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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

    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...
  3. 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...
  4. W

    Bringing back NiMh from the dead.

    1 hour in...batteries still going strong @ 5.10v.
  5. 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...
  6. 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?
  7. 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...
  8. 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...
  9. 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...
  10. 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...
  11. 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...
  12. 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.
  13. 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.
  14. 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?
  15. 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...
  16. 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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