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ArcticMyst Security by Avery

FlexDrive V3-4 & Protected 14500s...

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Hi2all  :)

I started a thread titled April Fools over in General but I thought it might make more sense to raise the question here.



Basically one of my FlexDrive-based reds "shut off" all of a sudden, what is considered normal operations (I forgot - hence the post title, "April Fool's"  :p) So I took out the battery and measured only 0.18V with my voltmeter. I then put in a (less-than) fresh battery and a few mins later that one also dropped to 0.18V...  :eek: The batteries in question are the well-known Trustfire protected "blue-wrapped" 3.7V 900mAh 14500s.

Anyways, since the second battery was not exactly fresh, I decided to charge both of them overnight with my UltaFire 14500 charger and both read around 4.8V the next morning. I placed one in a 14500-based CREE P4 flashlight and the other in my Red and ran them both through a few duty cycles (90 on, 2-3 mins off) and then took out the batteries and measured them both at around 4.6V (the CREE having actually used up a little more).



The point of this exercise was to determine if the FlexDrive was quasi-fried and was draining the 14500 at an alarming rate, which seems not to be the case. A member however suggested that a reading of "0.18V" suggests a dead battery but as I write  this, my CREE is still going strong...

So would you say that the Flexdrives are so efficient that they can really drain a battery to that level?

Is it possible that the drive can "short out" and all of a sudden still manage to provide power to the diode but at the same time, deplete the battery at a much higher rate... ?

The laser in question is housed in a Romisen host and has a "sealed" module. Thus there is no visible spring an no visible chance of some positive section touching the case-negative host...



I'm sorry for what may be elementary questions to the DIYers but I have very little experience in this area....  :-[
Thx2all in advance  :)
 





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Sep 20, 2008
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The FlexDrive is a Boost Current Driver... it takes the Battery Voltage and
boosts it to supply the regulated current to the LD that is requested by the
driver adjustment.

As the battery's voltage drops... the Driver will demand more current from
the batteries to supply the regulated current required by the LD..

The lower the battery voltage the more the driver requests current from the
batteries... the faster the batteries deplete... :cool:

Any better informed members... please correct me if I'm wrong.. ;)


Jerry
 
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lasersbee said:
The lower the battery voltage the more the driver requests current from the batteries... the faster the batteries deplete...

Hey Jerry,

I'll buy that! The laser seems to be working normally and the battery's holding out as I run controlled duty cycles with it :)

Thx for the clarification ;)
 

drlava

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Just to add to that:

The FlexDrive V4 will only drain a battery to 2V if given the chance. Your batteries are protected so that means they will only drain to about 3.2V. HOWEVER you will not measure 3.2V after the protection has kicked in, because the protection circuit is preventing any further discharge, thus the low 0.18V reading.

The protection circuit will not allow further draining until it senses the battery has been charged past a certain point, say 3.6V. Then you will once again be able to measure it with your multimeter.

Finally, the typical max charge voltage for li-ion cells is 4.2V, due to the chemistry. If you are getting 4.8V charges, you should probably make sure that's OK with the battery.

Good questions.
 
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drlava said:
...the protection circuit is preventing any further discharge, thus the low 0.18V reading ... If you are getting 4.8V charges, you should probably make sure that's OK with the battery.

Hi & thx very much for enlightening us - that info clarifies everything  :D

As for the batteries, all my rechargables, be it these 14500s or the CR123As I use with my Daguin's DJR set or with my "Jaynom", are all from DX and are charged by a DX charger (both quite popular with the community, afaik; hyperlinks are in the OP).

Of course I would love to get confirmation from another owner of said batteries & charger that they also get 4.5-4.8V readings after fully charrging said batteries...  :-/
 




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