ALXM2 P60 runtime graph (5x7135). Updated with Sanyo 2600 mAh

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JanBLF
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ALXM2 P60 runtime graph (5x7135). Updated with Sanyo 2600 mAh

Update in post 5

Finally after 5 weeks of waiting, my order for an ALXM2 P60 (3c tint) arrived from IOS. I’m a sucker for regulated constant output runtime and I despise that ever declining output from the moment you turn on the flashlight. So after a brief test to see that nice 3c tint and the output, I went ahead and put the module through a runtime test. The host is a Surefire C2 bored out for 18650, and light was placed on a wet sponge (for basic ‘hand like’ cooling) 1 meter from my lux meter using a fully charged AW 18650 (3100 mAh) cell.

Initial output was of course nice and bright and the output was relatively constant – for the first 5 minutes! Then the dreaded and disappointing (to me) decline in output began. I hate to break this to all flat regulation lovers, but a normal and good brand 18650 won’t run this module in regulation for very long at 3 amps. I stopped the runtime test at this point. As I want a relatively flat output for at least 60 min. I decided to de-solder 3 of the AMC7135 (380mA) chips bringing the current down to about 1900 mA to the led. Things now started to look much better. Of course output would initially be slightly lower than stock 8×7135 but now I got what I aimed for (60 min. constant output) and a more manageable flashlight temperature.

One could argue why not just go to a lower mode to get a longer regulated runtime, but unfortunately this won’t work because the PWM driver is still trying to deliver 3A to the led on every pulse in the PWM cycle and therefore this will also result in the ever declining output starting just a little later. The best solution for longer constant output is to de-solder some of the 7135 chips. I took a measurement of the tailcap current with the 5×7135 and it showed 1880 mA so it’s nicely within spec.

Here is the runtime graph with 5×7135 on a AW18650-31. I have ordered a Sanyo UR18650FM (2600 mAh) and will update this graph when I receive it. The 2600 mAh cell should retain a higher voltage longer than the 3100 mAh so maybe the regulated runtime will be extended somewhat – we shall see.

Jan

Edited by: JanBLF on 01/06/2014 - 15:46
benz
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Thanks for doing this test!

Tom E
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This is interesting to see, thanx! Was the pill wrapped? Aluminum, or preferred copper will make a big difference - comparative tests posted here have shown.

JanBLF
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Yes the module was wrapped with copper and a thin layer of alu to make fit really tight, Pill with thermal paste on the threads.

jacktheclipper
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Thanks for sharing .

What I do

 

JanBLF
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As expected the 2600 mAh (Sanyo UR18650FM) is retaining the voltage for longer and thus is better at keeping the driver in regulation. Once it drops out of regulation the cell is practically completely drained as seen by the rapid decline in output. I’m very pleased with the constant output for 75 minutes using the Sanyo cell, however this battery is without a protection circuit so another 2600mAh 18650 with protection circuit may have a higher internal resistance and therefore not keeping the driver in regulation as long. As also seen in the graph the ALXM2 with Qlite driver drops down to low when the voltage gets below 3 volts so I’m not so worried about using a non-protected cell in this light.

Hikelite
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JanBLF wrote:
As expected the 2600 mAh...........

Nice post JanBLF, with great observations.