What is inside a UPS?
or, how to turn an old UPS into an alkaline battery charger and more
I recently lost my collection of electronic components, and was looking for a cheap source of parts I could use in my projects. It turns out that my old, broken uninterruptible power supply was a goldmine of useful components! Check out the video to see what I found inside. It turns out that I had everything I needed to build a battery charger, an audio amplifier, a variable power supply and more.
The charging current = 1.25V / R
For example, I found that the 3 fuses put in series gave me a resistance of roughly 7 ohms. 1.25 / 7 = 178mA. So the battery would charge with a current of approximately 178mA.
The full datasheet for the LM317T can be found here. It contains lots of nifty example circuits. The charger circuit can be seen on page 10.