PA-28 pilot reported cascading systems failures was traced to loss of electrical power. The pilot diverted and made a precautionary landing.

Narrative

Took off from ZZZ1 to head home to ZZZ. About 25 minutes into flight noticed the GPS flicker. The GPS flickered a few more times before going completely out 30 seconds later. The comms also went out and the EFI indicated external battery disconnected. Immediately; diverted to nearby airfield and landed without any issue. Investigated the engine bay and found no sign of visible signs of electrical failure (burnt wires; broken alternator belt; etc). The aircraft did not have enough battery strength to turn the engine over once on the ground. I called the owner of the aircraft who arranged a Maintenance team to help get the plane started. I called ATC at my home airport and let them know that I'd be arriving with no radio. I embarked and made it to my home airport and was guided in with the light gun and ultimately ended in an uneventful landing. The aircraft is in Maintenance now investigating the cause of the electrical failure. I believe an Alternator failure is the root cause of this failure. Looking back; I wish that I would have went with my gut when I checked the ammeter and it did not respond how I would expect. I chalked it up to the LEDs not having much current draw and not showing much on the meter. Additionally; I was under the impression that the Ammeter would indicate a negative current if the alternator was not supplying electricity and the battery was discharging. I plan to review this airplanes systems more in depth. Also; looking back I am not proud that I took off once landing. That was poor ADM fueled by get-there-itis. I plan to spend sometime reviewing how to deal with external pressures of flying. This was my first situation of this type.