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How can I make a fake cellphone battery?

Doug3004

Sep 5, 2014
119
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Sep 5, 2014
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119
I have an old cellphone, one running Windows Mobile.
I haven't used it as a phone in many years, but I took to using it as a bedside alarm clock because of the options that the alarm clock feature has. I keep it plugged in and at home all the time now.

A few days ago I noticed that the back cover of the phone was bulging a bit and wouldn't close. Taking a closer look I found that this was because the battery was starting to bulge out. It's about ten years old (and I used it as a phone for the first four years) so that's not real surprising.

There's replacement batteries available, but they cost $25 but they look like fakes (they look shoddy and not as nice as the OEM Samsung batteries) and people say they don't last nearly as long as the original ones did (-they don't provide nearly as much run time, nor do they last nearly as many recharging cycles-). And I don't really need it to be portable anyway, as it can stay plugged into the wall... But it won't power up without a battery in it.

How can I trick it into thinking there's a battery when there's not? The battery measures about 42mm x 62mm x 6mm thick, so there is room to stick a little PCB in there. The battery has four contacts to it; is it just as simple as shorting across the two pairs of leads?
 

kellys_eye

Jun 25, 2010
6,514
Joined
Jun 25, 2010
Messages
6,514
Fitting an external power adapter should be straightforward providing you can 'fool' the phone battery maintenance circuitry. Some batteries have internal circuitry whilst others are 'dumb' but they nearly all have temperature monitoring which may have to be bypassed.

Post a picture of the side of the battery where the contacts are visible.
 

Electrobrains

Jan 2, 2012
259
Joined
Jan 2, 2012
Messages
259
Easiest way:
Use the old battery!

1. Carefully remove the PCB with the gold plated pads, including whatever circuitry is there (thermistor, charging regulator etc)

2. Cut away the old, bad Li-cell (or leave it disconnected as "space-filler").

3. In it's place, attach an external voltage source (same voltage/polarity as the original battery, eg. 3.6V) to the tabs where the Li-cell was.

4. Mount the "mini-battery" in a good way (eg. hot glue).

DISCLAIMER:
Anyone using this idea is totally responsible for the results!
Be aware of possible damage of material, risk of fire, danger of manipulating a Li-cell, loss of warranty etc.
 
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