Uninterruptible Power Supply

This is my UPS for my home server, networking and surveillance equipment. I built this from an APC 1500va UPS I found online and installed my own (significantly larger) batteries - they're bigger than the UPS itself!

Due to the larger batteries, the UPS had to be calibrated to expect the longer charge and draining runtime. This was surprisingly easy to do, and I just plugged them using some thick cables, an Anderson connector (the same as the UPS uses) and a reasonably large inline fuse.

The batteries are 12v each and are connected in series to create the 24v the UPS expects.

A large, constant load (the lamps) was connected to the UPS via a modified power splitter/extension lead (seen below - to connect to the female C13 connectors) which drained the batteries until they were entirely empty. They were then left to charge fully, and the calibration of the UPS for the larger was complete.

The stock batteries the UPS came with were a combined 17.0Ah and I replaced them with two Yuasa SWL2500EFR batteries that are 90.0Ah each. These are specific batteries designed for use in a UPS and to be sat fully charged for very long periods of time, as well as delivering massive amounts of current when required (rated for up to 2500w each).