Well if you get a chance to measure it then just let us know. The resistor mod is much easier than dealing with a pot and dialing it in. It’s kind of hard to find an smd r220 resistor so i’m just going to order the mini-melf 1/4w .22ohm.
Thank you Werner. 8)
I have measured current…exactly 3 Ampere through the LED on high :party:
Measured at 8 V input
Mode . . . . Current through LED
High . . . . . . 3 A
Med . . . . . . 1.47A
Low . . . . . . 0.29A
Current through LED is constant through whole voltage range. Sometimes the DMM showed 2.98A and sometimes 3.02A.
I have let it run some minutes to let it get hot, no big difference
As I was to lazy to pull driver out again I soldered the amp-meter on top on the LED (oh I am so smart H) ). Forward voltage was 3.1V on high, that’s about 84% efficiency.
could you test that at 4v input? im curious as to what will happen when i make it a shorty. wondering if i can get away with using one 18650 or need two cells. possible to also try 6.4v input?
I have it put back together, but I have tested whole voltage range just took no notes. Just for info it’s 2AM here.
When i remember correctly until 5V it was still 3A.
On some point there was even a small peak of 3.2 A at about 4.5V after that it dims.
Not possible to use one cell with this driver on this brightness, but there are many one cell drivers available which are cheap and good.
What do you plan with 6.4V? That would work as I tested 6to 10V often.
6.4 would be 2 x lifepo4s nominal voltage. judging by eye, i cant notice any difference on one cell or two. but my eyes may deceive me… i havent opened up the driver and done any modding or current tests yet though either
i need to take a pic of the shorty with aspheric head, by my girl has my phone and shes laid up in bed and im not going to force it from her lol.
later tonight ill post a pic i got of it… gotta mail the head back to get a new one though
Great job. Thanks for checking the current. I’m going to order one of those .22ohm mini-Milf resistors now.
hey guys, i think this a relative question in this thread. i want to put a red xp-e in my zy-t13. it has a vf 0f 2.3v and i would like to run it at 1.4-1.5A. the driver in this light has two r220 resistors. any suggestion what i would need to do to achieve my goal would be appreciated.
Are you familiar with measuring current through the LeD?
Than you could replace one of the resistors with a pot and adjust it until you have your favorite current.
One first quick try could be, to remove one of the R220, this should give you half the current it is on stock so about 1.2A
What for do you need a red thrower?
I would guess a red thrower for coyote spotting at night? Red doesn’t spook them as easily
resistor…
so the finally resistor would be … it should be around 0.07ohm correct?
1/.22 + 1/.22 + 1.22 = 0.07 ohm.
1÷(1÷0.22+1÷0.22+1÷0.22)=0.0733333333333333333333333333333333
So yes it should be about 0.07 ohm
so, the lower the sense resistor the more currents.
stock = 0.11 ohm
mod = 0.07 or less if want bright
mod = 0.11 or more if want dim.
kong
if I understood correctly you are actually adding resistor or varistor (potentiometer) so you are increasing resistance!
I am talking about the final resistance of the sense resistor… if you add .01 parallel to the current resistor 1/ ( 1/.22 + 1/.22 + 1/.1) = 0.0523… which is less then 0.07ohm,and it is brighter…
Yes I am familiar with measuring current through LED. I like your suggestion of removing one of the r220. Could I add the trim pot in place of the removed r220 to fine tune what I need? I am a bit confused though, you are saying lowering resistance increases output amperage. I would have thought just the opposite
I did a quick test. Just a simple emitter swap. Red xp-e an stock driver exactly same reading as with the xm-l. 3v and .96A tail cap on high. Way to much for a red xpe. Start up lux was over 20k and quickly dropped to 14k and I shut it down before failure. Then I put the green xp-e in same reading but ran very good. Start up was over 30k and held it without dropping.
EDIT: sorry. i get it now. these are parallel not series. my bad.
Red thrower for gun mounted shooting light for night hunting fox and coyote.
Please show some more links of where you bought these resistors,
Just to help out the resistor noobs, like me.
Order one of those and solder on the R220 resistor that is already on the stock driver. Just like werners picture. It should yield ~3.05 amps.
ok. i was able to salvage various rxxx resistors out of old drivers and hand solder them to the board to get exactly the amp draw i was looking for. sweet. thanks to all who contributed in this thread. i am now in love with this driver except for…
next question how to get rid of strobe and SOS and keep high -med-low?