Klarus        
Results 1 to 5 of 5

Thread: 9v PP3 keychain pocket rocket?

  1. #1
    Flashaholic MikeHunt79's Avatar
    Join Date
    Nov 2005
    Location
    Bristol, UK
    Posts
    171

    Default 9v PP3 keychain pocket rocket?

    Ok, I'm planning to build this from scratch. How about this for a keychain light for occasional / emergency use?

    9v pp3 (probably alkaline, maybe NiMh) battery, direct driving a lux V at around 900mA, with a resistor. I already have the Lux V and it has a Vf of around 7v. It won't be very efficient, but runtime is not really an issue for me with this light... Size is the main concern.

    I was thinking a 20mm colimator would be best... probably a 2 degree carclo one... I've already got a machined MiniMag head I can fit this in.

    Would a Alkaline be capable of outputting high current needed, or would a NiMh be a better option here? Also, I'm guessing I'd need resistors with higher current than normal current ratings.

    Also, where can I get metal (preferably alu) PP3 holders? I was hoping to make it act as a heatsink as the Lux V's get hot.

  2. #2
    Flashaholic* Planterz's Avatar
    Join Date
    Dec 2005
    Location
    Tucson, AZ
    Posts
    1,162

    Default Re: 9v PP3 keychain pocket rocket?

    I can't help you with all the technical stuff, other than to say that if this light is for emergency/ocassional use, go with lithium batteries. Alkalines will eventually self-discharge, can leak, can't drive much juice and don't work well when cold. NiMH self-discharge even faster than alkalines. Lithiums however can drive current hard, have a 10+ year shelf life, and work fine when cold. NiMHs should work fine for regular use, but don't rely on them for emergencies.

  3. #3
    Flashaholic MikeHunt79's Avatar
    Join Date
    Nov 2005
    Location
    Bristol, UK
    Posts
    171

    Default Re: 9v PP3 keychain pocket rocket?

    Ok, thanks... I've managed to get quite a good deal on some "Ultralife" PP3 lithium batteries, so I ordered 20. I didn't see a max current rating on the site, so I hope they will cope. Do lithiums batteries drop voltage as they are used like lithiums or do they hold thier voltage like NiMh's?

    Now, I just gotta figure out where to get a holder, and work out what resistors I'm gonna use.

  4. #4
    Flashaholic* offroadcmpr's Avatar
    Join Date
    Feb 2005
    Location
    CA
    Posts
    805

    Default Re: 9v PP3 keychain pocket rocket?

    Quote Originally Posted by MikeHunt79
    Ok, thanks... I've managed to get quite a good deal on some "Ultralife" PP3 lithium batteries, so I ordered 20. I didn't see a max current rating on the site, so I hope they will cope. Do lithiums batteries drop voltage as they are used like lithiums or do they hold thier voltage like NiMh's?

    Now, I just gotta figure out where to get a holder, and work out what resistors I'm gonna use.
    there is some voltage drop, more than a nimh, but less than a alkaline.

  5. #5
    Flashaholic MikeHunt79's Avatar
    Join Date
    Nov 2005
    Location
    Bristol, UK
    Posts
    171

    Default Re: 9v PP3 keychain pocket rocket?

    Quote Originally Posted by offroadcmpr
    there is some voltage drop, more than a nimh, but less than a alkaline.
    Any guesses on how much drop would there be roughly at 700ma draw? As long as it doesn't go below 6v I should be ok.

    If theres too much drop, I could always use NiMh but I'd have to always keep the battery charged.

    Also, I reackon I might be able to modify an existing 1xAA torch body to accomidate a pp3.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •