Over time batteries lose their designed capacity thus reducing the backup.
Inverter backup time reduced.
Back up time of inverter battery battery volt x battery ah rating total watts on load so if a person use 1 ceiling fan 1 tube light 2 15watts cfl simultaneously with 150 ah battery then the backup time will be calculated as.
Like if your load is half 440 watt then it will give double backup around 6 hours.
2 battery has worn out.
Change the batteries of your inverter if they are worn out.
1 too much power consumption.
Top up flooded lead acid battery with distilled water regularly.
Most battery backup inverters were designed for 200 amp home electric services.
The inverter backup time is can be computed using this formula best time in practice the actual time will be less than this.
Possible cause remedy.
The battery inverter s maximum power output in kilowatts is the second reason for the whole home backup myth.
If the inverter is still functional a maintenance manager might be tempted to simply ignore these signs of wear and tear.
Here is a quick guide on calculating inverter and battery backup time.
1 ceiling fan 75 watts.
Battery ah 2 150 300 ah.
1 tube light 40 watts.
There are the different capacity of inverters like 200va 250va 350va 400va 450va 500va 625va 1200va etc.
Math time backup frac voltage battery times ahrating battery load math so if you have two 15w bulbs a ceiling fan rated at 100w say total load is 125w.
However as the saying goes it s better to be safe than sorry so cleaning the terminals in the battery box fuses and the inverter connection at least once.
Remember that if you run only one ceiling fan 75 watts with 150 ah battery the expected backup time will be 15 to 16 hours.
Backup time is shortened.
Formula to calculate the back up time of inverter battery.
Buy good quality batteries that will last longer and also guarantee the correct charge storage capacity.
Actually if you run two ceiling fans 75 75 150watts simultaneously with 150 ah battery you were drawing more than 95 watts so clearly the backup time will be reduced and you can expect only 5 to 6 hours backup.
If your load is less than 880 watt then it will give more backup.
So with 1100 va inverter and 150 ah battery you can use maximum of 880 watt load for 3 27 hours.
4 battery has lost electrolyte.
If charger appears to be faulty get ups inverter fixed.
3 battery is not properly charged.
The load of the inverter should be chosen based on how many watts of appliances you power at a time.