Single 18650 max current output 2.8amps?

Flashlight Modding and DIY Parts
1

Hi all,

I’ve just done a parallel triple nichia on two setups:

1. Direct drive (no driver) (100%)
2. 12 x 7135 nlite 4.5a driver with same battery (100%)

Both are using the same Nitecore 2400mah 18650 battery, copper wires to leads and have copper wire soldered to the springs

Upon measuring both tail caps with a DMM, it seems like both of them draw 2.8a max, tried it with another similar fully charged eagletac 18650 and its still max at 2.8amps

I understand that direct drive will be the brightest as driver does not “amplify” current, but is there a reason why the max draw for direct drive is 2.8amps for both? How are others getting 4-5amps on a single 18650?? :

Tried to change the emiter to an XP-L and reading is almost the same at 2.7amps, perhaps I need to use an IMR 18650 instead? Something seems to be limiting the current draw… the emitter?

Cheers!

2

The typical thing is DMM wires..

3

Stock leads on your DMM?

If so, they are probably inadequate for measuring tailcap current.

4

Hi guys thanks for the replies…

Hmm… yeah it could be the DMM being funny too…

I just measured my convoy m2 with an MT-G2 running two IMR 18350s directly driven, 4.8amps?

5

The MT-G2 has a Vf of like 6V, so I’m assuming that the 18350s were in series. The series batteries would give about 7.4 - 8.4V, so the pair could sag more and still keep the MT-G2 Vf high enough to be over-driven.

6

Yes.

4V and 5A is not the same with 8V and 5A. You have more to lose from 4V.

Now cell power also matters. I am not sure what sort of power Nitecore 2400mAh has.

None the less do not expect 4.8A to travel through 2 meters (back and forth) of 22AWG typical DMM leads. Use short (1feet) and thick (12-14AWG) leads.

7

Typical DMM leads are actually only around 28AWG (about 20-40strand wires), they only appear larger cause they have extra thick casing.

ghos I would point you towards the external shunt resistor modded DMM’s I sell here. Note I make no money on them so I’m not just pushing for a sale, they’re very useful tools to have around for all sorts of current measurements, not just for flashlights. Also all meters shipped from this point forward will be the newest version of HF meter.

8

Was the wires from the emitter to the star also thickened? Choke point for current can also be there

9

Well the wires aren’t exactly very thick but its being run parallel, so there’s actually two wires to each emitter all wired to the base plate for a total of 6 wires, meaning more paths for the current to flow…

Its a very simple setup actually, batteries to emitters to DMM, no drivers or switches, if its really 2.8amps meaning each LED is only seeing 0.9amps… which makes it mind boggling… unless of course i were to wire it in series but that would probably poof the LED or something

10

Do a ceiling bounce output test with the tail cap in place then again using the DMM to make contact, I bet there is a considerable lumen loss when the DMM is used, this would prove the problem limiting current is the DMM.

11

You can also short the DMM leads together while measuring current, if the light gets brighter than that's how much the meter is eating up.

12

Hmm probably would be the case but right now I don’t have access to the DMM now (in office)… Will try again next week once

13

Yeah didn’t thought of doing that, but what makes me suspect is that the apparent brightness between a XML running at 4.5amps vs a stock 3amp should be nearly 500-700 lumens? I did a bounce test for a nitecore light rated at approx 800 lumens using the same battery and both appear the same :~