Amaron Tall Tubular AR200TT54 (200ah) Battery 200AH Tall Tubular Battery Amaron 200ah battery with inverter price HB1250VA Ups With AM200TT54 Tubular Inverter Battery 200ah 54 Months Warranty How many hours does a 150Ah battery last You can expect your 200 Ah battery to last for around 5 hours on 450 watts bulb load if it is fully charged. If the load or appliance wattage is reduced the backup will improve. The formula for calculating the inverter battery backup time is straightforward: Backup time (in hours) = Battery capacity (Ah) x Battery voltage / Total load (in watts). For example, if your inverter has a 200Ah battery and operates at 12V with a load of 350 watts, the backup time will be approximately 6 hours.