Has anybody ever dropped a Convoy S 11 on the ground and broken it ?
I have broken several Convoy S 2s by dropping them only 3-4 feet.
What breaks inside and how do I fix it ?
Sometimes the springs that touch the battery collapse from being dropped. And the battery cant make contact. Try putting a screwdriver from the - of the battery to the body of the flashlight. And see if it turns on. Streching the spring would fix it until the next drop
Also the switch could break internally (not likely but can happen). Test the same way. Battery - to body of flashlight.
Option 3 is some solder joint broke somewhere, and you might get lucky and be able to resolder the joint. It should be viewable (lifted from driver, or led pcb).
Also if the battery is protected, the fall could have damaged the circuit board on the battery. Swap with a known good battery (or test voltage if you have a volt meter).
There are other ways a flashlight could break, but these are what came to mind first.
3 questions:
a) When you mean “broken” what do you mean? It stops working? Does physically break in some way?
b) They are modded or stock flashlights?
c) Where did you bought them: from Convoy (Simon) or other store/seller?
Sometimes what happens is that it doesn’t break but it gets loose in someway. Other times, impact may cause some damage on components or provoke “shorts”
Some suggestions:
a) try to see if the retaining ring in the tailcap is loose or tightened, and if so, adjust it/screw it tight.
b) check the same thing with the retaining ring and/or the pill in the head. And the battery tube too, check if all the contacts are being made.
c) unscrew only the tailcap, leave the battery in and, using a conductive wire/pair of scissors/ tweezers, try to make it work by placing 1 contact in the battery negative and 1 contact in the non-anodized part of the tube. This will help you understand if the problem is on the tail or on the head.
d) if after doing this the flashlight doesn’t work, try to unscrew the pill, check if there is any contact between the reflector and the wires/solder on the Led PCB, as they may be some kind of short.
e) if nothing of this works, maybe it is a driver problem :zipper_mouth_face:
Hope it helps. 
Good advice MascaratumB! I can’t think of anything else to try. It seems it should be a mechanical problem, like a retainer ring not tight enough, since the driver and LED should withstand a lot of impact.
When I say it broke, I mean it stopped working. I only dropped it 4 feet. They are stock Convoy s2+ lights with steel buttons purchased from Banggood.
I gave one to s friend and he found that a trace on the driver had cracked. He soldered a wire on to bridge the gap. I’ve had 3 or 4 of these stop working after one drop. My Jaxman triples keep working no matter how many times I drop them.
I recently bought a Convoy s11 with xhp50 and it’s a superb light.
Are there any s2 size 18650 lights with xhp leds ?