Surefire E2D Ultra Battery Options

Chris_Himself

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May 22, 2011
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Alright I'm back after like a decade of inactivity

Someone gifted me their old 1000/15 lumen E2D Ultra LED I have CR123 primaries for emergencies in the car

I wanted to do the "correct" thing so I bought 4 Surefire Lifepo4's and they run the light well but the dinky 450mah capacity leaves me wanting. I can't seem to find a concrete answer I know 16650's WORK at 4.2v to the eventual 3.7, but with the stock SF driver will it see the 3.7 nominal voltage and boost current to give me full output for the entire runtime til the batteries LV cutoff or will I get dimmer output down to an eventual LV cutoff from the light side? I don't know anything at ALL about these LED Surefire drivers. In the past I was just goin HAM on the P60 circuit, full Oveready host, Cryos bezel, etc.. take me back lol.

I looked at the Lumensfactory stuff and I eventually just end up spending $140 on a completely brand new light in parts which is FINE, but I mean I have nice Laulimas so the triples don't make sense, and I'm fairly impressed with the hostile TIR searing white hot beam of the stock KED2-A

The switch also sucks (not always reliable about switching modes, I remember this being a problem in the past) so I dunno if its a crime to tear apart stock SF tailcaps these days for the McClicky or I should just buy an LF tailcap with one built in.
 

vicv

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Well the "correct" thing is to run cr123s in it😉. Are the lfp cells actually leaving you wanting or you just don't care for the number? Otherwise I know we all like to tinker but the light is designed for cr123s. This is a backup light, not an edc. So $5 a year for cells should not be too difficult, imo
 
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desert.snake

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Alright I'm back after like a decade of inactivity

Someone gifted me their old 1000/15 lumen E2D Ultra LED I have CR123 primaries for emergencies in the car

I wanted to do the "correct" thing so I bought 4 Surefire Lifepo4's and they run the light well but the dinky 450mah capacity leaves me wanting. I can't seem to find a concrete answer I know 16650's WORK at 4.2v to the eventual 3.7, but with the stock SF driver will it see the 3.7 nominal voltage and boost current to give me full output for the entire runtime til the batteries LV cutoff or will I get dimmer output down to an eventual LV cutoff from the light side? I don't know anything at ALL about these LED Surefire drivers. In the past I was just goin HAM on the P60 circuit, full Oveready host, Cryos bezel, etc.. take me back lol.

I looked at the Lumensfactory stuff and I eventually just end up spending $140 on a completely brand new light in parts which is FINE, but I mean I have nice Laulimas so the triples don't make sense, and I'm fairly impressed with the hostile TIR searing white hot beam of the stock KED2-A

The switch also sucks (not always reliable about switching modes, I remember this being a problem in the past) so I dunno if its a crime to tear apart stock SF tailcaps these days for the McClicky or I should just buy an LF tailcap with one built in.
The version with 1000/5 lm at 16650 works dimly, the old 500 lm version works brightly at 16650, but there was a 600 lm version, which looks no different from the 500 lm version, it also worked dimly at 16650 in strong mode
 

Chris_Himself

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May 22, 2011
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The version with 1000/5 lm at 16650 works dimly, the old 500 lm version works brightly at 16650, but there was a 600 lm version, which looks no different from the 500 lm version, it also worked dimly at 16650 in strong mode
do you know how much dimmer? im willing to live with like HALF the output tbh

Those fivemega 18650 bodies might be the solution im looking for
 

Sean

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I've always been happy with Surefire Lifepo4's. Sure they don't last as long but I've had mine for years without fail. Just carry your extra set if your worried about battery life. You may be in necessarily be worried about the capacity of Surefires Lifepo4's.
 

vicv

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I've always been happy with Surefire Lifepo4's. Sure they don't last as long but I've had mine for years without fail. Just carry your extra set if your worried about battery life. You may be in necessarily be worried about the capacity of Surefires Lifepo4's.
Ya I have one set and I keep some primaries in an sc2 if need be. Hardly ever do though
 

Whistler24

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In my ultra, I used two vapcell t8's (16340), they ran just fan with full output, way better run times than the rechargables surefire offers, run times are closer to the 123 primaries.

Surefire doesn't recommended, but the guy I spoke with at surefire said "the marketing team doesn't want us to say it works with the 16340's but they work just fine with just slightly less runtimes than the primaries"
 

rrego

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In my ultra, I used two vapcell t8's (16340), they ran just fan with full output, way better run times than the rechargables surefire offers, run times are closer to the 123 primaries.

Surefire doesn't recommended, but the guy I spoke with at surefire said "the marketing team doesn't want us to say it works with the 16340's but they work just fine with just slightly less runtimes than the primaries"
Damn, Surefire rep owning up to the compatibility with 16340s. Cool. When was this info provided?
 

rrego

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Alright I'm back after like a decade of inactivity

Someone gifted me their old 1000/15 lumen E2D Ultra LED I have CR123 primaries for emergencies in the car

I wanted to do the "correct" thing so I bought 4 Surefire Lifepo4's and they run the light well but the dinky 450mah capacity leaves me wanting. I can't seem to find a concrete answer I know 16650's WORK at 4.2v to the eventual 3.7, but with the stock SF driver will it see the 3.7 nominal voltage and boost current to give me full output for the entire runtime til the batteries LV cutoff or will I get dimmer output down to an eventual LV cutoff from the light side? I don't know anything at ALL about these LED Surefire drivers. In the past I was just goin HAM on the P60 circuit, full Oveready host, Cryos bezel, etc.. take me back lol.

I looked at the Lumensfactory stuff and I eventually just end up spending $140 on a completely brand new light in parts which is FINE, but I mean I have nice Laulimas so the triples don't make sense, and I'm fairly impressed with the hostile TIR searing white hot beam of the stock KED2-A

The switch also sucks (not always reliable about switching modes, I remember this being a problem in the past) so I dunno if its a crime to tear apart stock SF tailcaps these days for the McClicky or I should just buy an LF tailcap with one built in.
I had the same issue with my P2X Fury Intellibeam.

I picked it up from eB thinking it would work well with 16650s, but it sucked and flickered due the voltage.

I chanced it and purchased KeepPower RCR123 that put out 3 volts. The batteries are oversized, but to my surprise they work in the Fury Intellibeam (runs at full output). However, they do not work on any of my other Surefire LED lights. I ended up buying a second set.

I did a rough runtime test and got 40 minutes at full 600 lumen output before the protection kicked in.

Good luck on your battery search for the Defender Ultra.
 

Chris_Himself

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May 22, 2011
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I forgot Malkoff MDC's are basically E2's so I already had the answer to this for YEARS
I have the definitive answer in case anybody is wondering.

It runs about 800+ lumens based on my well trained eyeball hot off the charger at 4.2 on direct drive which continues to dim until the battery cutoff at 2.5v. The runtime is around 1.5-2 hours depending on if you have a tolerance for it dimming or not. LifePo4's run brighter but they're finicky to manually switch to that mode on whatever charger you're using thats compatible.

I think the "fix" is just to buy a Malkoff MDC body, 18650 3200mah all day and call it done. Keep primaries for backup/outdoors use since you don't want to leave your batteries depleted during a trip. Or you know, just buy a Surefire MDC 18650 and call it done for less money and have something superior.
 

BattleBrat

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Feb 12, 2020
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I have been using the Surefire rechargeables in my E2D Ultra 1000/15 for a year and no issues other than I had foolishly not selected Lithium iron phosphate on the charger when charging them and shortened their life. Gonna get two sets and the Surefire charger next to avoid shenanigans. Looking at the Stiletto Pro II as a possible upgrade in the not distant future (I've had the E2D for 3 years)
 

vicv

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I have been using the Surefire rechargeables in my E2D Ultra 1000/15 for a year and no issues other than I had foolishly not selected Lithium iron phosphate on the charger when charging them and shortened their life. Gonna get two sets and the Surefire charger next to avoid shenanigans. Looking at the Stiletto Pro II as a possible upgrade in the not distant future (I've had the E2D for 3 years)
They're very robust. I don't imagine you hurt them
 

aznsx

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They're very robust. I don't imagine you hurt them
I got stupid and overcharged 2 in a VP2 to 4.2 without checkng the switch one day. DA. Anyway, I kept waiting / hoping they would eventually 'settle' to near their normal characteristic voltage, but they didn't. I think they stayed up around 3.6+. Probably just over-cautious on my part, but I taped the ends and put 'em in the outgoing / hazwaste bin. I didn't want strange cells of unknown disposition mixing in with the general population, and that was the best way for me to get over my DA move, learn from it, and move on without need for concern.
 

vicv

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I got stupid and overcharged 2 in a VP2 to 4.2 without checkng the switch one day. DA. Anyway, I kept waiting / hoping they would eventually 'settle' to near their normal characteristic voltage, but they didn't. I think they stayed up around 3.6+. Probably just over-cautious on my part, but I taped the ends and put 'em in the outgoing / hazwaste bin. I didn't want strange cells of unknown disposition mixing in with the general population, and that was the best way for me to get over my DA move, learn from it, and move on without need for concern.
Fair. But I've charged them many times to 4.2v. They always step down to ~3.3v after a few minutes. I wonder why yours didn't. I'm not saying to charge them to 4.2v, but it's always been accepted that they could be safely, just may lose some long term cycle life
 
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