Pilot reported generator failure inflight while possibly penetrating Mode C veil without operating ADS-B.

Narrative

While flying from Casa Grande Airport to ZZZ in my Cessna 150F I experienced a generator warning light. The light appeared intermittently at first and I attempted to adjust my RPM in the hopes of greater generator output. At a certain point the Generator warning light went solid. At this point I was flying on battery power alone. I fly with a stratus ADSB IN and have a backup handheld radio. I made the decision to turn around and return to Casa Grande Airport. At this point I was in vicinity of ZZZ1. At some point the generator warning light went out as well as my fuel indication. At this point my battery was completely dead. As a result it is possible that I was within the Mode C/ADSB 30NM veil of KPHX; but since my battery was dead I was no longer broadcasting either source of information. I would like to highlight I was not within the Class B airspace; only the veil. I continued to Casa Grande uneventfully; monitoring traffic on foreflight and making position calls via my handheld radio. I am working with my A&P to diagnose and fix the mechanical issue before flying within the veil again.