Ultrafire C303

Don which is brighter?

How amps do they both draw ?

The Yezl is a lot brighter. Like 50 lumens more at switch-on. Most I've seen from the Ultrafire is 1200mA on high. I'll try it with other cells and so on when I get around to a review. I really ought to add current draw to the spreadsheets.


The Yezl numbers are:

With a 14500

1380mA

620mA

190mA

With an eneloop

2380mA

1790mA

770mA

In your opinion which driver is more efficent?

Nice Don , looking forward to the review

Wouldn't the old fashion methode be good to analize the material? I mean, mesuring the mass of the body tube, by dunking it in a water container and then put in on a balance to get the exact weight.

That's a very handsome light. I'd take a 1xAA version.

That'd get me the density, but there are so many alloys out there I'd not be able to work out which one without chemical or spectroscopic testing. If there's any iron in it then it is an unusual looking stainless steel. It is just possible that the surface grooving that is causing the colour though it isn't that finely grooved.

If the density is known, I thought it would roughly give the direction to go. Steel, aluminum alloy or titanium.

titanium = 4,50 g/cm3

aluminium = 2,70 g/cm3

stainless steel = 7,80 g/cm³

Now you just have to work out it's volume...time to take a bath :P

I was thinking about mesuring its density before I made the caustic soda comment, but I first dismissed it as unfeasible. Thinking about it again, you actually only need to weigh and submerge the battery tube and not the sensitive head and clicky tail. Much better idea than using caustic chemicals! : )

One could also try testing its resistance at some flat part of its surface, aluminum oxide is a good insulator and should give an "OL" or similar read out while stainless steels should give a very low resistance reading.

My Yezl B6 and B2S Pulled the same kind of amps .On a 14500 that was run down to 3.71 volts on High it pulled 1.290A...med .950A low.160 A... god forbid if I charge that battery up to 4.20 but 3.7 volts is what the emitter wants anyway .

So are you saying this has super knurling ?

My guess is that density is a better bet. Al is a better conductor than Fe and it isn't that hard to penetrate a thin layer of anodising while trying to get a reliable contact. I'll need to go up into the loft and see if I have any measuring cylinders of appropriate size. Whatever the metal is, it has a very high magnetic permeability- which some steels do and many don't. What i mean by this is the NIB magnets I used to test were strongly attracted to the steel cased 18650 inside the light. This doesn't normally happen with Al lights though they tend to be thicker walled.

I certainly don't intend to strip out all the internals so only intend to measure the battery tube. Because of the fine grooving I'm going to have to boil it to shift any entrained air. A drop of two of a surfactant (AKA dish washing detergent) will also help here. But unless I can find a reasonably precise measuring cylinder with a large enough diameter (So the battery tube will fit in it) to measure the displaced water, there is no point in trying. Kitchen equipment will not be up to the job. Somewhere in the loft there is a 70 year old lab balance and weights for it - there may just be some volumetric equipment as well.

I'll take a look in the loft at the weekend unless anyone has access to non-destructive elemental analysis gear. I doubt anyone has such kit at home as it'd cost more than the house did.

It isn't really knurling - it is a fine grooving over all of it - even the knurled portions have the fine grooving on them. Here's an 80x magnification picture of a part of the head.

I have access to precision scales and a couple of these measuring cylinders in various sizes:

I'll test it as soon as it arrives, unless someone does it before it arrives.

I've found it to be very useful to keep some lab glassware around for everyday stuff : )

I don't really have anything meaningful to contribute to this discussion but I'd like to get two things off my chest. ;)

1. I just showed this thread to my wife and she thinks we're all nuts. And that's coming from someone with a medical degree.

2. I officially love this forum. :D :)

Love it. I spend my days with psychiatrists several of whom want to get me on medication....

Ain't happening....

Most of my patients think I need meds....

I assume that your car had a rather expensive repair bill. Sorry to hear about that!

After looking at the magnified pic that you took, I wonder if this was stamped or pressed in a mold from a metallic powder alloy and then kiln baked - as many parts in the automotive industry are these days.

I hope you feel better mate.

Around $2000. Cylinder head is toast. :(

I feel sorry for the Chinese who buy these motors - the factory got sold and moved to China. They get sold in China as the Roewe 750 . The 2.2 and 2.6 litre motors are fine but the 1800i motor is a POS by design. Guess which motor mine has?

Pity BMW in the brief years that they owned Rover didn't just substitute their well sorted 1800 fuel injected motor for Rover's sabotaged on the drawing board design. Not to mention the German made porous cylinder castings - they built what was designed - which is a pity. The diesel motor was a BMW engine - the petrol (gasoline) one wasn't.

I think given Chinese labour costs it's more likely that it was machined by hand rather then sintered and stamped. Sintering and stamping costs an enormous amount in hardware. Machinists are very, very cheap...

Anywhere else on the planet (except maybe India) it'd be far cheaper to sinter and stamp it. I'd guess it is most likely hand machined. At what a machinist charges here they'd need to make about 8 of them an hour to cover their labour costs. I'd guess the factory makes that many of these per minute for the same labour cost.

Concerning the metal...

I've got access to a mass spectrometer at work, but that would entail vaporizing a small portion of the light - no good.

But...since the thermal conductivity of titanium is roughly one tenth that of a typical aluminum alloy, the easiest way to tell might be a simple "match"

So did I but it is nearly 30 years since I stopped being a chemist and I broke pretty much all of the stuff that got "borrowed" from the various places I worked in. The stuff in the loft belonged to my great uncle whose house this was - he bought the house outright in 1936 for 35% less than I spend a month on the mortgage payments for the same building. He was a chemist for the local soap manufacturer - "Soapy Ogstons".

The remaining gear ("gear" is the local junkie's euphemism for heroin BTW) in the loft is more than 70 years old so is calibrated in strange (To someone who thinks in SI units) units.

I can still remember trying to stay awake in all those sampling theory and methods lectures in 1979. Rather often, I failed to do so....