How Long Will my Battery Last?

9th Jul 2014

There is no denying the fact that rechargeable batteries are more cost effective and easy-to-manage than disposable or primary batteries, but often people don’t have adequate knowledge about the charge and discharge cycles of these batteries. They don’t know about some technical problems that may impact the effective life span of rechargeable batteries and cause irresolvable problems. This article will highlight some practical examples and help you improve the performance of your batteries. 

Charging the Battery at the Right Time 

In order to keep track of the charge and discharge cycles of your battery, you must know how long your rechargeable battery will last until it needs to be recharged (or relaxed in case of any permanent issue). There are a number of factors that directly influence the time or duration in which batteries can function effectively without being recharged. 

Some of these factors are: 

  • Charge storage capacity of the battery (measured in Ampere-Hour) 
  • Power requirements and voltage ratings of the device using the battery 
  • Chemistry of the battery 

There are two simple ways to determine the amount of charge of your battery. 

Method #1 

If you know the effective storage capacity of the battery (mentioned by manufacturers) you can easily determine the run out time of the battery. A standard 1AH rechargeable battery usually has 1 hour of running time at a draw of approximately 1 ampere, until it needs to be recharged. The same battery will run for 2 hours for the devices operating at a ½ Amp draw, and ½ hour for the devices running at 2Amp draw. It means that the amp draw of the device connected to the battery is inversely proportional to the running time of the rechargeable battery. 

Method #2 

If you have precise information about the capacity of your battery and the amp draw of the device connected to it, you can tell exactly how long your battery will last. You can also determine the capacity or power a device will require to function for a certain time period. 

If a particular device requires 2 amps to run and the rechargeable battery you are using is drawing more than 2 amps (e.g. 3 amps), the battery will run for about 1-½ hours. All you have to do to determine the run time of the battery, and divide the AH of the battery by the current drawn by the device connected to it. In this case, we divide 3 (AH of battery) by 2 (Amp requirement of the battery) to get the run time of the effective battery. 

In order to evaluate the capacity or the amount of charge needed by a device, simply multiply the amount of current drawn by the device by the amount of run time (in hours). For example, if the device needs 10 amps of current and needs to be used for 4 hours, the you will need a 40AH battery to keep the device running for 4 hours (10A x 4hours = 40AH).