Amps at tailcap question (low readings with crappy DMM)

LED Flashlights – General Info
1

I know this is a complicated question, and I’ve read every thread I can find on the subject, including HKJ’s wonderful tutorial.

I also know a crappy Astro AI DMM is not a great device for measuring current.

Still…

I’m getting really low readings at the tailcap on my Jaxman E3 with a DrJones H17Fx Driver (brass button connection, not a spring), DTP MCPCB, and LH351D 4000k emitter. I’ve put a fully charged Vapcell H10 (10A continuous discharge) in, connected the DMM properly to complete the circuit, and gotten it to turbo (full FET) and only clocked just under 3A on the DMM.

Am I just using the wrong tool for the job? FWIW, my D4v2 (SST-20 3000k/4000k mix) with freshly charged 30Q battery reads under 5A on turbo, as well. It didn’t blow the fuse on the 10A max DMM, which is cool, but it seems incredibly low.

Am I on a fool’s errand even using this device for current measurement? The leads are very long, and definitely shitty…

Any advice is welcome! Including is this is the wrong sub forum for this question…

2

You need a clamp meter and a short piece of thick wire to measure the current. In-line meters have too much resistance.

3

I have even experienced that with professional multimeters, it’s just not the correct tool for the job.
Get a cheap UT210E and see the difference

4

Cool. That makes sense. I figured I just didn’t have the right tool for the job.

So I can completely discount the readings I’m getting, huh?

How short and how thick? Like 1ft and 14AWG? The shorter the better? The thicker the better?

5

You just have to bridge the battery with the flashlight. The shorter and thicker the better it is.

6

here is a guy who takes tailcap readings seriously, maybe it will spark some ideas to help you

7

Is this “Signstek” UT210E the same as the clamp meter you’re recommending? Just want to make sure I pick up the right one!

Cool, thanks!

Nice. I will check it out. Thank you.

8

The original UT210E is from brand Uni-T !
That seems similar, price is equivalent, but brand is not the same.

About the suggestions, for measurement, as mentioned above, for tailcap readings (not parasitic drain but current draw while on), short and thick wire is better, not probes. Check this video (minute 5:15):

:+1:

9

It looks the same, it carries the same name, but its not an UNI T (their products all start with their initials UT)
https://www.uni-trend.com/html/product/General_Meters/digitalclampmeters/UT210_Series/UT210E.html

On AE you should be able to get it for 35 USD or so.

10

I am looking for one and some stores will have it bellow that on 11.11. I am looking for one that can be shipped from spain and it will be around 33€ :money_mouth_face:

11

Ah, I see. Thank you! I will look for a UNI-T UT210E.

And thanks for the video, MascaratumB! I’ll get some thick AWG wire and go to town measure tailcap amps.

12

I grabbed a UNI-T UT210E from Amazon. Thanks for the recommendation, everyone!