Unlike hundreds of calculators available on internet for battery backup calculation, our calculator is designed based on actual battery manufacturer data providing up to 90% accurate result whether you are sizing your batteries in Watts (W) or Amps Hour (Ah), while other free calculators available over internet only reach the accuracy of up to 50% and yet you still need to perform your own research to figure out whether the battery size calculated even exists. For example, you need 3000Ah battery as per calculator, however you do not know whether 3000Ah battery actually exist. It will be great if it does. If it does not, then this is a type of question which our calculator can answer and assure you to get result within standard battery sizes available in market.

I know you are thinking why our calculator is only 90% accurate. So here is the secret. It is not possible to achieve 100% accuracy in battery calculation because of multiple technical factors which play important role in battery calculation. Such as battery operating temperature, battery type, battery chemical composition, environment, battery efficiency, battery heat losses, battery ageing, battery cable losses, connected load efficiency, connected load losses and proper termination of battery. These are few types of technical factors which need to be considered, and it is often hard to estimate them as the values keep changing from scenario to scenario and time to time. Therefore, one cannot promise 100% accuracy when sizing the battery. But If you are aiming, to achieve higher accuracy and have good technical knowledge how battery works and operate? Then you might want to try our advance calculator which gives you more freedom to play around with multiple battery parameters to calculate to appropriate battery size for desired backup time.