Flashing PIR LED floodlight

[Canardly]

My 50w LED floodlight has just started flashing repeatedly when operating. Should I consider it doomed and therefore requiring replacement? The wiring and junction box looks sound and the fitment is water free.

[Diver300]

My 50w LED floodlight has just started flashing repeatedly when operating. Should I consider it doomed and therefore requiring replacement? The wiring and junction box looks sound and the fitment is water free.

It needs to be replaced.  A nerd who does electrical repairs I could have a go at repairing it but it's not worth the time and effort when postage two ways is needed.

The problem is that the LEDs and other components are driven near their limits and run very hot, leading to short lives.

There are lots of designs of LED drivers. I have fixed one type of lamp by running it via a bridge rectifier and having a 400 V electrolytic to smooth the DC. That type has their own rectifier and capacitor inside, but the capacitor is too small and runs too hot so does not last. Having one outside allows it to be larger and run cooler. However, many lamps won't run on DC or will misbehave in some other way, and it's not easy to know how the circuit works without opening one up.

[Kim]

Yep, textbook failure mode.  Some of the LEDs cook and fail short circuit, triggering the driver's overload protection, so it shuts down.  It then restarts a fraction of a second later, lighting the remaining LEDs, overloads again and repeat.  The world would be a better place if the drivers could detect this happening and stay off until power-cycled, and even better than that if the designs weren't penny-pinched with regard to heat dissipation.

A big part of the problem is that it's hard to non-destructively evaluate whether a given LED fixture is any good.

[Canardly]

Thx both.

[rogerzilla]

I saw my first new-fangled LED streetlight doing this the other night.  The streets will be like discos soon.

[nmcgann]

The problem is that all the cheap rubbish products have driven the slightly more expensive and better ones out of the market. I had the same problem with a pir led fixture lighting the path to my shed in my last house. All the cheap fixtures serially failed just past the warranty expiration date with either the leds dying or the pir filling up with water.

My last attempt was spending twice the amount to get a product with a 5 year warranty and buying via CPC so I would have a decent chance of returning it and getting a replacement. I moved house a couple of years after installing it so I don’t know if my plan worked, but it had already lasted twice as long as most of the others.

[Kim]

I saw my first new-fangled LED streetlight doing this the other night.  The streets will be like discos soon.

Last year (I haven't been that way recently) most of the streetlights on the A38 between Rubery and the M4 were winking on and off every couple of seconds.  It was basically a disco.

[Kim]

The problem is that all the cheap rubbish products have driven the slightly more expensive and better ones out of the market.

Not just that, but unless you have some electronics knowledge and are prepared to destructively disassemble glued enclosures, it's hard to tell whether an expensive lamp is actually better, or just more expensive.

[Diver300]

The problem is that all the cheap rubbish products have driven the slightly more expensive and better ones out of the market.

Not just that, but unless you have some electronics knowledge and are prepared to destructively disassemble glued enclosures, it's hard to tell whether an expensive lamp is actually better, or just more expensive.

It's also very difficult to find if a lamp flickers* until you power it up, which isn't usually possible without buying it.

*No sir, that's not flickering, it's modulation. 100 Hz** is too fast for humans to see.

**I've noticed that a car tail light was operating at 2000 Hz.

[Kim]

The problem is that all the cheap rubbish products have driven the slightly more expensive and better ones out of the market.

Not just that, but unless you have some electronics knowledge and are prepared to destructively disassemble glued enclosures, it's hard to tell whether an expensive lamp is actually better, or just more expensive.

It's also very difficult to find if a lamp flickers* until you power it up, which isn't usually possible without buying it.

I confused the landlord's electricians by asking if I could power up the bathroom light fitting they were planning to install on the bench before they started drilling holes in things.  Fortunately it was rock solid DC.  Would have become awkward if it wasn't.

[rogerzilla]

In t'olden days, better shops tested light bulbs before selling them to you.

[Kim]

Sort of place that would have a Cliff Quicktest behind the counter, no doubt.  (To be fair, those were a lot more common in the days before appliances were sold with plugs.)

[aidan.f]

Kim, you never cease to  amaze me with 'stuff' . I had to look that reference up, last time I used one was about 1990
s'pose you have one? 

The Quicktest is ideal for electrical shops, factories, labs and service departments.
compact, robust, power connector designed for temporary, safe and efficient connection of unterminated cables to 250V AC
With its lid open the wires of a plugless lead can be inserted into the insulated clips. When the lid is closed, current passes to the equipment.

https://www.cliffuk.co.uk/products/tools/quicktest.htm

[Kim]

It makes irregular appearances on Big Clive's Youtube channel.  When he isn't stuffing wires into the speaker terminals on his dubious Hopi power meter.  Which is how I know what it's called.  I don't think I've seen one in the flesh since the early 90s.

(I rarely need to do mains-voltage lash-ups, so I have a power lead terminated in a knockoff of a 3-terminal inline connector that Wago haven't yet got round to making, which is the cheapskate remember-to-turn-the-power-off-first version.)

[Canardly]

Have purchased an Ansell replacement and sparks is coming monday. We will see. A concern is that I can't turn the damn thing off. (no there is no dimmer switch).

[Feanor]

Kim, you never cease to  amaze me with 'stuff' . I had to look that reference up, last time I used one was about 1990
s'pose you have one? 

The Quicktest is ideal for electrical shops, factories, labs and service departments.
compact, robust, power connector designed for temporary, safe and efficient connection of unterminated cables to 250V AC
With its lid open the wires of a plugless lead can be inserted into the insulated clips. When the lid is closed, current passes to the equipment.

https://www.cliffuk.co.uk/products/tools/quicktest.htm

I've always known those as a 'Safebloc', from the discontinued RS product of the same name.

They were in widespread use in all electronics maintenance labs I worked in, prior to the era of moulded plugs.
People would remove their plugs from TVs etc before bringing them in for repair, in the belief that we would steal their plugs otherwise.

On one occasion, I was manhandling an amplifier chassis back into its wooden cabinet, when something fell off a shelf and slammed it closed, delivering a nasty jolt to me!