Review: Ultrafire WF-501B with 5-mode MC-E drop-in

Disconnect the meter and see if it gets any brighter with a wall bounce or something? You could use your camera to help presuming you can set everything manually.

BTW is that voltage when being driven?

Awesome review brted! Very professional and great pics and usual. Thanks! Sticky'd and Frontpage'd. Sorry I missed it until now, feel free to PM me if a nice review slips by me.

Sorry for the late answer, I've been a bit busy the last few days. The batteries where fresh of the charger at 4,2V. After looking at the driver schematics and dusting off the knowledge from the basic EE course I had to take in university, I can see no obvious reason why removing the diode should increase the current through the LED.

You are right, as long as VBatt - VDiode - VMCU > 2,7V, the AMC should work as expected. Without a component level schematic of the AMC it's really impossible to tell what's going on here. All I can offer is an educated guess.

According to the data sheet, the AMC's OUT-pin needs to be buffered with a capacitor if the leads to and from the LED are longer than 10cm and 3cm, resp. The 101-AK is missing these caps and due to a seperate pill and reflector assembly in my torch, the leads are more than 10cm long. Maybe this caused some instability in regulation that vanished when Vdd was slightly raised? I should try soldering some 1µF SMD caps between the chip's OUT and GND pins...

I borrowed a friend's DMM and it has big 18 gauge leads (rated for 20A). Using his DMM I got about 2.8A and then using his leads on my meter I was getting about 3A direct driving the LED with a 18650 battery at 4.06V (at rest). So it's all in the leads. I won't have a chance to solder the drop-in back together and do tests on it for a little while, so for now just ignore my current readings because they are not right. I didn't realize it would make that big a difference. Also I kind of wonder if my DMM is calibrated somehow for its tiny leads and if I start using big leads, will I be getting numbers that are wrong in the other direction?

Best bet is to check it against something known, or at least something you can trust more. Low resistance in the meter and leads is not important for voltage measurements where you want the resistance to be as high as possible. For current measurements you want it to be as low as possible. When a meter is measuring current it is in fact measuring voltage over a shunt which is a (hopefully) high precision resistor with a low value, usually around 0.05-0.5 ohms. An external shunt is probably the best way to go and some nice heavy wire to connect the shunt into the circuit.

I think I will have to invest in new leads for my multi meter as well got my MC-E today shows 1.4a draw.

How bright is your light? Do you have other lights you can compare it to? Does it have that donut hole in the beam? Sorry for all the questions

These leads at DX seem like they are pretty good. I have some on the way now. The writing on the wires in the user picture shows 18AWG which would be 18 gauge wire. That should be plenty.

http://www.dealextreme.com/details.dx/sku.33451

I also bought some leads on eBay that look just like those, but even though they are listed as 10 amp leads, they have thick looking leads that are all insulation around very thin wires and can't measure the current either (I stripped the insulation and figure they are about 26 gauge wire). I told the seller about this and they agreed to send me 20 amp leads which they confirmed had much thicker copper inside. I got the 10A leads for $1.28 at auction whereas they sell the 20A leads for $6.99 so that was pretty nice of them (but they got me to change my negative review of them). Once I get some of the new leads I will do the tests again and post the results.

It is BRIGHT. When it stops raining I will do a comparison shots with it up against my R5's. Yes has a hole, but I suspect that can be fixed by removing alot of heat sink goop.(its everywhere emitter too high)

no worries

Ordering a better set leads from dx .

Got the new multimeter leads today and rechecked the draw on my MC-E shows 2.30A now. Its bright I'am happy

DX doesn't have any more in stock! I ordered on 8/16 and the status still shows

Processing - Awaiting Stock

I have been waiting for a cpl of drivers since 29/4/10 and I suspect you will get your 501b before I get the drivers..

I was so pleased with my DX 501B MC-E M bin that I bought three more to get the drop-ins to install in Solarforce or 504B bodies.The current drop-in seems to be just as good or the same as the original batch.I don't hear any whine like others have noticed and they don't seem to get any hotter than my DX R2s or my Solarforce R5s.They do have a small dark donut hole,but it is a small drawback considering the huge light output.I use them on bikes in tandem with a Solarforce R5 or R2 which fills any donut hole nicely.So be patient, DX is shipping them out!

Mine too only pulls 1.4 amps so will try the driver upgrade...

New driver fitted but still only getting 1.4amps could it be the battery ? i'm currently using trustfire protected with the flame packaging..

Is your multimeter getting good readings? mine showed 1.4a before I got better leads.Now shows 2.3a

Think so it;s always been ok in the past, i've tried to run the light on primaries but it hardly works at all on them ...

This is the new driver that i installed

http://www.shiningbeam.com/servlet/the-132/3-dsh-Mode-Regulated-Circuit-Board/Detail

I see that Maplin is selling the decent DX leads for 5x what DX sells them for.

I bought a couple of pairs and tossed the junk ones that came with the meters.

But bought a USB "microscope" in a Maplin sale.

But the light also doesn't seem any brighter in fact i would say it's no brighter than the R5 drop in that i had in the body before

I really think its the leads. Seems to be a common problem. They seem fine till the amps get up,but then just keep showing low readings.

How bright is it? Won't be brighter than an R5 but should give HEAPS of flood.