I recently burchased a Trustfire F3 with 3 Q5s, I would like to increase it’s output. On opening the pill I noticed that it has a 19mm battery contact board and a 16.7mm freely floating driver board that is wrapped in a lot of heat resistant tape. The smaller board is the driver and contains a controller, 2 AO8T mosfets and some support resistors and capacitors.
I have tried replacing the driver with an 8*AMC7135 380 bin driver and while it works well with Samsung 18650 2600mAh unprotected cells, output current rapidly decreases whenever I use Panasonic CGR18650CH hybrid batteries. It’s a pity because even with an initial 3.04A drive current, the Panasonic’s battery voltage is still close to 3.7V throughout which should be enough to drive the emitters to 1.3-1.4A each. Note that I tested the emitter’s V-I characteristics. This should be more than addequate to drive the LEDs After a little more than 1-2 minutes the output current starts dropping to around 0.9A.
It seems that the Samsung cell voltage drops enough to keep the AMC7135s within it’s operating range but that the Panasonic hybrids excess voltage is heating them enough to initiate current foldbback.
My question is this: Would it be better to just add another A08T mosfet in parallel with the 2 existing ones oruse an IRF 7133 SOIC 6A mosfet. I was was also thinking of using a copper/aluminum pipe to heatsink and pot the AMC7135 board with silicon grease. Do you think this would be better as it affords regulation with IMR/Hybbrid batteries?
The challenge is to get 700-800 lumens output from a single battery operated light. Runtime isn’t important to me and besides I have the option of low mode.
Thank you in advance for your suggestions.