Dooby test on a 10W LED floodlight

That's why they actually had to REMOVE the snubber networks from across the PIR relays. They kept the light on at a low level when off.

Big Clive

This is a great way of adding a half bright mode to an outside light. You could either bridge out the capacitor or bypass it with a two way switch. Not sure how up to code it would be, but ¯\_(ツ)_/¯

Matt Harrison

They should at least put a 2 year guarantee on such electrical items.

Andrew Donaldson

It's a pity that a 1uF variable capacitor would be humongous 😊 Thinking back to the old 500pF plate capacitors. 🤔

Zeedijk Mike

I agree, it would be great to see what happens if you could adjust the power to say 75% and 50% and what size cap is needed for that.

Adam Pepper

A resistor would work, but will consume energy. The "no loss" method is PWM: turn the 12V on and off quite fast (maybe 200Hz or more) and vary the duty cycle to control the effective voltage. A bit more complex - but fun if you're looking for a project.

Mike Page

at the risk of a daft question, would something similar work on 12v DC floodlights, or is the word I'm looking for " resistor " lol I have 2 x 30w 12vDC on the outside of my shed, would i just need a couple of decent resistors inline to reduce slightly and prolong the life

mark barratt

That's a very neat (I was going to say cool but someone has beaten me to it) hack. Hopefully when this video goes public it'll be popular beyond the usual sparkies/tinkerers circles. I can imagine this will be useful info for some of my ecomentalist friends too for example.

Jon Knight

Hey Clive! Have you seen Veritasium's recent video titled "This is why we can't have nice things"? He talks about how the longest running light bulb is ran at a lower wattage and stuff. It would be interesting if you did a video discussing stuff from his video.

Connor Strothman

A binary box (1 / 0.47 / 0.22 / etc) with safe shorting plugs would be ideal. Or switches (duh why did I say plugs?) And a DISCHARGE button to save blowing up your eBay LCR meter.

Mike Page

Clive, you need to make a 3D printed capacitor decade box type thing that we can safely test these things, good project, great vid.

Mike Wynne

Hmm. DIY doobie... Maybe an adaptor with inline capacitor(s) and two or more lamp sockets, so you can spread the load over multiple under-run bulbs...

Wim

Most drivers have a pair of parallel sense resistors somewhere in the circuit that allow nudging of the lights intensity and lifespan in your favour. The strip lights I use on the live streams are running at around half their design power.

Big Clive

Very cool test. Literally. :-) How would you go about creating an active switch for bench use that delayed the actual “off” until the zero crossing point of the current cycle? Would that have any utility beyond avoiding zappage?

Matt Hessinger

Blue to blue, green to green and brown via the capacitor or link.

Big Clive

Some strip lights have that feature built in.

Big Clive

I did something similar. I wanted to replace all my 8ft florescent shop lights with LED replacement 'tubes'. I wanted to see if the light output increased with the LEDs. I bought a cheap light meter from eBay just like you. I measured before and after in Lumens. Lumens are measured a specific distance from the light and should not have any other light influences. Because i just wanted an estimate i didn't make it too much trouble. It was a huge increase in light output. I would like to have added a capacitor for long life but i don't want to lose light output. Are there capacitor options to only lower the light output slightly but make them run a little cooler? I am in America running on 110v.

Matt Larson

An illuminating experiment.

Mike Page

I'm curious about that too!

Derek Smith

Would have been great to see the numbers at 2.2uf.

Derek Smith

Oh wow, I can finally reply to patreon posts!

Jeremy Impson

Any thoughts on how to measure such low current? Does the killawatt go that low?

Jeremy Impson

This makes a good hack for using a double light switch for multiple light levels, i.e. switch #1 toggles the light on/off and switch #2 bridges the capacitor to toggle between long life and full intensity. Assuming it's the same Pro Elec 10W 15 LED lamp on CPC and that light meter linearity is fine, this gives the following rough lumen calculations, starting with CPC's 700 lumen rating: Capacitor - Watts - Lumens - Lumens/Watt Link - 10.7 - 700 - 65 1uf - 3.8 - 340 - 89 470nf - 1.9 - 195 - 102 330nf - 1.5 - 149 - 99 220nf - 1 - 113 - 113 100nf - 0.5 - 49 - 98 47nf - 0.2 - 21 - 105 22nf - 0.1 - 7 - 70

Seán Byrne

A very satisfying test. You've really hit on something with these LED efficiency drives.

Ymir the Frost Giant

Lots of Lux, but where's the Daz and Omo?

Ymir the Frost Giant

it would have been interesting to try 2.2uF or 2 x 1uF in parallel. It should give little noticeable reduction in light and around 25% power saving.

So you're bridging the hot (brown) with the ground (green)?

One day we'll find it: The rainbow connector...

Michael Thompson

A nice project comes to mind...let’s use a pir to activate a relay wich bridges the capacitor...dim light at rest-state and a fully loaded one when someone passes by :)

Mike Weijmans

does it affect CRI at all ?

lImbus924