This weekend I decided upgrade my UltraFire drop-in from Manafont with a modified Nanjg 105c because I was one of those unlucky few who received a MF UF drop-in with aps of:
High: +- 1.6 A
Medium: +- 0.5 A
Low: +- 0.15 A
(measured by a Fluke 177)
This is how the LED of the drop-in looks:
And this is the driver board used:
(anyone able to explain the driver board? Is it a linear direct drive?)
So after we've piggybacked 2 x 7135's to the 105c to make a 3.5A driver, we connected the LED and measured the modes:
High: +- 1.9 A
Medium: +- 0.6 A
Low: +- 0.08 A
We checked every solderpoint, and all looked good, but assumed we screwed up with the soldering, and connected a spare stock Nanjg 105c which should pull 2.8A on high. To our surprises we got exactly the same measurements. This was measured with only the LED, driver board and battery, no drop-in pill, host or anything else.
I have read a thread on BLF that the resistance in DMM cables can give untrue readings, but if that's the case, shouldn't the low and medium modes read correctly as (5/100 x 3.5) = 0.175A and (30/100 x 3.5) = 1.05A on the DMM?
So I'm really now starting to wonder what can be the issue. I have to assume now that my MF UF drop-in could well have been able to pull over 3A's. The only unchanged components is the LED and battery, and I've never heard of LED's not being able to take more current. So my TrustFire 2400mah Flames must either be dud's, or they're fakes They are literaly brand new (2 months), only been charged 3-4 times each and never discharged below 3.6v
Nope, It would read as a portion of the High Current Setting. In this case, about 5 and 30 percent of that number - 0.57 Amps and .095 Amps respectively.
The reason for this is that the driver uses PWM to control the brightness. It turns the circuit ON (High Mode) and Off (NO Current) very quickly. PWM is done very quickly, and your eyes average the output to make it look like it's only 5% as bright all the time, rather than 100% as bright 5% of the time.
Because of this, You get 1.9A when it's on, and 0.0A When it's off. Your numbers are pretty darn perfect. The Fluke meter (or any other DMM) does the same thing your eyes do, and it averages the current to display exactly what you're seeing. If you were measuring the current with a high-speed oscilloscope, you'd see bursts to 1.9A and troughs to 0A - but again, if you averaged those readings across time, you'd get .57A and .095A
I guess I'm a butthead because I gave up on the aluminum/copper foil wrap method and I'm running my drop-ins naked now. I came to the conclusion that the concept of the drop-in is convenience so therefore I'm going with total plug 'n play now. I don't operate my flashlights at such long duration's so I'll just risk the emitter being fried. Maybe it's just an OCD thing for me
Thanks for that PPtk. So does that still mean it could either be the battery or the Fluke reading incorrectly? What can I do to get a more accurate reading?
It's impossible to know for sure without seeing it, but my suspicion really would be the DMM leads.
Have any nice thick wire? 10..12..14Ga? Doesn't matter what kind..
If you do, cut two pieces about a foot long each. Strip off about 1/2" from one end of each piece, and shove it in the holes of the DMM where the leads should usually go. Strip just enough of the other end to be able to press it against the back of the battery and the flashlight tube. None of these voltages are ANYWHERE NEAR enough to hurt you - so don't worry about touching the wires.
That's it.. Pretend the wires are the DMM probes, and stick them on the battery and the tube - see if your readings change - hopefully higher. If they get even a bit higher - not necessarily all the way to 3.5A, but say, to 2.5A - then I'm 99.99% certain that its the DMM leads causing your measurement error.
I will also add that it will be helpful to "tin" the ends of those wires (ie. apply solder so the individual strands aren't coming apart). I did this trick with my meter (except that I bought banana plug ends to solder on for the meter connection) and saw quite a large increase in my readings. In that link I just jammed in some 14 gauge home electrical wire. Since then I made my own test leads using regular 12 gauge wire. Also learned that one of my cheap meters is junk and should never be used for current readings.
My UF MF XML dropin measures 3+A with no issues. I found that the single 18650 cell I got from DD with my $5 502b host could only push the amount of current you are describing. I eventually discarded that cell and am using only cells capable of providing the higher amount of current.
If you have a spare XM-L emitter, try a Direct Drive connection and test the current your cell is able to provide in that configuration. My first suspicion would be the cell.
<edited to add>My DMM is a cheap older $12 model with standard leads, and is still able to read the current accurately.
I also would try chaging the DMM lead first. They may be resisting the current during testing.
I've tested my cheap DMM leads for resistance, they're measured around 1.8ohm. Considering we're only using a lowly 3.7V voltage, that's a wee bit too high.
On the other hand, a simple household wire 1.25mm2 just pushed tightly into the probe gave 0.2ohm, much much lower resistance.
As expected, when testing tailcap current, the cheap lead only gave around 1.4A for the MF drop-in, and the household wires gave 3.6A.
Ok guys, I've got some updates. I measured the cell we used to test the new Nanjg 105c and it was only 3.7v, . My used and charged cells must have gotten mixed up . Charged the cell fully and let it rest for a day. Resting voltage was 4.15v, and here are my results.
Manafont driver board, full battery (done a few weeks ago), thin cheap dmm lead: High: 1.6-1.7A
Ok cool, so the Flames are able to supply the current, and my new 3.5A board is working. The guestion I can't answer now, is whether my original would have been able to pull over 3A's. But I'm pretty sure when we measured it with full batteries a few weeks ago with my cheapo dmm and the Fluke, we measured 1.6 - 1.7A.
I'll take some beamshots tonight so that I can compare it with some I took a while back of the original board.
Ok, I've taken some beamshots. I must say, in real life the new 3.5A Nanjg 105c is definitely brighter. For the first time I see rings in the spill caused by the reflector. Based on the shots, I would say that the Manafont drop-in probably drew close to 2.5-3A's, and the Nanjg 3.5A's. Please bare in mind that all fotos are taken with my automatic Panasonic Lumix ZS3. Settings seems to be Shutter speed is 1/8s, Aperature is f3.3, and ISO400 on all photos.
I'll let the photos do the rest of the talking. Enjoy...
The 6mm include the plastic around the wires, the copper part itself is only about 4mm, but yes, it's nice and thick. I just stripped the ends from the wire, pushed one end into the dmm and the other end to make contact with the flashlight. I'm sure if I solder the wire's ends they'll make better connections and read closer to 3.5A
For the first time the flashlight gets hot on High. With the original Ultrafire driver I could leave the light on high for 10-15mins and it would be bare mildly warm. Now, after 5mins on high it's warm.
My Stock MF UF 3-mode heats the flashlight VERY quickly! On mine, the flashlight will be getting noticable warm after 30 seconds. After 5-10 minutes on high, the entire flashlight body is VERY warm and the head is so hot that you can't hold onto it for more than a few seconds.
I just got this sku 5720 from Manafont. It seems to work fine with all my Trustfire Flame batteries (4 of them). When I use it with my DX Gray Ultrafire batteries, it trips the protection on all of them (8 different ones) within 10 seconds when the drop-in is on HIGH and the batteries are fully charged to 4.20V.
Not sure if this will be useful to anyone but I thought I would mention it.
I have finally put this drop-in to use. Mounted with copper foil (tightly squeezed in) in my fake L2. I like it a lot, but I have one issue with it I don't like. The drive current on medium is too high to be "battery conserving".
With a fully charged Tenergy 2600mAh 18650 I get:
High - 5.15A
med - 1.50A
Low - 0.28A
I was hoping for a medium closer to 0.9A -> 1.0A for longer runtime. Perhaps it's just my battery and on a lower quality cell (ie. a Trustfire flame 2400mAh) I'd get lower numbers.
Yes 5 amps. This was a great drop in a year ago when everyone was using cheaper batteries, now that most people have better batteries it pulls way to many amps because it’s direct drive on high. Plus the PWN on medium and low is horrible if you are sensitive to it you should avoid this drop in.
They are literaly brand new (2 months), only been charged 3-4 times each and never discharged below 3.6v
. My used and charged cells must have gotten mixed up 
. Charged the cell fully and let it rest for a day. Resting voltage was 4.15v, and here are my results.
