A Little Confused About P7 Lights, 18650 & Voltage Requirements

Liquidspaceman · Apr 24, 2009

I had been checking out the DX style P7 lights with the 1x18650 configuration and it seems like most of the P7's I saw had a maximum voltage of 4.2 volts... hence using the single 18650 seemed like the only option.

For a little backstory, how this started was that I wanted a P7 that could use 2 x CR123 primaries. That's when I ran into the 18650 wall.

Then I saw the Solarforce L900. 1 P7 with 3x18650 cells. This may be a really dumb question, but how is that possible? Wouldn't the 3 18650 cells voltage blow the P7 that is only rated at 4.2 volts? Obviously there must be some type of regulation I am missing out on, but help me out with what I'm missing or not understanding?

The reason the Solarforce L900 is bothering me the most though, if it can run 3 18650's, why not 2 or 3 cr123 primaries?

I'm just really trying to stay away from 18650's.

bigchelis · Apr 24, 2009

Liquidspaceman said:
I had been checking out the DX style P7 lights with the 1x18650 configuration and it seems like most of the P7's I saw had a maximum voltage of 4.2 volts... hence using the single 18650 seemed like the only option.

For a little backstory, how this started was that I wanted a P7 that could use 2 x CR123 primaries. That's when I ran into the 18650 wall.

Then I saw the Solarforce L900. 1 P7 with 3x18650 cells. This may be a really dumb question, but how is that possible? Wouldn't the 3 18650 cells voltage blow the P7 that is only rated at 4.2 volts? Obviously there must be some type of regulation I am missing out on, but help me out with what I'm missing or not understanding?

The reason the Solarforce L900 is bothering me the most though, if it can run 3 18650's, why not 2 or 3 cr123 primaries?

I'm just really trying to stay away from 18650's.

The P7 can be made to run on multiple voltage. The cheaper variants like the DX or KD will not have this flexibility. If you want a P60 drop-in that will run from 3 to 6 volts look at the custom section. Nailbender sells them for $65 delivered. I used mine with 2 primaries and when MrGman tested the drop-in made 450 lumens out the front.

The L900M that uses 2 18650's is just amazing. The throw of an R2 with the spill of a P7. The only downside is its kinda big to carry around, but impressive none the less.

Mjolnir · Apr 24, 2009

Why do you want to stay away from 18650's? They are much more cost effective than cr123's if you plan on actually using the light.

bigchelis · Apr 24, 2009

Mjolnir said:
Why do you want to stay away from 18650's? They are much more cost effective than cr123's if you plan on actually using the light.

+1
Ever since I discovered the 18650 for my Surefire 6P's I want to make them all 18650 compatible. Currently my 6P stock is being bored to accept the 18650 IMR cells.:thumbsup:

I do like the multiple voltage capabilities too. If you want 6v~13v drop-in with MC-E LED: look at Malkoff Devices MC-E P60 drop-in. You can run up to 3 rechargeables, regardless of the size. My personal favorate is 2 18650 set-up with a Solarforce or Surefire 6P hosts.

Liquidspaceman · Apr 24, 2009

Thanks for the replies. Wasn't interested in 18650 because I wanted to keep my lights standardized as much as possible with either AA or CR123. I seem to have no way to avoid the 18650... however... maybe it's going to have to be the only way to go.

Mjolnir · Apr 24, 2009

Trust me, rechargeables make you feel much less guilty. You can turn your light on and off whenever you want, for no good reason, without worrying about having to buy new batteries for every few hours of usage.
Even thought you can get CR123's in stores, most of the time they are $12+ a pair, which isn't really worth it at all. Most people order them online; if you are going to order online anyways then you might as well get rechargeables.

Lighthouse one · Apr 24, 2009

You really don't want to run a P7 on rcr123 batteries. Too much power draw. That's why we use 18650 batteries. One will power a P7 just fine. I have the P7D 5 mode, and the light is plenty bright, but the larger models with 2 18650's will provide a longer run time, and possibly a longer throw...depends on the reflector design and size.

Pontiaker · Apr 24, 2009

I have a few of the different DX P7 cheapie lights made for the single 18650, one is the MTE, and I run primary 123's in them almost excusively. They work fine, are very bright and dont seem to run any hotter than with the 18650.
Matt

A Little Confused About P7 Lights, 18650 & Voltage Requirements

Liquidspaceman

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bigchelis

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Mjolnir

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bigchelis

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Liquidspaceman

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Mjolnir

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Lighthouse one

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