Driver change for 2x26650 XML

[Cooper_GTI]

I recently brought a Keygos M13. It takes 2 x 26650's and uses an XML.

However, it only drives the XML at 1.5A on high, which is pretty feeble.

Now, having never attempted anything like this before, can anyone point me in the right direction of a good driver to give it around 3A on high, 2A on medium and 1A on low.

And also, is there an idiots guide to changing a driver, as this is the first time i've modified anything flashlight related! :wave:

Here is the head of the light...
I'm assuming the gold part with the positive spring is the 'driver'?

 

[tx101]

What is the diameter of the driver ?

If it is 17mm I dont think there are any drivers of that size that will reliably push the LED at a higher level.

 

[Cooper_GTI]

At a guess (as i'm not at home) i'd say it's larger than 17mm.

I take it that all the decent 3A drivers are larger than 17mm in diameter?

If i were to send it to you, could you retro-fit a new driver? 😗

 

[Cooper_GTI]

If it is 17mm, would this do the trick?

...or am i way off the mark?

KD SKU S005296

or this 19mm driver

KD SKU S005296

Please Do Not link directly to sales web site - Norm

 

[yazovyet]

would be best to measure it get somethign the same size. you don't want to get your heart set on a driver thats too big. evan something too small would be troublesome to mount.

That 17mm driver says it uses PMW at 122/244 hz (meaning it turns on and off the full power that many itmes a second). Some people might complain of being able to see or somehow notice this as a bit of a flicker. Otherwise it looks like a good candidate based on the large amount of info they provide.

The 19mm has a strobe and SOS mode, some people like this some people dislike it. There isnt much info about this driver so it is hard to say.

you may have seen the drivers you're looking at have a wider current spread than 3,2,1 amps; I'd say this is a good thing so you can get a nice low mode. I basically came here to recommend getting as wide a spread as you can find.

 

[Cooper_GTI]

Thanks for the reply yaz!

I agree, perhaps it'd be best to get something that had a really 'low' mode to get maximum runtime.

So when measuring, i take it the gold thing (in the pic) with the spring attached is the driver. How do i go about removing this? Is it just a case of unscrewing everything inside till it comes out, or is it likely to be bonded in?

The following spec is taken from the 2.8A 17mm driver linked above...

[TABLE="width: 332, align: left"]
[TR]
[TD="bgcolor: transparent"]

Voltage ​

[/TD]
[TD="bgcolor: transparent"]

Low​

[/TD]
[TD="bgcolor: transparent"]

Mid ​

[/TD]
[TD="bgcolor: transparent"]

High ​

[/TD]
[/TR]
[TR]
[TD="bgcolor: transparent"]

5.5V​

[/TD]
[TD="bgcolor: transparent"]

0.20A​

[/TD]
[TD="bgcolor: transparent"]

1.05A​

[/TD]
[TD="bgcolor: transparent"]

2.00A ​

[/TD]
[/TR]
[TR]
[TD="bgcolor: transparent"]

7.2V​

[/TD]
[TD="bgcolor: transparent"]

0.17A​

[/TD]
[TD="bgcolor: transparent"]

0.85A​

[/TD]
[TD="bgcolor: transparent"]

1.60A ​

[/TD]
[/TR]
[TR]
[TD="bgcolor: transparent"]

9.0V​

[/TD]
[TD="bgcolor: transparent"]

0.15A​

[/TD]
[TD="bgcolor: transparent"]

0.70A​

[/TD]
[TD="bgcolor: transparent"]

1.35A​

[/TD]
[/TR]
[TR]
[TD="bgcolor: transparent"]

11.1V​

[/TD]
[TD="bgcolor: transparent"]

0.13A​

[/TD]
[TD="bgcolor: transparent"]

0.60A​

[/TD]
[TD="bgcolor: transparent"]

1.15A​

[/TD]
[/TR]
[TR]
[TD="bgcolor: transparent"]

13.2V ​

[/TD]
[TD="bgcolor: transparent"]

0.13A​

[/TD]
[TD="bgcolor: transparent"]

0.53A​

[/TD]
[TD="bgcolor: transparent"]

1.00A​

[/TD]
[/TR]
[/TABLE]










This doesn't show anywehre near the claimed 2.8A?

And also, will i get more runtime using 2 x 26650's than using just one, even though they're in series?

 

[yazovyet]

for taking your light appart i have no idea but I would expect some glue/epoxy. maybe best to search around more on that brand/model.

those specs are tail cap measures. so 2 lions in serise is (we will say) 7.2 volts. means that on high you'd expect to draw 1.6 amps from the batteries (but then supply the LED with 2.8 amps at maybe 3.5 or 4 volts depending on the LED). I woudl expect a little lower draw if you are running an xml since the xml requires less power than a p7 (which is what i assume they tested it with)

yes you get more runtime with 2 instead of 1 battery. in theory you get close to twice as much runtime, in practice (it appears) this driver won't run on 1 battery so you would have zero runtime on one battery or on 2 batteries in parallel.

 

[Cooper_GTI]

Well im getting 1.5A at the tailcap. I assumed that this is what the led is being driven at and i would therefore gain in output by using a 3A driver. It seems i may be wrong.

 

[yazovyet]

theres a good chance you are getting in the area of 3amps to the LED then. since you have 2 lithiums (around 7.4 volts total) and the LED only needs about 3.3 volts the driver allows you to draw 1.5 amps at 7.4 volts to supply the LED with 3 amps at 3.3 volts. *these numbers are approximate but you get the idea

side note:
the keygos.com website makes me want to hit them with a shoe. it appears they claim the m13 gives 1800 lumens (with just 1 XM-L). realistically I would think you're getting around 900 lumens from the emitter (some of that is blocked by the lense and some is absorbed by the reflector but most people look at emitter lumens since you can calculate it easily).

 

[Freeze_XJ]

Don't forget that tail amps is NOT equal to LED amps if the voltage is different (ignoring driver efficiency completely). Roughly speaking power is conserved, so volts x amps should be equal. Assuming you drive your LED at 3.5V, 13.2 V x 1 A = 13.2 W, 3.5 V x 3.7 A = 13W as well, so figures might be correct (with a mediocre efficiency of the driver).

Knowing my Keygos (M10) which is driven at 2.9A at the tail (1x26650) they don't exactly lie about the current, but lumens are completely out of spec of course.
ps. Yes, with double the battery power you can either get more lumens or more runtime, since you have double the power available.