Charging system/headlights

Charging system lights (parking brake and battery) came on upon start one day back at the first of the year. (It was still cold out.) I took it to local AutoZone and they tested it. Said alternator and battery bad. Replaced both. Rest of that day the lights were out and I assumed was fixed. The next day I start my car and they are back on. When I hit 900 RPM they went out. Still to this day the same point they go out. So when started, low voltage readings. When hit the 900 mark they are normal. However, when driving or just sitting, I get random spikes where I’ll be running a high voltage over 14.8. My fan speed goes higher than the setting, even if it is on 4 which is the highest setting. My headlights will also blow but no other lights have blown while this issue had been present.

I have replaced the fan switch but that didn’t not fix anything. Have checked fuses and relays. Don’t see anything in wiring to cause an issue. Have not been able to figure this out! Been going on for 5 months at least.

All I know to do is put in line fuses in and buy bulk fuses for the price of bulbs so I just replace a fuse instead of a bulb and carry fuses with me to replace when they blow. I would really like to just get it fixed though.