I picked up a sweet little 9 led light from HF for $5 and it was kinda flaky, shake it and the light went out, so I'd thought I'd post my improvement.
Step 1: What's the Problem
The positive connection is a spring loaded pin pushing against a blob of solder. High resistance and just poor contact.
Step 2: I Had Thought to Just Use a Mini Connector
But had none on hand. So I grabbed a 4-40 nut and tinned it up.
Step 3: Disassemble the Flashlight.
Unscrewing the ring with the hex opening let's you remove the led module. Now just solder the hex nut to the central solder pad.
Step 4: Okay
The nut makes a tight socket for the pin on the battery compartment, it also compresses the pin farther, so now no matter how hard I shake or drop it the light doesn't flake out anymore.