2x18650 direct drive P7 mods: current?

[GarageBoy]

What is the current a P7 sees while driven by 2x18650s? Wondering if its worth it to get a regulator

 

[JohnF]

I'm no expert, but:

2 x 18650's in parallel could work direct drive without even a series resistor if the vf of the emitter was on the high side. With the batteries in series, you'd generate a bit of heat from a current limiting resistor, so a driver like the hipCC from 'taskled.com' would be more efficient.

John F

 

[GarageBoy]

I was going to use a Shark, but if it's around 3A, I may go DD

 

[Lumencraft (Matt)]

I am going to assume that you are wanting to use 2x18650s in parallel, because your led DD on 2x 18650s would not last a full second.

On 2x freshly charged 18650s in parallel you would probably see about 3.4A and then the current should drop to around 2.8-3.0 amp for the better part of the cycle.

If you are wanting to use the 2 cells in series DD an MCE wired 2S 2P would work. There are a couple of trick that can be done with a cheap 2$ 7135 driver that would give around 3 amp and you would also have reverse polarity protection. If you decide this is something you are interested in I will elaborate.

 

[GarageBoy]

TOTAL brain fart on my part...I thought it was like the Lux V where the Vf was 7-8V....

 

[CampingLED]

Vf on the P7 is as follows:

H 3 - 3.25V
I 3.25 - 3.5V
J 3.5 - 3.75V
K 3.75 - 4V

I and J are the most commonly available ones. You can still take a chance to DD drive with 18650 in parallel for J bin, but for I it is better to use a regulator.