I got tired of replacing the SLA batteries in mu UPS every couple of years, so I switched out the SLA cells for LFP cells. Wanted more back up time so I added an XT-60 connector to add an external battery. I also added a small 14.6 volt charger (plugged into the grid outlet) to fully top off the batteries when the grid is on.
I also repurposed some 50 Ah LFP cells and made a larger external battery. I plan to attach that to the UPS that runs my network devices.
