fit the new 'starter' and short out the old faulty ballast.
I got neither your type 1 or 2. I got type 4 lights

I imagine what you've got are essentially dimmable, so aren't regulated against mains fluctuations, and your mains supply is dipping as the load from your washing machine machine varies.
I'm not sure what "essentially dimmable" is. These are not dimmable lights.
 

gophert

Well-Known Member
Most Helpful Member
1) check to make sure your washer is not drawing an excessive load - nearly seized bearings, for example, and causing a brownout in your house. Some 4-foot LED bulbs are especially sensitive to brownouts because they are a row of approximately 50 white LEDs and are only on for a small fraction of the power curve. If the peak voltage drops below 150v ac or the peak exceeds 150 for a very small amount of time (typically 168v peak), then it will appear to dim. 50 is just a number, yours may have fewer in series but the idea is the same.

option 2, do the lights dim on both phases in your house? Your neutral may be corroded or the transformer at the street may have a short that causes the center value of your split (120v) to be offset. Measure the outlet voltage in several rooms to make sure they are all 110 to 120 range RMS and close to the same. If you see some offset 105 vac in some rooms and 130 in others, you have a problem with neutral.
 

Kart31

Member
1) check to make sure your washer is not drawing an excessive load - nearly seized bearings, for example, and causing a brownout in your house. Some 4-foot LED bulbs are especially sensitive to brownouts because they are a row of approximately 50 white LEDs and are only on for a small fraction of the power curve. If the peak voltage drops below 150v ac or the peak exceeds 150 for a very small amount of time (typically 168v peak), then it will appear to dim. 50 is just a number, yours may have fewer in series but the idea is the same.

option 2, do the lights dim on both phases in your house? Your neutral may be corroded or the transformer at the street may have a short that causes the center value of your split (120v) to be offset. Measure the outlet voltage in several rooms to make sure they are all 110 to 120 range RMS and close to the same. If you see some offset 105 vac in some rooms and 130 in others, you have a problem with neutral.
As far as I know I can only measure RMS, as I believe that is what meters read. Both phases are steady at 118.1-118.2 and 118.2-118.3VAC both with and without the (brand new) washer running (measured in multiple locations). According to the clamp on ammeter and appropriate adapter cord (so I can connect only to the hot lead), the washer is drawing 11-12 amps, nameplate says 14.8 amps, on the NEC mandated single outlet 12 gauge wire-20 amp breaker circuit.

No lights anywhere in the house brown out at any time, other than during stormy weather when the power company is doing their line break checks. There flouresent lights on the same circuit and do not flicker.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Type 3:
Remove T-8 floursecent light, install T-8 LED light. no modification necessary. (does require working ballast)

Type 4:
4 foot LED light fixture. Full fixture with LED lights installed. All in one units, no tubes or bulbs.
View attachment 128490


I got neither your type 1 or 2. I got type 4 lights


I'm not sure what "essentially dimmable" is. These are not dimmable lights.
LED bulbs and tubes generally have regulated switch-mode supplies inside them, so don't vary in brightness if the incoming power fluctuates (within reason), because of this they aren't dimmable at all - and usually work just as well on 120V as 240V.

If the bulb/tube doesn't have a regulated switch-mode supply inside, then the brightness of the bulb/tube will vary depending on the supply voltage, hence 'essentially' dimmable - you wouldn't want to put your 120V tube of that type on 240V though :D A 'true' dimmable bulb/tube will allow variation over a considerably greater range though.

Your type 4 of course isn't a replacement T-8 tube :D
 

Nigel Goodwin

Super Moderator
Most Helpful Member
LED bulbs and tubes do not work on 120V as 240V. It needs more to be bright.
There are plenty of dual/multi voltage LED bulbs and tubes - for example:


Essentially, if it's regulated it can probably work on either. If it's NOT regulated, then no it can't.
 

Kart31

Member
I'm guessing this either got resolved or it was never a real problem anyhow.
You must not be a good guesser, as both are wrong.

Problem still exists, possibly you did not read the results in post 11, no further experiments proposed or items to check with the instruments I have, and the thread got side tracked talking about the various types of 4 foot LED lights.
 
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gophert

Well-Known Member
Most Helpful Member
When I said "guess", It should have been interpreted as, "I'm picking the scab off of this one to see if it bleeds". It still seems kind of raw but I'm not seeing blood and an open question has been answered.
 

Kart31

Member
When I said "guess", It should have been interpreted as, "I'm picking the scab off of this one to see if it bleeds". It still seems kind of raw but I'm not seeing blood and an open question has been answered.
At least you admit to it. That's a start. Perhaps your question has been answered but unfortunately not mine. I was going to let it die on the vine, but since you bumped it.

If anyone has any ideas on what I can check or experiments to perform, I'm all ears. Unfortunately I do not have a scope, so seeing noise or Vp-p is out (IIRC DMM displays Vrms). I am game to try a few things to get the LED lights to stop flickering.

Update: This is only the 4 foot lights. The LED bulbs in sockets (such as 1608159003641.png) do not appear to flicker.
 
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