Custom UPS (Uninterruptible Power Supply)


Custom UPS (Uninterruptible Power Supply)
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Custom UPS (Uninterruptible Power Supply)

Here's the finished product! The lash-up you saw in the other photo, namely the relay switching circuit, has been placed into a nice aluminum box in the lower right, (using a double pole, double throw 12V relay.) Above it is the 13.5VDC float power supply. (It's an old linear power supply, but it works good without wasting too much power. The only drawback is the 60Hz hum, which is the loudest 60Hz you'll hear in my room when the ceiling fan is off and no music is playing.) It's connected to the inverter which has two SLA batteries tied to it. The upper SLA is the one that came out of the original APC UPS that got to the point of randomly turning off my computer. ... I blame the stupid “smart” circuits that make too many assumptions. Now I plan to use it's FETs and transformer to make an additional inverter... eventually.