Fenix used as battery drainer

Lynx_Arc

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I was fiddling around with some near dead AAA and AA alkaline batteries
I drained dry in a dorcy and old style xnova AA 8LED and wondered if I could
get any more useful runtime out of them and popped a AA in a green LED CMG infinity and it ran it for many hours till it dimmed to nothing. After turning it off for a day it ran for perhaps 30 minutes in the light again and I go to thinking..... I wonder if the battery would even light up my fenix so I popped it in and was impressed it lit it up bright enough to be useful and for a long time also. Measuring the current at the tail was 40-50ma.
I then took a AAA that a dorcy sucked dry and stuck it into the fenix and it was even brighter.
I wonder if any other boost circuit/LED cominations work even better at very low input levels.
 

Babo

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Just replaced the AA cells in my old GPS unit this afternoon.
The batteries I pulled out had an expiration date of 2003.
Have no idea how much use they had seen, but they wouldn't
fire up the GPS.
Out of curiosity, I placed each in my Fenix....All worked fine.
I have labeled them and set them aside for use in it.
 

IsaacHayes

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Yup, it sucks cells pretty good. Just watch out for cells leaking as they like to when "dead'
 

Lynx_Arc

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I guess it makes sense somewhat that is would be a good battery drainer due to the high output from a AA to begin with. I almost bet you could run it off a single LR44 battery.
 

petery83

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The L1P is definitely a pretty good battery drainer...I'm using a nearly-dead AA battery, and it's still really bright...in fact just tonight, when I was using it in a dark bar, someone nearby asked me, "Is that a Surefire?" :thumbsup:
 

Polar_Hops

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It really DOES kill NiMH batteries. I've ruined two or three NiMH batteries sofar with it. I use a 12 hour charger, and i've had one of the batteries in there for weeks at a time, but they only last about 20 seconds =\
 

tmf2

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>It really DOES kill NiMH batteries.

So how is this happening? Is it draining the batteries too much on
rechargables as to make them unable to recharge again?


Dennis
 

Polar_Hops

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Yeah, the battery should be okay if you charge it as soon as it gets dim. I let it stay on dom the first time i got it, and forgot it was on the other times.
 

Lunal_Tic

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That's odd. I've been doing run time tests with NiMHs and have run them to nothing but they seem to be fine. I wasn't aware that you could over discharge NiMHs. I thought it was more of a unprotected Li ion problem.

-LT
 

cy

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circuit in L1-P acts simular to wayne's Mad Max and Arc LS first run. both have reputation for draining cells.
 

gadgetnerd

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I thought I read somewhere that it was OK to drain individual cells, but not cells in series. I hope that was right, since I regularly stick my used NiMHs into a custom made LED torch and run them down to "moon mode" (0.8-0.9V) with no problems.

I also read somewhere else on CPF that by the time the Fenix has started to dim appreciably, the NiMH battery is probably down to 0.9V already.
 

Xygen

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gadgetnerd said:
I thought I read somewhere that it was OK to drain individual cells, but not cells in series. I hope that was right, since I regularly stick my used NiMHs into a custom made LED torch and run them down to "moon mode" (0.8-0.9V) with no problems.

I also read somewhere else on CPF that by the time the Fenix has started to dim appreciably, the NiMH battery is probably down to 0.9V already.

If you drain 2 nimh in series, one might be below 0.9 already, without being detected. You'll never get 2 nimh with exact same capacity.

I posted this earlier: "I just discharged my first NiMh (only a 1400mAh) with my Fenix L1P. When output dropped noticeable, I took the battery out and put it in my cpu-charger to check the remaining capacity. It had 1.06V while discharging at 100mA. It had only 23.5mAh left till 0.9V.
Just wanted to tell you guys. When output drops, the NiMh is almost drained!"
 

IsaacHayes

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I used 1800mah duracells and clocked 2hr till 50% brigthness. This was on a cell that had been charged and set for a month or two. It was steady and then bam, drop to about 50%. I left it on longer than that and it got really dim, but the battery recharged fine. (I didn't care if I killed this one, the shirnk wrap is damaged anyways). I didn't check the voltage, but it was down lower than arcAAA output, but the cell came out fine...
 

Mike abcd

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Both the Energizer and Duracell sites have tech notes advising against draining NiMH below .9v due to the hit on capacity and useful cycles. Reverse voltage in a multi cell application is a lot worse though.
 

Lunal_Tic

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Just for grins I ran some Alkilines down to a glow and pulled them. I got .9V on one and .83V on the other. Mind you they were only just glowing by the time I gave up.

-LT
 

drmaxx

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I found that of the two alkaline batteries in my cordless mouse one is empty and the other one usually still has quite some juice in it. I suck them empty in one of my 1xAA lights. I imagine that this is true for most appliances with batteries in series.
 
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Mike abcd

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drmaxx said:
I found that of the two batteries in my cordless mouse one is empty and the other one usually still has quite some juice in it. I suck them empty in one of my 1xAA lights. I imagine that this is true for most appliances with batteries in series.

Not if they're matched in capacity and charged on a decent charger with individual chagring stations. Many only charge pairs in parallel.
 
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