Protected cell voltage

[qwertyydude]

Does the cell protection mechanism in 18650 cells drop any significant amount of voltage output as in adding internal resistance to the cell? If so would this affect the brightness of a direct drive P7 light since these draw upwards of 3 amps?

 

[Meterman]

Don't worry . . .

If the switch in your flashlight has only 50mΩ, voltage drop across it will be about double the amount of that across the PCB.

Taken a TrustFire protected 18650 I have just measured for you:

11.6mV @ 0.5A
23.6mV @ 1.0A
48.4mV @ 2.0A
74.6mV @ 3.0A

voltage loss across the PCB.

Wulf

 

[jirik_cz]

Interesting, thanks. Did you measure gray trustfire with short circuit protection or blue trustfire without this feature?

 

[Meterman]

I had measured the grey one with short circuit protection.

Wulf