Converting a battery only device to constant source

Discussion in 'The Projects Forum' started by ep327, Nov 19, 2010.

  1. ep327

    Thread Starter New Member

    Nov 19, 2010
    I am rebuilding a wireless sensor assembly which uses a lithium battery (3.6v 2.4Ah), I will be placing this inside a part which needs to be sealed. The part feeds off of 110vac, but there are virtually no 110vac to 3.6vdc power adapters small enough to fit. I calculated that the sensor uses about 5-10mA at most.

    Are there any solutions which would fit in a space about 2"x2"x1"?

    Appreciate the help!
  2. whatsthatsmell

    Active Member

    Oct 9, 2009
    Can you use a transformer outside of the sealed box plugged into the same source of the 110v? The wall wart for my rechargeable razor is 3.8v @ 80ma, although probably not regulated.
  3. retched

    AAC Fanatic!

    Dec 5, 2009
    Is there any lower voltage DC lines you can tap off of inside your device?

    If you can find a 5v line, or something close, you can whip up a little regulator to get your 3.6vDC
  4. Markd77

    Senior Member

    Sep 7, 2009
  5. KMoffett

    AAC Fanatic!

    Dec 19, 2007
    I've gutted many cellphone wall warts to get small, regulated, 100-240VAC to 5VDC switch mode power supplies. Most would easily fit your size requirements. Though most were 5VDC out, I have seen a few at ~3.6VDC. I even found a couple with name brand chips and circuits right off the data sheets. I was able to tweak their output sense voltage divider to get a different voltage. They're $0.39 to $3 at Goodwill type stores.