My 2 cents on Running a Convoy M21F Without a Battery

Flashlight Modding and DIY Parts
1

This is by request for someone who wanted to run a convoy M21F on USB without a battery.

The problem with running straight from USB is that it will only run at a very low setting, and draws about 0.2 Amps from the USB. I found that by adding a capacitor in place of the battery it will run at almost 2 amps direct from the USB.

Here is how I did it.

I used a 3d printed adapter, 2 pennies, and a capacitor salvaged from an old circuit board I had laying around.

The positive side of the capacitor is treated as the positive side of the battery.

With the adapter installed it will draw almost 2 amps continuously from the USB.

Hope this helps somebody!

STL files to print can be found at:

https://www.thingiverse.com/thing:5389334

2

What a cool project! Thank you for sharing!

3

Thank you so much for figuring out a way to get this super useful functionality on the M21F, and for sharing it.

With your mod, the M21F can essentially become a light fixture (via ceiling bounce) without the worry of a lithium battery inside overheating.

One might ask, don’t you have lights in your house? Well, not in 1700K with CRI 100 (just use Lee Zircon 802 on the GT-FC40 1800K).

Thank you once more for your mod!

4

Very good project!
With a high capacity powerbank M21F can works for hours on 10% power stage which give very useful power of light.

5

This idea seems nice with normal caps, but I would personally not do it this way.

However, this is a good idea to do with 2 supercaps in series as that way, you’ll get a lot more capacity.

6

Might I ask why not?

And what does capacity have to do with it?

7

What often happens with this kind of light basically is that I need to take it out for more precise usage, and the capacitor will be discharged very quickly.

A supercap by comparison will have a lot more capacity, and should allow portable use for a short while.

8

Oh, I thought you meant there was something wrong with it electronically.

All I wanted was to turn it into a 2000k usb desk lamp, and the basic capacitor works for that.

It won’t even turn on without the usb power with this small of a capacitor.

Discharger had asked in the convoy thread if you could run it without a battery. It will but only at 0.2 Amps. My goal was to find a way to get the full 2 amp charging current to power the led without a battery.