Help with Small Sun ZY-T13

I ordered a ZY-T13 a couple months ago and finally got around to ordering batteries for it.

It worked fine for a while but stopped working correctly after I unscrewed the head from the body.

Now it will stay on when I first start screwing the body in but when I get to a certain point it will turn off.
I’m not able to screw it all the way in.

Any ideas on how I can fix it… or what would cause it to do that?

What batteries are you using?

My guess is that the driver retaining disk got unscrewed a bit while unscrewing the body/head making the connection dodgy.

Use needle nose pliers or similar tool (lots of space, big holes) to tighten the retaining disk.


And a big welcome to bfl.

Did you remove the plastic centering ring from the light?I had this problem when the head was tightened down too much,shorts out the led + and- by touching the reflector.Try covering the terminals with electrical tape or a centering disk if you have a spare.

I’m screwing the battery holder into the driver portion when it comes on / turns off.

-Using 2600mAh 3.7v 18650s from
-I’ve tried loosing and tightening the driver retaining disk multiple times and that hasn’t worked.
-The issue started happening before I removed the plastic centering ring, I put it back on just to be safe.

Thanks for the welcome.

Try this

Unscrew the driver ring and polish both sides
Pull the driver carefully so you do not pull hard on the wires going to the led, now clean both sides of the driver on the golden outer ring, check the soldering on the wires to the led for cracks or if they are loose, resolder if necessary.
Clean insides of heatsink to remove gunk left from machining using a qtip with alcohol.
Re install driver observing proper orientation of side button
Screw back polished driver ring while pressing on driver + spring to keep it centered, tighten but not too much.
If problem persists check led solder points to the wires coming from the driver
Check for short between reflector and wires on the led