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  1. W

    Lithium ion "C"?

    Lithium ion \"C\"? Is there such a thing as a "C" size lithium ion cell?
  2. W

    Pick-a-number for a free Arc AA or 2 other prizes!

    Re: Pick-a-number for a free Arc AA or 2 other pri 19
  3. W

    Are certain colors of LEDs more efficient?

    Just wondering, are certain colors of LEDs more efficient than others? Does one offer more lumens per watt? If so which color is the most efficient?
  4. W

    O-sinks - what mods necessary?

    I'm hoping to order an o-sink whenever they're available for the D cell mags. Is the only mod necessary of the mag to cut down the reflector? What exactly needs to be done to it? Also, is there room inside my 3D to put a 5 watt resistor, without modifying the switch?
  5. W

    Bringing back NiMh from the dead.

    I charged the batteries today for about 4.5 hours @ 400ma. Let them rest for a little while. Then hooked up a constant current 200ma load. Got to 1000mah and 3 of the batteries were still at 1.19v. The 4th battery was down to .15v. Fortuneately I only need 3, so I'll test those 3 by themselves...
  6. W

    Bringing back NiMh from the dead.

    While we're talking about it, what is the standard procedure for finding the capacity of AA's? How much load to what voltage? I would like to get the exact capacity after a few cycles...
  7. W

    Bringing back NiMh from the dead.

    1 hour in...batteries still going strong @ 5.10v.
  8. W

    Bringing back NiMh from the dead.

    Well, after 7 hours at C/6, the batteries are at 1.46v. I hooked up a Mag lite bulb, and it's burning nice and bright @ 700ma. We'll see how long it lasts...
  9. W

    Bringing back NiMh from the dead.

    [ QUOTE ] gwbaltzell said: I would suggest 4 cells and a 51 ohm resistor. [/ QUOTE ] Why 4 over 3? Will 4 with a bigger resistor give me more run time?
  10. W

    Bringing back NiMh from the dead.

    Well, after an hour at 200ma,(C/6) the batteries all are 1.4v. I'll keep charging them for a little while and see what happens...
  11. W

    Bringing back NiMh from the dead.

    Yes, I know NiMh are cheap, but so am I. Yes, they are so low simply because of self discharge, I know the pack was working fine when I last used it a year or two ago. I want to take 3 of the batteries, put them in a short section of PVC pipe, slap on a white LED, and viola! A cheap, almost...
  12. W

    Bringing back NiMh from the dead.

    I have battery pack with 8 NiMh AA batteries that has been laying around for quite a while. It's only 1200mah, so obviously it is pretty old. It's been sitting so long all the batteries read 0.00v. I want to try and charge it up. What's the best way to do it? Would it be better to seperate them...
  13. W

    Constant current NiMh charging

    [ QUOTE ] gwbaltzell said: There are chips made for rapid (3-4 hr) charging. [/ QUOTE ] Are there any as easy to use as the LM317? What would be a good rate to charge them at if they aren't totally discharged? (As in, getting overcharged for a few hours) I'm thinknig I could make two...
  14. W

    Constant current NiMh charging

    I'm building a light that will use a 6AA NiMh batteries in series. I want to be able to charge the batteries without taking them out of the light, so I will need to make my own charger. I'm thinking simple constant current - something like an LM317. First question: Can I do that? Just simply...
  15. W

    Easy way to boost voltage?

    I'm trying to boost the output of the power supply, not the power supply itself. There's no easy way to do that? I guess I could modify the supply, how might I do that? It's just an old 250 watt AT computer power supply.
  16. W

    Easy way to boost voltage?

    I have a power supply that is putting out about 11.5v @ 9 amps. I need about 14v @ 2 amps. Is there an easy way for me to get this? Maybe just a coil of wire or something? It doesn't need to be efficient, or small. Only easy.
  17. W

    Cell phone light...6 volts ok??

    [ QUOTE ] fivemega said: I think, it will work fine. 4.8 volt is nominal voltage and could be more under charge while phone is on use. [/ QUOTE ] I thought about that...but the 6v for lithium batteries is also nominal. I think I'll just go with 1 diode in series...that's about .7v drop right?
  18. W

    Cell phone light...6 volts ok??

    I've got an old cell phone with no service that I'm going to install a luxeon on. Why? It will be a GREAT emergency light...as 911 still works on the cell phone. Anyway, the battery on this phone is dead. I ripped it open, and inside was simply 4 NiMh AA batteries. I would like to replace them...
  19. W

    Easy step up circuits

    Hello everyone. I recently purchased a couple of those solar yard lights to play with. They come with 2 nicad batteries and a pathetic amber LED. I want to put some white LEDs in them. Can anybody point me in the direction of some schematics for a circuit that will boost the 2.4 volts to the...

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