Surefire P3X Mod

Skelt11 · Jun 8, 2014

Hey guys,

I made a trade with a friend for a like new Surefire P3X Fury. Good news is the head comes off no problem so I can bore it. What I don't know is if it can run on three 18350s if I do get it bored. Any recommendations for batteries besides 18350s?

Redhat703 · Jun 8, 2014

I'm not sure about three 18350s but I know it will work fine with two 18500s.

fivemega · Jun 15, 2014

After boring stock barrel, pair of 18500 will fit nicely but if you want to run with pair of IMR 18350, you will need readily available 2x18350 barrel in custom B/S/T of this forum.

historyfuzz · Jun 15, 2014

I run two 17500s and it runs just as bright and quite a bit longer. I've read of a number of others doing the same. You also don't need to modify the light and I'm not sure why anyone would go through the trouble or expense.

Skelt11 said:
Hey guys,

I made a trade with a friend for a like new Surefire P3X Fury. Good news is the head comes off no problem so I can bore it. What I don't know is if it can run on three 18350s if I do get it bored. Any recommendations for batteries besides 18350s?

fivemega · Jun 16, 2014

historyfuzz said:
I run two 17500s and it runs just as bright and quite a bit longer. I've read of a number of others doing the same. You also don't need to modify the light and I'm not sure why anyone would go through the trouble or expense.

17500 cell has capacity of 1100 mAh and according to post #332 here current draw of P3X is way higher than allowable 2C
18500 has capacity of 1500 mAh and it's 2C (3 Amps) is closer to turbo mode of P3X also will run considerably longer.
Majority of people concern about their safety and go through trouble (if it is) and expense.
Using pair of newer protected 18650 will be absolutely safe and will run 3 times longer than 17500

cland72 · Jun 16, 2014

Even if you could run 3x18350, you wouldn't want to. The P3X is expecting 9v max, so 2x18500 would be a safer solution (to ensure you don't fry the LED), not to mention you'll get better runtime than with 3x18350.

historyfuzz · Jun 17, 2014

I fully admit that my understanding of batteries is not optimal, but on a previous CPF post, there a photo of the P3X being gauged in the 6+ amp range. Assuming that is an accurate representation of its draw, why would two protected AW 17500 3.7 V batteries be unsafe? That would seem to satisfy the light's draw ceiling and also push the light adequately. If this wasn't the case, wouldn't the protection circuit kick in anyway? I'm asking because I run these 17500's regularly in this light and I don't want to compromise on safety. Please let me know where I'm misunderstanding this.

cland72 · Jun 17, 2014

historyfuzz said:
I fully admit that my understanding of batteries is not optimal, but on a previous CPF post, there a photo of the P3X being gauged in the 6+ amp range. Assuming that is an accurate representation of its draw, why would two protected AW 17500 3.7 V batteries be unsafe? That would seem to satisfy the light's draw ceiling and also push the light adequately. If this wasn't the case, wouldn't the protection circuit kick in anyway? I'm asking because I run these 17500's regularly in this light and I don't want to compromise on safety. Please let me know where I'm misunderstanding this.

17500s have capacity of approx 1100mah. 2C is twice the capacity, but viewed as a rate of discharge. So, safe discharge rate of 2C is 2 x 1100 which equals 2.2amps. Anything over that is unsafe since it exceeds the battery's capabilities.

historyfuzz · Jun 17, 2014

cland72 said:
17500s have capacity of approx 1100mah. 2C is twice the capacity, but viewed as a rate of discharge. So, safe discharge rate of 2C is 2 x 1100 which equals 2.2amps. Anything over that is unsafe since it exceeds the battery's capabilities.

I appreciate your explanation. What could happen (worst case) with protected batteries that exceed this threshold?

historyfuzz · Jun 17, 2014

Also, I forgot to ask: Assuming current rating for 123 batteries are around 1500 mah, and there are 3 cells with an aggregate of 4.5 mah, wouldn't the 6 amp draw of the P3X still be a problem based on this equation?

cland72 · Jun 17, 2014

historyfuzz said:
I appreciate your explanation. What could happen (worst case) with protected batteries that exceed this threshold?

The protection circuit trips and the light shuts off. Or, more likely, the batteries are going to have their life span significantly decreased. I suppose absolute worst case is they violently vent (explode) in the light.

historyfuzz said:
Also, I forgot to ask: Assuming current rating for 123 batteries are around 1500 mah, and there are 3 cells with an aggregate of 4.5 mah, wouldn't the 6 amp draw of the P3X still be a problem based on this equation?

Yes, still a problem, but apparently an acceptable risk according to Surefire's assessment.

historyfuzz · Jun 18, 2014

Thank you for the information, so where can i get my P3X bored at a reasonable price?

cland72 · Jun 18, 2014

historyfuzz said:
Thank you for the information, so where can i get my P3X bored at a reasonable price?

You're welcome!

Precisionworks is the only place I'm aware of that will take the time to do it right, and get it back to you in a reasonable amount of time.

http://www.candlepowerforums.com/vb...refire®-and-other-aluminum-or-titanium-lights

historyfuzz · Jun 18, 2014

Thank you for the discussion.

cland72 said:
You're welcome!

Precisionworks is the only place I'm aware of that will take the time to do it right, and get it back to you in a reasonable amount of time.

http://www.candlepowerforums.com/vb...refire®-and-other-aluminum-or-titanium-lights

Surefire P3X Mod

Skelt11

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Redhat703

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fivemega

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historyfuzz

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fivemega

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cland72

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historyfuzz

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historyfuzz

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historyfuzz

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