Test Equipment Anonymous

My brother recently pointed me in the direction of https://www.amazon.co.uk/gp/aw/d/B0FC5Z8GFQ "Relybo Torches Led Super Bright Rechargeable 1000000 Lumen Long Lasting 40H". At £8 including P&P, it was a "stupid price", i.e. stupid to spend more than 1s making a decision.

So, what's it do? The main point of interest is a single very bright white LED with an excellent focussing lens in front of it, and the power can be varied over a wide range. It also has flashing and SOS modes, plus a string of "tungsten" LEDS, but they are uninteresting.

When completely defocussed it projects a uniform circle, with a half angle of ~45 degrees. It is visible on trees ~100m away.
When tightly focussed the circle is less uniform, with a half angle of ~10 degrees. It is visible on concrete 5m away in broad daylight, and on trees ~500m away at night, but I'd have to make a special journey somewhere to test that properly. Just a bit brighter than the incandescent bulb and ZnC cells from my youth!

The current through can be varied from 2.2A to 0.09A, a 24:1 ratio.
It is supplied with a "5000mAh" 26650 cell.
If we believe that capacity, then the claimed 40H lifetime is not implausible at minimum brightness.

So how bright is it? Time for a trivial homebrew brightness meter...

A (45yo) square photodiode 2.5mm on a side was connected as a reverse biassed PIN diode, so the current is a linear function of the applied power, with 1mW optical power producing 0.5mA current. Hence from the current and the area, the incident power can be determined.

Fully focussed, the max brightness photodiode current was 3mA initially, falling to 2.5mA over the course of a minute and to 2mA after a few minutes. I guess there was a heating effect somewhere in there. The min brightness photodiode current was 0.15mA. That's somewhere around 15:1 or 20:1, which indicates the efficiency is falling off slightly at high powers; no surprises there.

The 3mA/6.25mm² corresponds to 950W/m², with 2mA corresponding to 640W/m². As a rule of thumb, the sun's maximum irradiance is around 1000W/m², so the torch is as bright as full sunlight.

Given that people are warned not to look directly at the sun (I did as a kid, of course), and that there have been "have you damaged your eyes looking at the solar eclipse" articles, I think it is reasonable to regard the torch as dangerously bright. Given the possibility of specular reflections when not in the great outdoors, I will be using a strip of 1cm wide insulation tape to hold the lens in the defocussed position. Easy to remove if I ever want a focussed beam.

So it definitely could be used as an offensive weapon to dazzle an assailant at night, and possibly to damage their eyesight permanently. It could also be used as a cosh[1]. Overall the torch is both a useful household item and an offensive weapon.

[1] UK background: if you keep a baseball bat by your bed and clobber and kill a nighttime burglar, then you could be convicted of murder with an offensive weapon. If, however, you use a large household torch that just happens to be nearby, then you will get off because you picked up the nearest object to defend yourself.

A QI car headlamp produces around 1500 lumens. A "pocket rocket" souped up flashlight using a single Cree LED, something over 2,000 lumens. They get very hot. A decent production single LED flashlight, around 1200 lumens. Claims of 1,000,000 lumens should be treated with the utmost scepticism. I just looked on the Candle Power Forum and could find no mention of this remarkable product.

I have a couple of old welding masks with grade 9 filters which were fine for looking at the eclipse. You can have one to avoid eye damage when using this 1 Mega lumen torch.

To me it looks like just another OK cheap LED torch with a very creative sales pitch. Things like this used to be sold as frighteningly bright, normally only sold to special forices, with a strobe mode that would brain freeze attackers. "Wait a second Mr Burglar while I select strobe mode on my torch to brain freeze you".
https://www.ebay.co.uk/itm/317686133287?

If you want something intended to deal with burglars, there's this, among others.

https://www.thehomesecuritysuperstore.c ... n-baton-9m

"blind them with the strobe, keep distance with 14.6 inches of reach, or deliver 9 million volts on contact". It doesn't mention the obvious of stoving in their skull with a single blow.

https://www.ebay.co.uk/itm/306358109748?

has a picture showing the correct method of application.

Or you could go low tech and old school and get a 6 cell or 4 cell Maglite, which has been used by policemen to subdue troublesome suspects for decades.

https://www.amazon.co.uk/Mag-Lite-D-Cel ... B0168UNMJG

They really have some heft. You are more likely to be able to argue it was just a domestic object lying by the bed, which came to hand in the dark, than for a truncheon like thing, quite like a baseball bat, and capable of delivering a hefty shock.

Have fun with it. I shan't be placing an order as I have half a dozen LED torches, mainly Convoy, which are very useful.

I used to keep a six D cell Maglite by the bed, but the batteries failed, swelled, and couldn't be got out...

When it comes to lies, its seems torches are even more creative than 1970s amplifiers with their music power, peak power, and Sinclair watts. But I have to admit that my little 3W LED torches powered by a single 18650 lithium cell are way brighter than the big Maglite and you definitely don't want to accidentally look straight into them. But they wouldn't be any good for subduing a burglar.

I don't understand the vast variety of light-based units. Even Horowitz and Hill mention the multiplicity of similar units is "baffling". Fortunately professionally I've been able to stick to watts.

1970s amps also used to avoid attention given to "transient intermodulation distortion", which the mags regarded as an advanced and mysterious topic. If only they had thought of looking at the slew rate with a square wave input, everything would have been much simpler.

As for specific numbers, yes big numbers are suspicious. I include the 40hours in that, so was mildly surprised to see it wasn't impossible.

I have a couple of welding filters left over from the 1999 total eclipse - which i actually say through a gap in the clouds! Not sure where they are, but I did find some mylar film cardboard specs which I use to look at the recent partial eclipse.

I suspect the 9MV would be classed as offensive weapon, not something lying around!

My ex used the 6 cell maglite to help he reel a little safer at night.

Overall, the cheap torch cost less than a hummus+sourdough snack in my local cafe. Not worth thinking about! Helena wants the one you gave me

But it was interesting to compare the brightness to full sunlight.

The torch I usually use is an Eagle Eye XR2. It's a cylinder about 23mm in diameter and 12cm long. It's nicely made with proper anodising, a Cree LED, and square cut anodised coarse threads. ebay cheapies have fine threads which are prone to wear out and be cross threaded, they also usually have cheap LEDs which are very blue. The Eagle Eye could be ordered with a choice of colour temperature for the LED. It throws a wide beam which is fixed. It is USB chargeable and the internal charger appears to be accurate as to final voltage. That and a Panasonic 3200mAh 18650 Li-ion cell cost about £15 from Aliexpress 10 years back. Unfortunately they are no longer made, but i am sure there are similar products. It has low, medium and high modes. No irritating SOS and strobe. I bought a couple more as gifts, which were well received.

On low it produces about 40 lumens (much better than an old style 2 D cell torch) and is claimed to last around 35 hours. On medium it produces 200 lumens and is reckoned to last 5 or 6 hours. On high it produces 600 lumens and is claimed to last 100 minutes. Low is bright enough for most indoor use and you can see your way outdoors. Medium is plenty for most outdoor use. I don't use high that much. It's much better than messing with candles when there are power cuts. I put it on medium and stand it on its end.

I have several others.

i am sure the Relybo torch will be useful and well worth £8. I don't much like the exaggerated, and I'd say deceptive, presentation on Amazon.

Very low brightness is sufficient for a surprising number of purposes. Candlelight was sufficient for exam revision when I was a kid I do still have a large lump of paraffin wax somewhere, "just in case".

I regard any description on Amazon as being deceptive, and use it as little as possible - twice this year. Reasons: I don't like the +30% "amazon tax", the way they treat their (non)employees, and the appalling search function.

The exception is where the item is from a reputable manufacturer, has been recommended (e.g. by Which?), and isn't available elsewhere for a similar price. One example was my Samsung tablet.

EC8010 wrote: ↑Wed Sep 02, 2026 9:50 am I used to keep a six D cell Maglite by the bed, but the batteries failed, swelled, and couldn't be got out...

When it comes to lies, its seems torches are even more creative than 1970s amplifiers with their music power, peak power, and Sinclair watts. But I have to admit that my little 3W LED torches powered by a single 18650 lithium cell are way brighter than the big Maglite and you definitely don't want to accidentally look straight into them. But they wouldn't be any good for subduing a burglar.

I have to agree with you. I have one of those as well, and it even has a HOT warning printed near to the lens, but in practice I have never actually felt it getting anywhere near to being uncomfortable to hold in your hand.

Zenith wrote: ↑Wed Sep 02, 2026 11:32 am The torch I usually use is an Eagle Eye XR2. It's a cylinder about 23mm in diameter and 12cm long. It's nicely made with proper anodising, a Cree LED, and square cut anodised coarse threads. ebay cheapies have fine threads which are prone to wear out and be cross threaded, they also usually have cheap LEDs which are very blue. The Eagle Eye could be ordered with a choice of colour temperature for the LED. It throws a wide beam which is fixed. It is USB chargeable and the internal charger appears to be accurate as to final voltage. That and a Panasonic 3200mAh 18650 Li-ion cell cost about £15 from Aliexpress 10 years back. Unfortunately they are no longer made, but i am sure there are similar products. It has low, medium and high modes. No irritating SOS and strobe. I bought a couple more as gifts, which were well received.

On low it produces about 40 lumens (much better than an old style 2 D cell torch) and is claimed to last around 35 hours. On medium it produces 200 lumens and is reckoned to last 5 or 6 hours. On high it produces 600 lumens and is claimed to last 100 minutes. Low is bright enough for most indoor use and you can see your way outdoors. Medium is plenty for most outdoor use. I don't use high that much. It's much better than messing with candles when there are power cuts. I put it on medium and stand it on its end.

I have several others.

i am sure the Relybo torch will be useful and well worth £8. I don't much like the exaggerated, and I'd say deceptive, presentation on Amazon.

Well, we'll find out just how good it is in a couple of days, I've just purchased a couple and they should be with me on Thursday. I don't expect the power to be anywhere near what they claim, but it will kick any regular battery-powered torch's butt from here to hell and back.

Yes, it will kick butt - and retina.

As I say, to reduce the chance of accidental indoor specular reflections, I loosely tape my torch in the wide angle position

That Eagle Eye XR2 looks very similar to my newer torches, just changed in cosmetic details. I hope the electronics are better than mine because out of the four I bought, one's electronics failed perhaps a year later and another's battery failed. My two older torches call themselves TrustFire TR-801 and although they don't have a USB charger, they also don't have the irritating flickering mode and are now about eight years old (maybe older) with no problems.

The Eagle Eye XR2 has had a lot of use over the past 8 or ten years since I bought it, and is still going strong. So have the ones I gave away. The other one I have like that is a Convoy S2. It has no USB charger but does have the disco modes, which it can be set to avoid. Convoy and a few other Chinese makers produce quality goods, arguably as good as premium brands such as Olight, but much cheaper. They are definitely a cut above the bargain offers, with sensational descriptions, on ebay.

https://convoylight.com/collections/new-products

They are not that much dearer than the cheapies. They also sell spare parts, which is reassuring.

It pays to buy quality Li-ion cells; Panasonic, LG or Samsung, if possible. When ebay sold 18650 cells there were numerous offerings with totally OTT claims made for them. 9900mAh for instance. They were usually recovered from dead laptop packs and re-skinned. You'd be lucky if they had more than 600mAh capacity. I don't believe top tier makers ever produced an 18650 with more than 3600mAh capacity.

Attention seems to have moved away from 18650 cells and towards 21700 cells. They are not that much bigger but have extra useful volume, and so significantly greater capacity.

Surefire is a well-established western company selling top end torches at high prices. There were endless cheap Chinese copies and not even copies, all sold under names ending with fire, presumably trying to associate themselves with the Surefire brand. Ultrafire, Skyfire, Nitefire, (almost any word you can think of) fire. Not all of them were rubbish, but most were. A lot of the 18650 batteries sold on ebay with unbelievable capacities, were badged something ending in fire.

To make the thread somewhat TE related, I very often use the Eagle Eye and Convoy S2 to look inside TE I'm working on. They are small, the low setting gives plenty of light for that, and it's much handier than angling a desk light round.

I have one from AliX, that I bought after watching a mikeselectricstuff vid.

It's a beast, you can feel the heat off it, and Mike was scorching paper with his.

It weighs in at 1144g, uses 4x 2S 18650 packs in parallel, and can be used as a power bank.

AA for scale in the pic.

Looks useful for dealing with burglars, too.

EC8010 wrote: ↑Wed Sep 02, 2026 9:50 am I used to keep a six D cell Maglite by the bed, but the batteries failed, swelled, and couldn't be got out...

When it comes to lies, its seems torches are even more creative than 1970s amplifiers with their music power, peak power, and Sinclair watts. But I have to admit that my little 3W LED torches powered by a single 18650 lithium cell are way brighter than the big Maglite and you definitely don't want to accidentally look straight into them. But they wouldn't be any good for subduing a burglar.

My D3 Maglite has a LED blub now. It's brighter than ever, and holds batteries forever, and still has violence capital. Useful compromise.

In my belt there are

• a Leatherman Charge Ti,
• sometimes a portable TE Thing called a Sound Bullet,
• a small LedLenser T2, which is plenty strong, holds batteries for months, and is quite useful.

The Maglite comes out very seldomly.

Thinking of unwelcome visitors turning up in the middle of the night and how one could defend oneself in the circumstances, thoughts turn to Bruce Lee and Nunchucks.

https://www.youtube.com/watch?v=LIKQzk-6btQ

A couple of pairs of Mega Lumen lumen flashlights, in BRAINFREEZING strobe mode, each linked together with a piece of chain, demonstrated with a few basic passes over the shoulders. Any halfway sensible burglar wouldn't hang around to see what came next.

It's an idea for selling stuff on ebay. I'm surprised it hasn't been thought of already.

Many years ago, I lived in a student house that had already been burgled once. One night, I heard a suspicious noise from downstairs, so (armed with large frying pan) I went to investigate. I found a very nervous-looking housemate who had locked himself out.

I saw in a newspaper that one of my ex-students had been burgled. He's a big fellow and managed to chase the three burglars off even though one tried to attack him with an acid spray. On that basis, thumping a burglar with a large torch is pretty kind.

Murky waters involving poorly defined terms such as "reasonable force" and tests such as "what would the reasonable man do?".

https://www.gov.uk/reasonable-force-against-intruders

You can "protect yourself ‘in the heat of the moment’ - this includes using an object as a weapon".

The object could arguably be a Maglite or a frying pan, but a billhook would be a stretch.

I think "reasonable" in this instance would be using an object that you might reasonably expect to find lying conveniently to hand in a house. It makes obvious sense to keep a torch by your bed. And frying pans are common in kitchens, although this specific one was thin much-annealed aluminium and would probably have registered an impression of the burglar's face, like a cartoon frying pan. A cast iron pan for an induction hob would be more effective. As you say, a billhook would be a bit of stretch.

OK, Amazon has just been, and I can tell you that the torch Tom referred to https://www.amazon.co.uk/gp/aw/d/B0FC5Z8GFQ is freaking awesome; you really don't want to look directly at the beam on full power; you would certainly regret doing that.

The other LED torch I thought was powerful looks puny by comparison and has a single 18650 battery, whereas the new one has a single 26550 battery with a 5000 mAh rating, and it can also be used as a power bank for phone charging if needed.

So thanks for the link, Tom, much appreciated. Not that I'm scared of being burgled; I purchased 2 of them, as it is always handy to have a powerful torch around the house. The general-purpose string of "tungsten" LEDS built into the main body makes a pretty effective emergency light in the event of a power cut.

EC8010 wrote: ↑Thu Sep 03, 2026 7:24 pm Looks useful for dealing with burglars, too.

Indeed. You've even got the choice of either permanently blinding them, or braining them with it!

Specmaster wrote: ↑Fri Sep 04, 2026 4:57 pm So thanks for the link, Tom, much appreciated. Not that I'm scared of being burgled; I purchased 2 of them, as it is always handy to have a powerful torch around the house. The general-purpose string of "tungsten" LEDS built into the main body makes a pretty effective emergency light in the event of a power cut.

You're welcome.

Note the current consumption of the LED string vs the minimum brightness main beam. I'll bet the minimum illumination would be sufficient in many circumstances.

The evenness of the defocussed main beam is impressive.

Alternative emergency illumination
https://www.screwfix.com/p/luceco-recha ... 50lm/970jk
or chop a flexible strip of LEDs to a suitable length and use a 12V lead acid battery. Use a switching regulator to drop the voltage and save current.

AVGresponding wrote: ↑Fri Sep 04, 2026 5:48 pm

EC8010 wrote: ↑Thu Sep 03, 2026 7:24 pm Looks useful for dealing with burglars, too.

Indeed. You've even got the choice of either permanently blinding them, or braining them with it!

Not to mention brainfreezing them with the strobe or giving them a Megavolt stunning shock, should you select one of the other ebay/Amazon offerings, more directly positioned to home defence.