This one from ebay.

I have and use a Trouty light which is powerful but quite flood like. However I prefer to use both a bar and a helmet light, so I wanted a somewhat spot-like one for my helmet. I’ve been using a commuter light but having a built-in battery it was heavy and annoying – plus it only had a 1 hour runtime on high.

I’ve accquired several high quality batteries over the years which are still fine although the HID lamps went the way of all HID lamps, so I thought a cheap ebay job would be worth a punt since I don’t care if the battery or charger is rubbish. I specifically wanted a small light unit, and I didn’t want it to overpower my bar light so I wasn’t so keen on the Solarstorm twin job that seems the most common. This thing is light enough so it doesn’t wobble around when running.

The light came in a couple of days and I was quite surprised with the quality of the lamp unit. It’s as light as I could expect, nicely machined out of alu and has o-ring seals where needed. The bar clamp is rubber band based like the Lupine ones but you can easily un-hook the rubber band and change it for a different size, unlike Lupine. It also came with a headtorch mounting strap which is pretty small and tight on my big head but pretty secure, and possibly tolerable for longer term wear. Thanks to the bar style fitting though I’ll be using my old Lupine helmet mount.

The downside though is the beam pattern. It’s a pretty small bright spot, with a quite large and evenly spread (but much dimmer) cone. This wouldn’t be so bad (in fact would probably be perfect) if there were a nice gradual transition between the spot and the flood, but there isn’t. I may try and modify this a bit later – turns out lenses are widely avaialble on ebay for pennies so I may attempt to replace the flat glass cover with a converging lens or something.

Anyway having just taken it down the path to check the beam pattern it might work out okay for helmet use. I usually set my helmet light to look way way down the trail, and here the spot is less of a problem of course.

As I was swapping connectors over I measured the current draw. It was about an amp on high and a remarkable 330mA on low!

So I’ll provisionally recommend the lamp unit for helmet use on account of its pleasingly low weight, stupidly low cost and adaptability for running. I’ll see if I can get hold of a really small battery that I can stick in a Spibelt for running use – it only needs to be a couple of Ah.

EDIt hmm.. just checked the specs for the LED on the Cree website, and it says it’s 1000lm at a current of 3A. But I measured it at only 1A so I guess that means only 300lm. However it looks way more than this.

The cable is very very thin indeed and I did wonder if that was limiting current – given the measured current is so much lower than the spec for the lamp – perhaps it is.

EDIt hmm.. just checked the specs for the LED on the Cree website, and it says it’s 1000lm at a current of 3A. But I measured it at only 1A so I guess that means only 300lm. However it looks way more than this.

Depends where you took the measurement, before or after the driver.

How so?

Actual data sheet suggests 385lm at 1000mA and 85C

For example… 9v battery at 1A going into driver, 3v at 3A after driver going to LED.

How can it increase the current then if it’s not a transformer? Surely current has to remain constant in the same circuit?

the specs say 2.8amp with a 8.8a battery, so if you light at full power lasts 3 hours then i suspect you got your 1a wrong or you got a incoret speced batery.

Their page says 8.8Ah battery and 3 hour runtime which implies about 3A. However I measured the current with a multimeter in series and got 1A. I guess it’s possible my multimeter leads added resistance perhaps. Although they are bigger than the tiny wires it comes with.

Seems entirely possible that they’ve built the light on the cheap, with cheap wires, and this is reducing the light output from what’s claimed. Doesn’t seem remotely feasible to get 3A down these tiny conductors. Although tbh it’s bright enough.

The xml takes 3a at 2.8v (about 9w). If you’re measuring 1a at 8.8v (about 9w) that should tell you what the driver is doing.

It is a “transformer” in a practical sense (even if it doesn’t have multiple coils on a ferrite). There are indeed two sides to the circuit, one with a higher current than the other. If you want the technical details, google “buck converter”.

f you want the technical details, google “buck converter”.

Cool.. that is clever.. always wondered how they actually worked – I’d assumed it was just PWM.

Thanks.. so the numbers do add up then more or less. I should be getting a decent fraction of those theoretical 1000lm then..

I, and 2 other friends have the exact same light….none of us have had any issues with ours. Id happily recommend it too.

What size is the lens? You may be able to swap it out for a wide angle lens if you want a different beam.

I bought one of those 2 years ago for £13.
I didn’t think to write an essay on it though. Just fitted it to my roadbike and used it 3-5 times every week ever since.

I wrote an essay or ‘review’ as other people would call it, in case anyone else was looking for a similar thing and was unsure of which of the super cheap options would be not total crap. I thought this was a reasonable thing to do, I apologise if not.

@hypnotoad, glass diameter is 39mm, unlike any of the lenses for sale on ebay. 50mm seems to be the thing.

You should have got the Solarstorm – it’s not really any bigger and has a nice spread of light. Sorry. 🙂

I put one of the aftermarket lens’s in mine and it was much better than the one supplied,
No idea which one cos it was ages ago but it works well on my head with my Trouted Hope X2 on the bars..

a review? you haven’t even used the thing 😆

Alright. First impressions then. I’ll type the rest when I ride with it. Now get back in your box.

Grum.. Yeah possibly. Surely must be heavier tho.

Khani, what lens did you get?

I don’t know, it was a few years ago and I can’t remember now, 😳
This is it if it’s any help

Ah yeah.. Found that one on Amazon. Ordered, ta.

beam shot comparison with the different lenses please?
also does it come with the headband? whats it like for running as i also run, fit and usability over brightness, as im sure its bright enough.
ta