I thought LED lights were efficient? - Page 1
Forum section: electronics / general

author: Northy
author_rank: Regular Contributor
timestamp: April 02, 2022, 08:54:46 pm
content: Hi all,I was about to pull the trigger on some new batton lights for the garage, then I saw the energy rating on them and was shocked! I know they won't be really on very often or for very long, but I'm quite keen on things being efficient especially after energy prices have just gone up a lot in the UK.I was going to buy these, but they are out of stock:https://www.toolstation.com/v-tac-led-batten-cw-tubes/p33970Energy rating F (out of a possible A->G).Am I missing something here?As that one is out of stock, I started looking at others:https://www.toolstation.com/integral-led-lightspan-ip20-ik08-batten/p16505https://www.screwfix.com/p/lap-oxbo-single-4ft-led-batten-18w-2100lm-220-240v/465pp#BVQAWidgetIDhttps://www.amazon.co.uk/Ceiling-Surface-Mounted-Natural-Garage%EF%BC%8CWarehouse/dp/B0921N9L11/ref=sr_1_2?m=A2P55RBX0AFDJE&marketplaceID=A1F83G8C2ARO7P&qid=1648893162&s=merchant-items&sr=1-2Are these things just a load of SMD LEDs behind a plastic cover? If so does it really make much difference which one you buy as long as it's not so badly made that it's not safe?Does anyone have any recommendations for anything like these in the UK that they think are worth buying?Thanks,G

author: harerod
author_rank: Frequent Contributor
timestamp: April 02, 2022, 09:10:43 pm
content: <rant>We got new 24" monitors the other day, with an efficiency rating of "D" for a consumption of 14kWh/1000h. 14W average? Remember when a 17" tube slurped >100W?</rant>Thehttps://en.wikipedia.org/wiki/European_Union_energy_labelwas updated in 2021, with the goal of eliminating A++ ratings. The most parsimonious devices barely make it to "B".Since the label is based on law, for once we get free access to the actual texts (no obolus to (Aus-)Beuth-Verlag (German joke) required). The calculation scheme is given for each device.

author: eti
author_rank: Super Contributor
timestamp: April 02, 2022, 09:27:15 pm
content: They're VERY efficient... for the manufacturers, since every time the supposed "40,000hrs!!" rated life falls WAY short, you bin them and buy more.

author: BrokenYugo
author_rank: Super Contributor
timestamp: April 02, 2022, 09:32:42 pm
content: I mean, that first one is under 100 lumens/watt, miles more efficient than an old T12 florescent tube, but kind of crappy for a modern 80CRI (I assume) LED light.

author: tom66
author_rank: Super Contributor
timestamp: April 02, 2022, 10:28:55 pm
content: The energy rating scale changed a while back, so what was pretty much A+++ became 'C' or something like that. It's just to promote improvements beyond the previous maximum.One result was this odd disagreement between EU and post-Brexit UK ratings:-... Though I believe this was harmonised recently (not to get too political, but everyone knew that this would be the end result of Bx-it).

author: John B
author_rank: Frequent Contributor
timestamp: April 02, 2022, 10:48:05 pm
content: The problem will always be the driver circuitry. Low component count, low BOM cost and manufacturing cost are always top priority.I prefer to use commercial style 1200x300mm lights now as they are passive devices (ie you can supply them will power however you see fit, to whatever standard you wish), plus they have a large volume and surface area to power dissipation ratio, giving them a better ability to dissipate heat compared to compact LED retrofits, which will inevitably give them a better lifespan.The light quality has benefits too: you can get higher CRI panels, low glare etc...

author: james_s
author_rank: Super Contributor
timestamp: April 03, 2022, 12:38:20 am
content: The problem is that those consumer-oriented energy efficiency ratings are comparing to other similar products. LED lighting generally speaking IS efficient, but when you're comparing it to other LED lighting some of it is better than others. Personally I would ignore those ratings and look at the lumens per watt, a good baseline is conventional linear fluorescent lamps which are IIRC around 60 lm/W once you factor in ballast losses, or 50 lm/W for the compact lamps intended to replace incandescent. Those old incandescent lamps are only 10-15 lm/W.

author: themadhippy
author_rank: Super Contributor
timestamp: April 03, 2022, 01:09:41 am
content: Installed a load of v- tac led stuff about a year ago and not had any problems with it,the biggest hassle was some down lights,but the batons (https://cpc.farnell.com/v-tac/667-vt-8-40/grill-fitting-40w-led-120cm-6400k/dp/LA07398) impressed me enough to fork out for a couple.One 40w 4 ft baton made the old twin 4 ft florry look like a candle and the 10w 1 ft version makes a great light for the work bench

author: SiliconWizard
author_rank: Super Contributor
timestamp: April 03, 2022, 07:27:54 pm
content: Quote from: harerod on April 02, 2022, 09:10:43 pmYep. Bureaucracy at its best.

author: wraper
author_rank: Unknown
timestamp: April 03, 2022, 07:36:08 pm
content: Don't look on those efficiency ratings, calculate lumens per Watt (divide lumen rating by power consumption in W). Really good stuff has > 130lm/W. Half decent should have at least 100lm/W. Also as was already said, that efficiency scale got updated.

author: SiliconWizard
author_rank: Super Contributor
timestamp: April 03, 2022, 07:39:02 pm
content: Quote from: james_s on April 03, 2022, 12:38:20 amYes, the only metric to consider is how much power a given lamp draws for a given luminous power.Ultimately, in particular for "mundane" home lighting purposes, what matters is whether a given lamp gives you "adequate" lighting by your appreciation, and at what power from mains. Meaning that efficiency is only part of the question for your average use.If a given LED lamp is more efficient than another kind of lamp, yet draws the same power from mains, but outputs a lot higher luminous power (that you may not need), then it's more efficient, but you gain nothing. Just a thought.

author: AndyC_772
author_rank: Super Contributor
timestamp: April 03, 2022, 07:45:55 pm
content: If you're reading EEVblog, chances are you don't need to worry about arbitrary letter codes for efficiency - you'll understand the basic concepts of light output and wattage.I've just replaced all the old 58W fluorescent tubes in my garage with these:https://www.tlc-direct.co.uk/Products/LTT524HDL.htmlLess than half the power (24W vs 58W), and considerably brighter than the old tubes they replaced. I could probably have got away with only fitting one tube per fitting instead of the original two.

author: wraper
author_rank: Unknown
timestamp: April 03, 2022, 07:50:54 pm
content: Also with higher lm/W figure means you get more LED per lamp. For example I purchased Ikea Solhetta bulbs with 470lm luminous flux and only 3.4W power consumption while most of the similar bulbs have the same 470lm luminous flux but on average about 5.5W consumption. Took them apart and IKEA bulb had more than 3 times more LEDs inside. As running LED at lower current increases efficiency.

author: Siwastaja
author_rank: Super Contributor
timestamp: April 04, 2022, 10:50:31 am
content: EU energy labels are a complete joke, anyway. Just categorically ignore them, and for each type of gadget, learn enough to understand how actual energy efficiency needs to be calculated. There is no shortcut.Like wraper said, for illumination, the relevant figure is simply lm/W. Since both lm and W are reported for most types of lighting, it's easy to calculate.LED itself does not guarantee anything. Many many LED bulbs and fixtures on the market are around 90lm/W. While somewhat better than fluorescent, it's very crappy for LEDs by modern standards, this was maybe state-of-the-art in 2005. But this is what the cheapest stuff is - and sometimes, even expensive stuff is actually the cheapest crap in disguise!If efficiency matters to you, try to find at least 110-120lm/W LED bulbs, IMHO. This should not break your bank, unlike true state-of-the-art (>150lm/W).

author: tom66
author_rank: Super Contributor
timestamp: April 04, 2022, 11:13:04 am
content: Part of the reason so many LED bulbs have poor lm/W is because the LED chips run super hot, which shortens lifespan and reduces efficiency.

author: Ice-Tea
author_rank: Super Contributor
timestamp: April 04, 2022, 11:18:43 am
content: What pisses me off a bit is the whole "oh, all those fluorescents have got to go" as if it's written in the Bible.The really good fluorescents are at least on par with poor LED replacements.

author: Gyro
author_rank: Super Contributor
timestamp: April 04, 2022, 12:47:57 pm
content: I am still contemplating what LED replacement to use for the 8ft T12 125W florescent that I have in my garage. Centrally placed, the light it puts out is so bright and even that I'm loathed to retire it.I've added a PIR LED for trips to the freezer and washing machine, so the florescent only goes on when I'm actually working on something.

author: james_s
author_rank: Super Contributor
timestamp: April 04, 2022, 05:23:36 pm
content: Quote from: Gyro on April 04, 2022, 12:47:57 pmWhy not just keep using it? My house is almost all LED but I still have fluorescent in the laundry room and garage. It works and it's not particularly inefficient.,

author: Gyro
author_rank: Super Contributor
timestamp: April 04, 2022, 06:33:08 pm
content: Yes, that's pretty much the conclusion I've come to for the foreseeable future. I don't think they make 8ft tubes any more but I still have a spare, which should see me out. With an electronic starter, blackened ends seem to be a thing of the past anyway.

author: james_s
author_rank: Super Contributor
timestamp: April 04, 2022, 06:43:29 pm
content: Even if they don't make the tubes anymore you should be able to find one, now may be a good time to start looking for a spare. I collect lamps and have some fluorescent tubes from the 1940s so even old lamps turn up now and then.

author: SeanB
author_rank: Super Contributor
timestamp: April 05, 2022, 08:24:34 am
content: Still have a lot of 2ft and 4ft tubes, and installed one this week, because you do not get as much flicker from them compared to the LED, and the CRI on the Phillips Reflex tubes is really good. Still have a box of incandescent lamps though, with a good number being pre 1939 made.

author: SteveyG
author_rank: Unknown
timestamp: April 05, 2022, 11:04:22 am
content: Quote from: wraper on April 03, 2022, 07:36:08 pmLumens per Watt is a highly abused figure and rarely measured by a lamp manufacturer after integration. You are unlikely to get 100 lm/W in any retrofit style lamp after taking into account the temperature they run these things at and the power put through the LEDs.

author: wraper
author_rank: Unknown
timestamp: April 05, 2022, 12:48:27 pm
content: Quote from: SteveyG on April 05, 2022, 11:04:22 amEven if your claim was true, do you think it's better to use a bulb that has 100lm/l or 140lm/w in ideal conditions? Those numbers don't come from nowhere. Higher efficiency bulbs have way more LEDs inside them and a switch mode ballast, not just a linear or capacitive dropper.

author: f4eru
author_rank: Super Contributor
timestamp: April 05, 2022, 01:08:38 pm
content: Quote from: Ice-Tea on April 04, 2022, 11:18:43 amSo they are still worse in general.Quote from: Ice-Tea on April 04, 2022, 11:18:43 amOne huge factor to phase them out is the mercury content, and also it's bad habit to be inhaled when the tube is broken...

author: madires
author_rank: Super Contributor
timestamp: April 05, 2022, 01:34:29 pm
content: Quote from: Ice-Tea on April 04, 2022, 11:18:43 amIs anyone forcing you to change them? If you're happy with your fluorescents keep them running.I'm in the process of changing old style fluorescents with ballast and starter to LED. Most are converted to LED and some are replaced with new lamps for damp environments (the cover also provides some protection from mishaps). No specific brands, a mixed bag. So far the LED tubes are brighter, need less power and the instant-on is great too. I know, good electronic ballasts provide similar power-on times, but they aren't for free.

author: Ice-Tea
author_rank: Super Contributor
timestamp: April 05, 2022, 01:55:52 pm
content: Quote from: f4eru on April 05, 2022, 01:08:38 pmSure. My point is that it is not agivenand it is often presented as such. If you have a good fluorescent installation, not just any LED replacement will beat it and resources could be better spend elsewhere.Quote from: Ice-Tea on April 04, 2022, 11:18:43 amQuoteNo argument there.Quote from: madires on April 05, 2022, 01:34:29 pmNot at all. But agressive advertising makes it out as if you're an idiot if you're still runing fluorescent which is simply not always true.

author: themadhippy
author_rank: Super Contributor
timestamp: April 05, 2022, 02:23:42 pm
content: Here in the uk we've got until september 2023 before florrys get banned,existing stocks can still be sold,but once they've gone thats it.

author: james_s
author_rank: Super Contributor
timestamp: April 05, 2022, 03:37:31 pm
content: Quote from: themadhippy on April 05, 2022, 02:23:42 pmI hate bans. They should tax them based on efficiency if anything, there are still applications where fluorescent lamps are superior.

author: cdev
author_rank: Super Contributor
timestamp: April 05, 2022, 04:22:34 pm
content: I was having lots of problems especially with "feit" brand LED replacement bulbs widely sold at Costco, Home Depot, etc. But recently have been buying Phillips Warm White, and some cheapie MR-16 bulbs on ebay and they turned out to be very efficient (dont even get warm) very bright, a good color and generally GOOD.Since I have a bunch of the fixtures around, this is great for me. So now my wife and I are using (I think) 100% LED lighting.Despite the Feit fiasco which left me with a lot of defective Feit light bulbs which I would like to repair or remove the defective parts from and fix, or reuse the LEDS or something.Sometimes they half fail and cause RFI. Anybody have any good suggestions of how to effectively use all the white LEDs? (from LED bulbs that have burned out - either one or several LEDs have died rendering the bulb useless and dark unless the bad LEDs are replaced by means of hand soldering.

author: james_s
author_rank: Super Contributor
timestamp: April 05, 2022, 04:25:49 pm
content: I had changed out all of my compact fluorescent bulbs with LED by 2015. Philips and Cree have always been my favorites, I've had very few of them fail. The first LED bulbs I was buying were over $40 each but they still paid for themselves.

author: jmelson
author_rank: Super Contributor
timestamp: April 05, 2022, 04:34:57 pm
content: Quote from: Siwastaja on April 04, 2022, 10:50:31 amA few years ago I made up my own LED retrofit system. I used commercial LED power supplies with high efficiency, and got the best Cree LEDs available at the time (102 Lm/W) and mounted them on long strips of PC board material to act as a heat sink. These have worked quite well, with no detectable dimming since 2014. The power supplies draw ~21 W from the mains and deliver 20 W to the LEDs.Jon

author: Siwastaja
author_rank: Super Contributor
timestamp: April 05, 2022, 05:13:33 pm
content: Quote from: jmelson on April 05, 2022, 04:34:57 pmYeah, if you want state-of-art, you need to do it yourself. The exact same pattern can be seen in li-ion batteries (in battery-powered tools, powerbanks etc.) and LED illumination: cheap crap uses what was state-of-art 15 years ago; expensive brand products 10 years.Since the component (li-ion cell; or LEDs) manufacturers are producing and selling modern stuff all the time, the question is, where does it go? What explains the 10-15 year delay? Is it like production ramp-up taking 5 years (so you can't buy them in large enough volume at first), then product design cycle takes 2-3 years, and then the components sit in OEM warehouses for another 2-3 years before being assembled? I sincerely don't understand how it can be this long. It's a long enough time that hobbyists and small, agile startups have true, large advantage over the mass produced stuff anytime.

author: wraper
author_rank: Unknown
timestamp: April 05, 2022, 06:12:38 pm
content: QuoteI all goes down to economics. Why make better products and reduce your profit or encourage EU making restrictions on less efficient bulbs?https://www.mea.lighting.philips.com/consumer/dubai-lampFor example 1, 2 and 3 bulbs have 200 lm/w efficiency which you'll not find anywhere else other than in Arab Emirates.

author: Northy
author_rank: Regular Contributor
timestamp: April 05, 2022, 07:35:03 pm
content: Thanks for the comprehensive repliesIt's been an interesting read.I think I'll get a couple of the 40W V-TAC units and see how they go.Cheers,G

author: james_s
author_rank: Super Contributor
timestamp: April 05, 2022, 08:14:48 pm
content: Quote from: Siwastaja on April 05, 2022, 05:13:33 pmMy guess would be military, they get first dibs on all the latest cutting edge tech.

author: tooki
author_rank: Super Contributor
timestamp: April 06, 2022, 02:24:52 am
content: Do they, though?? Military and aerospace generally tend towards being technically conservative, sticking with older, field-proven components. Sure, there are someareaswhere they’re cutting-edge, but I think that on the whole they lean quite “old tech”.

author: Someone
author_rank: Super Contributor
timestamp: April 06, 2022, 03:21:19 am
content: Quote from: Siwastaja on April 05, 2022, 05:13:33 pmTry getting a volume order of the latest bleeding edge LED efficiency, its often easier to get small quantities of the edge bins while the process keeps improving, there is significant ramp up and even anticipated bins that never end up being produced in production volumes. But the LEDs that are available in volume? my guess would be going to the people who will pay the premium for the extra efficiency because of 24/7 or very high duty applications: retail lighting, airline interiors, TV studio lighting, etc

author: GLouie
author_rank: Regular Contributor
timestamp: April 06, 2022, 06:55:43 am
content: I recently took apart a failing Costco Feit 60W 90CRI LED bulb, and I think I will just be tossing the failed ones instead of trying to repair or scavenge.They are difficult to take apart. The entire base is a formed aluminum cone with a plastic overmold, then the plastic globe is silicone glued on and the threaded base dimpled on. I had to destroy the housings to get to the LED plate and circuit board, and I do not see a good way to disassemble and replace after a repair. The LEDs are reflow mounted, in this case 12 on a MCPCB disc arranged in 2 parallel banks of 6 in series. On mine, 1 LED had failed taking down a bank, so the whole lamp immediately had half output. The remaining 11 LEDS appear to at least work with a DMM diode test. I didn't research what LED these could be or the solder mount pattern, so couldn't say if these might be useful somewhere else. Soldering should be easy enough with a hot plate arrangement. Your Feits could be different.Probably further discussion of these should be in a new thread.Quote from: cdev on April 05, 2022, 04:22:34 pm

author: wraper
author_rank: Unknown
timestamp: April 06, 2022, 12:03:26 pm
content: Quote from: Northy on April 05, 2022, 07:35:03 pmMost of what V-TAC sells is below average. Of what you linked, V-TAC is the worst. Buying V-TAC is quite pointless unless you get them 2-3 cheaper than something decent.

author: themadhippy
author_rank: Super Contributor
timestamp: April 06, 2022, 12:19:40 pm
content: QuoteHave you actually installed any of there stuff? On a previous contract we used a lot of there stuff,the only minor issue was the ip rated down lights didnt come with instructions on the order of 2 silicon seals,however trial and error got it sorted.Over 12 months on and no call backs or failures and were not talking 1 or 2 fittings here,im talking about large retail spaces.

author: wraper
author_rank: Unknown
timestamp: April 06, 2022, 12:46:32 pm
content: Quote from: themadhippy on April 06, 2022, 12:19:40 pmI have a few V-TAC bulbs in my house. Purchased them only because because they were at sale for EUR 1 - 1.20 a piece for a 9-11W bulb. They are the least efficient of what I have and have a linear regulator inside them so I put there whey they are used only occasionally. V-TAC with at least 100 l/m is an unobtanium rarity (check their website). Even more expensive "Samsung LED" models have the same crap efficiency. They have a linear regulator and a very small number of LEDs inside for given power. Most of the half decent bulbs of such power have a switch-mode ballast inside them but not V-TAC.

author: Northy
author_rank: Regular Contributor
timestamp: April 06, 2022, 12:50:41 pm
content: These were the V-TAC battens that I was thinking of getting:https://cpc.farnell.com/v-tac/667-vt-8-40/grill-fitting-40w-led-120cm-6400k/dp/LA07398Do you really think the Integral LED ones:https://www.toolstation.com/integral-led-lightspan-ip20-ik08-batten/p16505Or LAP ones:https://www.screwfix.com/p/lap-oxbo-single-4ft-led-batten-18w-2100lm-220-240v/465pp#BVQAWidgetIDAre actually much better?I have one of the 4ft V-TAC retrofit tubes in an existing fixture already in the garage and have had no issues with it so far.G

author: wraper
author_rank: Unknown
timestamp: April 06, 2022, 12:54:20 pm
content: Quote from: Northy on April 06, 2022, 12:50:41 pmThis is surprisingly decent for V-TAC, 120 lm/w.QuoteAll of them have about the same efficiency, 116-120 lm/w

author: madires
author_rank: Super Contributor
timestamp: April 06, 2022, 12:56:08 pm
content: I have also some V-TAC LED bulbs and strips. No problems so far.

author: PushUp
author_rank: Regular Contributor
timestamp: April 06, 2022, 08:47:18 pm
content: This topic is too big, to give a comprehensive reply...but what is always true: "don't trust any label or imprint"!Just a short note, from what I have experienced so far:1. OSRAM (2700K / 8.5W / 68mA)My experience:- OSRAM does not last very long, but you can repair them easily- the power factor is very bad: 0.59 PF2. NEDIS (2700K / 11W / 70mA)My experience:- I am quite happy with this brand- the power factor is not that bad: 0.89 PF3. OSRAM filament Cool White (4000K / 11W / 52mA)My experience:- filament means = beyond repair (at least for me!)- as it is "cool white" the power factor is very good: 0.95 PF(the best power factor for LEDs I have seen so far)- in contrast to "cool daylight filament": 0.61 PF (6500K / 10W)- and in contrast to "warm white filament": 0.59 PF (2700K / 11W)...i will probably check some more led fluorescent lamps in the future...Here my two G13 (120cm) LED fluorescent lamps as a comparison: a cheap one from "Müller Licht" with 0.54 PF and a more expensive one from Osram with 0.92 PF. When I am not mistaken the Osram was the same price as the complete LED fluorescent lamp from "Müller Licht" in an IP65 housing with 2 x G13, 120cm; of course not the best build quality, but you get what you pay for... ;-)Müller Licht G13, 120cm (4000K / 18W / 151mA)with the worst power factor for LEDs I have ever seen: 0.54 PF...and here the whole lamp with 2 x G13, this time with a power factor of: 0.58 PF for both LED fluorescent lamps in the IP65 housing:OSRAM LED SubstiTUBE STAR ST8S, 120cm (6500K / 16.4W / "no info" mA)with the 2nd best power factor for LEDs I have seen so far: 0.92 PFCheers!

author: cdev
author_rank: Super Contributor
timestamp: April 08, 2022, 12:41:36 pm
content: If you are concerned about rising levels of mercury in the air, especially if you live in an area where its a serious problem for any one of many reasons, (Use of certain kinds of coal, or tilling of land may be two) you should invest in a bunch of NAC, and take it daily, whenever you remember to. Not only will this improve health generally by raising glutathione, but it will also allow your body to rapidly remove Hg from your body via theglutathioneroute.It will also make you more resistant to a great many diseases. Your body needsglutathionemore and more as you age and NAC is the best way I know of to ensure you get enough of it.You cant ingest it orally, its made from cysteine, glutamine and glycine in your diet, cysteine being the rate limiting one.https://pubmed.ncbi.nlm.nih.gov/?term=n-acetyl-cysteinehttps://pubmed.ncbi.nlm.nih.gov/?term=glutathione...since youre concerned about elemental Hg in the atmosphere, you're clearly concerned about glutathione as thats (depleting glutathione in our bodies) elemental Hg's main adverse effect, from what I know.You can read more at nutrition.org for free.As we get older we need more and more cysteine in our diets. (whey and dairy products being the most abundanbt dietary source besides n-acetyl-cysteine. I usually buy a kilo of it at a time and ensapsulate it in big OOO caps because its handy to have around. One effect of doing this is hearing loss prevention. Lots of little things like that.

author: Psi
author_rank: Super Contributor
timestamp: April 08, 2022, 01:02:29 pm
content: I Highly recommend you only ever buy LED lights that you can control their output power on. Then run them at lower than rated power.Either using a dimmer, variable power supply or whatever.Set them up so they run under 60degC. If you can't touch them with your finger then they are running too hot.A lot of the LED lights you by run at 85degC. They are engineered to fail.This is why I love LED strip. It spreads the heat dissipation from ~100 leds over many meters of strip instead of in one big ball.And if the psu fails you can replace the psu without replacing the leds themselves.

author: madires
author_rank: Super Contributor
timestamp: April 08, 2022, 01:33:40 pm
content: Quote from: Psi on April 08, 2022, 01:02:29 pmAnd they are great for creative lighting. Got a broken LED tube? Remove the PCB strip, stick a 12V LED strip on the aluminium and you'll have a nice workbench light which will last for a long time.

author: Siwastaja
author_rank: Super Contributor
timestamp: April 08, 2022, 02:06:41 pm
content: Quote from: cdev on April 08, 2022, 12:41:36 pmWhile NAC is pretty benign and likely won't cause ill effects (and has some legitimate uses and positive effects), it's weird how you recommend this not based onfactualmercury levels in the air, but based onconcernsthereof. By what mechanism does the NAC sense the concerns and help with them?For yourconcerns, I'd recommend homeopathic products. They are less likely to do any harm than actual nutritional supplements (or medication).

author: mazurov
author_rank: Frequent Contributor
timestamp: April 08, 2022, 06:56:22 pm
content: Quote from: Psi on April 08, 2022, 01:02:29 pmAlso, the supply in some of LED lights is not potted so you can derate the light itself.

author: james_s
author_rank: Super Contributor
timestamp: April 08, 2022, 07:51:33 pm
content: If you buy quality bulbs they are pretty reliable. I have lots of LED bulbs that are >10 years old, the one in the porch light by my front door was installed in 2011, runs dusk till dawn and still looks like new. I have a bunch of Philips Hue bulbs too, both white and RGB varieties and I've yet to have one of those fail.

author: Northy
author_rank: Regular Contributor
timestamp: April 08, 2022, 08:42:47 pm
content: I've ordered a couple of the V-Tak 40W LED battens today, when they come I'll see if they'll open up easily to see how they are driven. I've seen Big Clive on YouTube turning down LED bulbs to greatly improve their life.Thanks,G

author: cdev
author_rank: Super Contributor
timestamp: April 09, 2022, 12:37:10 am
content: Quote from: james_s on April 08, 2022, 07:51:33 pmHow do they do in cold weather. When its cold, it seems some LED lamps struggle to stay lit. CFLS are even worse.I've never read about this.

author: james_s
author_rank: Super Contributor
timestamp: April 09, 2022, 09:49:06 pm
content: Quote from: cdev on April 09, 2022, 12:37:10 amLEDs love the cold, I've never heard of one having trouble in cold weather. Certainly none of mine have ever caused me problems, the coldest I've ever seen it get here since installing the LEDs was about 12F and they were perfectly fine in that.

author: PushUp
author_rank: Regular Contributor
timestamp: April 09, 2022, 10:17:12 pm
content: Just as an add-on to a message I wrote - this is my main equipment, together with a small saw not in the picture:As for checking/repairing a dead SMD LED, you immediately spot the black dot:My HMC8012 and Gossen Metrawatt do use > 6V in diode mode, so that I am able to test each SMD LED. Of course I don't see the voltage drop, but the DMM is able to light up any SMD LED, which neither my Fluke 289, nor my Keysight U1273A is able to do so.If you wanna have it a bit easier, you may wanna invest in a ZEN50 from Atlas Peak, which shows the voltage drop of around 7.2V at 2mA or a little bit more at 10mA and so on.You can shorten this procedure with the ZEN50, when only testing the (most likely) one dead SMD LED and all other start flickering immediately, so that you know, that you are on the right track!That's it. Cheers!

author: Siwastaja
author_rank: Super Contributor
timestamp: April 10, 2022, 07:50:52 am
content: Any even remotely decently designed LED bulb works at however low temperature just fine.Misdesigned crap can fail to work due to any "external" reason. The real reason is failure in engineering, deliberate or not. In other words, there is no actual real engineering reason why LED lights should fail to operate at low temperatures. Fluorescent lamps are different, they really need to maintain high temperature inside the tube, as evidenced by the warm-up times even in room temperatures. LEDs work only better, the lower the temperature. Increasing ESR of electrolytic capacitors at low temperatures is the only "problem" I can think of, but it should not be a show-stopper. Cheap crap often even does not use them (evidenced by flicker).Some manufacturers take advantage of the reputation of crap products failing at low temperatures, selling "special" low temperature LED bulbs. I would not buy them, and just try to find normal products with decent reputation, and if they fail to work as they should, return to seller and claim for money back.

author: madires
author_rank: Super Contributor
timestamp: April 10, 2022, 10:30:58 am
content: Quote from: cdev on April 09, 2022, 12:37:10 amLEDs in the garage work just fine. Even in the fridge.

author: BrokenYugo
author_rank: Super Contributor
timestamp: April 10, 2022, 06:56:13 pm
content: Quote from: cdev on April 09, 2022, 12:37:10 amI would assume cracked solder joints or something to that effect. LEDs can handle a lot more than earthly cold and the driver parts are all good for it, if you go on youtube you can find demonstrations where they dunk a regular non phosphor 5mm LED into a small container of LN2, which is cold enough it screws with the semiconductor physics and changes the color of the output dramatically.

author: cdev
author_rank: Super Contributor
timestamp: April 12, 2022, 03:18:47 pm
content: Thanks for that pointer. This is very interesting to see and know.his is an RF-excited lamp..Look at the related videos for more..

author: Northy
author_rank: Regular Contributor
timestamp: April 13, 2022, 05:28:42 pm
content: The lights were delivered and they are the wrong brandGraham

author: wraper
author_rank: Unknown
timestamp: April 13, 2022, 05:36:44 pm
content: What did you actually receive? Not necessarily they are any worse.

author: Northy
author_rank: Regular Contributor
timestamp: April 14, 2022, 09:55:45 am
content: They have sent LEDBRITE units, not the V-Tac ones.On the specs (which I know can be massaged) these ones are 100W/lm and the V-Tac are 120W/lm.I think I'd rather have the V-Tac just due to them being a 'bigger' brand.G

author: Northy
author_rank: Regular Contributor
timestamp: May 26, 2022, 09:16:29 pm
content: A little update. I finally got them sent back and a refund.I've just ordered two more of the V-Tacs, lets see what turns up next weekG

author: TimFox
author_rank: Super Contributor
timestamp: May 26, 2022, 09:42:20 pm
content: I assume you mean lm/W, not W/lm.

author: DavidAlfa
author_rank: Super Contributor
timestamp: May 26, 2022, 11:10:33 pm
content: Then there's this, with Z+++ energy rating and 100W per lumen

author: TimFox
author_rank: Super Contributor
timestamp: May 26, 2022, 11:11:34 pm
content: I never watch the videos. How many lm/W can be extracted from the arc?

author: BrokenYugo
author_rank: Super Contributor
timestamp: May 26, 2022, 11:57:08 pm
content: A quick google indicates something like 4 to 9 lumens/watt for carbon arc.

author: Zero999
author_rank: Super Contributor
timestamp: May 27, 2022, 08:39:39 am
content: Quote from: james_s on April 09, 2022, 09:49:06 pmIf that's the coldest it's been in 10 years, that's pretty mild compared to most of North America and much of Europe. Presumably you live on the west or south coast. It did get down to -12°C back in December 2010 where I live in central England, which is very rare, where the normal coldest night is -6°C. I didn't have an LEDs outdoors back then, but my parent's had some CFLs outside and they carried on working, although I believe they were the bi-pin type with the internal starter and external magnetic ballast.I don't think it's the LEDs themselves which have a problem with the cold, but the electrolytic smoothing capacitor, which can increase in ESR at low temperatures. It would be interesting to hear someone's experience who lives in a colder climate.

author: wraper
author_rank: Unknown
timestamp: May 27, 2022, 09:10:41 am
content: Quote from: Zero999 on May 27, 2022, 08:39:39 amESR increases but not that much to break operation of something which is not broken by design and is not marginally operational at room temperature (unless cooled to extremely low temperatures).

author: Zero999
author_rank: Super Contributor
timestamp: May 27, 2022, 09:46:24 am
content: Quote from: wraper on May 27, 2022, 09:10:41 amIt wouldn't surprise me if a good number of LED lamps are prone to malfunction, or even failure at very low temperatures. The ESR of an aluminum capacitor roughly doubles, every time the temperature is reduced by 15°C. If the person designing the circuit chooses a part specified at 25°C, the ESR will increase by an order of magnitude at -30°C. The capacitance also drops off a bit and lower temperatures, which doesn't help.https://www.avnet.com/wps/portal/abacus/resources/article/understanding-esr-in-electrolytic-capacitors/https://www.researchgate.net/figure/ESR-versus-ambient-temperature-for-sound-capacitors-measured-at-66-kHz_fig1_29640251https://www.dfrsolutions.com/hubfs/Resources/services/Uprating-of-Electrolytic-Capacitors.pdfhttps://www.rs-online.com/designspark/suffering-from-esr-fluctuations-due-to-temperature-maybe-its-time-to-polymerise

author: wraper
author_rank: Unknown
timestamp: May 27, 2022, 10:25:57 am
content: It will increase voltage ripple but not so much that lamp should stop working.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: May 27, 2022, 10:31:40 am
content: Efficiency is good, but often isn't a sensible metric to drive replacement. I have outbuildings used primarily for storage. The lights are operated only a few hours a year. Damage to the environment from the manufacture and installation of high efficiency units would exceed the savings in operation. While LED lights would be better light, turn on faster etc. it just doesn't make sense to change them. A shop used only some evenings and weekends is a less extreme case but may have the same answer.

author: Siwastaja
author_rank: Super Contributor
timestamp: May 27, 2022, 02:42:07 pm
content: Quote from: wraper on May 27, 2022, 09:10:41 amYes and the increased ESR causes increased power dissipation in the capacitor, heating it up, causing the ESR to drop againIn even remotely acceptable design, one could expect a tad more flicker in cold weather, especially for the first few minutes after turning on. But of course, everything is possible, you can fail designs in very peculiar ways, even if physics is on your side.

author: Northy
author_rank: Regular Contributor
timestamp: May 31, 2022, 08:18:16 pm
content: New lights are here, very flimsy, I think the knock offs I sent back might have been better builtOh well, never mind. I'm tempted to open them up and look at how they are driven. See if the LEDs are being grilled!G

author: Northy
author_rank: Regular Contributor
timestamp: May 31, 2022, 08:40:42 pm
content: OK, I popped the ends off quickly.......There is a driver PCB in each end of the light (although the mains wire only goes into one end). The PCBs look well made to me, but it’s also interesting that they don’t fit in the housing as it looks like they originally designed to do (there’s some small features in the plastic that are there to kind of hold a board) as they are smaller than the features and held in with that white snot glue stuff.The main ‘body’ of the light is plastic, no aluminium to be seen - this also gives me hope they are not overdriving the LEDs and just producing heat? Maybe they have figured out that using more LEDs and no aluminium (as heat sinking) is the cheapest way to produce them.Anyway, I'll fit them at the weekend and see how they go.G

author: Northy
author_rank: Regular Contributor
timestamp: June 06, 2022, 04:31:29 pm
content: Lights fitted, very happy with them so far for anyone interestedG