XM-L T6 - UF WF-501B only drawing 0.5A at tailcap on high

Welcome to your nightmare called BLF.
Could be the battery if there is a problem. What is it and have you checked its voltage?

I tried fresh cells, Readying 4.1V no load

on high 1A, medium 460mA, low 205mA

??

If you’re using nipple top 18650’s, make sure the contact spring at the base of the drop-in is contacting the battery terminal properly. Some of them are soldered on badly and point out at an angle, sometimes barely making contact.

Also, have you been able to confirm that the batteries you are using are capable of delivering above 1A in other devices?

Battery type? Check the drop in/pill

Thanks for your help, from what I can tell the spring is contacting well but yes they are nipple top. Have tried different cells and the most I can get is 1A. haven’t got any other devices to test if the cells can deliver more current.

They are UltraFire XW 18650 cells bought off ebay.

Matt

What is your DMM. Are you using thick wire or standard leads? Might be a 1amp U2 drop in but it would be reasonbly bright.

DMM is a Digitech QM-1536. About $80 worth. Not the best but still ok.

Visually the LED looks identical to pictures of T6 have seen. Not sure if U2 1A look the same?

What would be the advantage to the seller? U2 1A cheaper?

Ta!

Oh and using the standard leads that came with the DMM.

The LED is probably fine. Most likely it’s a cheap crappy driver.

Ah ok,

Was planning on direct driving the LED and seeing what amps it pulls. What do you guys think?

Cheers

It's your emitter. Go for it . XM-L can withstand DD with normal Li-ion. Just don't use low-resistance batteries like the LMR (or IMR).

My MF 3-mode throws like nobody's business after it was dedomed. Probably yours just need the extra amps after all. My high is DD at around 4Amps (up to 4.8A on full NCR18650A).

The readings you are getting are consistent with thin leads. Make some up with thick wire. I’ll bet that will sort it.

Welcome to the madness, rufes1!

Hey again,

Got my Romisen RC-T601 II - XM-L U2 today from Shining Beam and am very happy with the torch.

I had a closer look at the XM-L T6 in the 501B and found the negative terminal solder joints that conduct from the torch case to the circuit board to be very average. One was a dry joint and had come loose and the other wasn’t real great either.

After re-soldering I measured with a Fluke DMM and it measured 1.5A with the standard test leads. I then measured the tailcap current of the Romisen and it also measured 1.5A on high.

So it must be the test leads. I must say I am pretty surprised the leads could make such a difference in the current reading. I am assuming the actual current is more like 3A?

personally, my first thought when I saw *fire cells + eBay was crap batteries. If you can, try and get hold of at least one decent cell (a NCR18650 or equivalent) and test again. If you still get 1.5A then it may be the driver/ connections or your DMM. If you get closer to 3A then it’s your cells.

Aloha and welcome to BLF rufes1!

There isn't a thing wrong with fluke test leads

it's Crap batteries ..

Both lights will scream on real batteries . on a 150 lumen light you might not have noticed junk batteries ..

I also believe it may be your cells. Ebay ultrafire/trustfire can be hit/miss with mostly rebadged salvaged cells. But it could also be your driver. I have a 504b i got from dd and it rocks with my unprotected panasonics.

+1 batteries, I had similar issues with the *fire cells, bought some Xtar ones and all’s ok.

Leads can make a difference. I get 1.6 a with normal leads and 2.8 with short thick leads.