Converting a battery only device to constant source

Thread Starter

ep327

Joined Nov 19, 2010
1
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!
 

whatsthatsmell

Joined Oct 9, 2009
102
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.
 

retched

Joined Dec 5, 2009
5,207
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
 

KMoffett

Joined Dec 19, 2007
2,918
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.

Ken
 
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