1985 southwind battery trouble ???

Hi my 1985 southwind Was running great, i left radio on over night and ran battery down it started with auxiliary start. Drove it about 10 miles. Always drive with headlights on. Lost gas pressure,stared to backfire and choke. Pulled over. It stalled. Shut off lights. Restarted. Gas back to normal,running ok. Turned light on and it started all over. Had to drive another 10 miles or so parked it for 6 hours. Wouldn't start without auxiliary start and did the same thing when i turned on lights, it was after dark so i had to stay parked over night(not pluged in) in the morning auxiliary start wouldn't work again so i got a jump. About 15 minutes almost started. Tryed engine staring fluid as I've had to use it before. Again almost turned over. Went and got some gas as i was low on that. It will only click without a jump. Any ideas? I just bought it and know absolutely nothing about cars or rv's. Have it plugged in now. Electrical panel indicates battery charging but i also hooked up the plug in 12 volt charger and its telling me it has 98% charge. You guys and gals all sound very knowledgeable, should i just go buy a new battery? The battery panel says they are charged the electrical panel has the red light on not flashing indicating its charging. That all i got so far from reading what few manuals i have. would really love to hear any ideas. thank you chenoa kai