Battery Life Calculator
This battery life calculator calculates the battery life of a battery in a circuit.
The battery life is the amount of time, normally specified in hours, that a battery will last in a circuit.
How long a battery will last is determined by 2 factors, the battery capacity and the load current of the circuit. Both of these factors are explained in detail right below.
The battery capacity of a battery is the amount of current in total which a battery can supply fresh out of manufacturing. All batteries come with a battery capacity rating. This, again, is the total amount of current that a battery can supply in milliamperes during its lifetime. Therefore, if a battery has a battery capacity rating of 2000mAH, it can supply 2000 milliamperes of current during its lifetime. This means it can supply 20mA for 100 hours, 200mA for 10 hours, 2A for 1 hour, etc. since the product of all these equals 2000mA. To learn more in detail about battery capacity, see mAH rating of a battery. Battery capacity is measured in unit milliampere-hours.
The load current is the amount of current which the load of the circuit consumes; or, in other words, it is the amount of current being drawn in the circuit, the total amount of current being used. It is important because since the battery is the power source, it is from the battery that the current is being drained from to power the load. The more current which the load or circuit consumes, the quicker the battery becomes drained, since more current is being used. The less current which the load consumes, the longer the battery lasts, because less current is being drained from it. Therefore, if we use a less demanding load in a circuit, it will allow the battery to live longer. If we use a load which requires a great amount of power (in the form of current), the battery will be much shorter. So the load current is inversely proportional to the battery life. The load current is measured in unit milliamperes (mA).
To use this calculator, a user enters the battery capacity and the current load, and clicks the 'Calculate' button. The resultant battery life is then calculated and displayed, according to the product of the battery capacity and current load, seen in the formula above. The resultant battery life is in unit hours (h).
Battery life is of course very important in electronic circuit design. Depending on the amount of load current needed for a circuit, how long the battery power will last is very important for consumer satisfaction. The batteries in use should last at least a number of hours for consumer satisfaction. No one wants a battery to die after only an hour of use for an electronic gadget. So calculating battery life is essential when building a circuit. Usually since electronic circuits usually consume current in the low milliamperes (20ma-50mA), normal batteries will last hours and hours (50-100 hours), since normally batteries have a battery capacity range of 1700mAH to 3000mAH.
Also note that though that this calculator cannot be used as an exact battery life calculator but more as an estimator. This is because battery life is
also greatly affected by other factors such as temperature, humidity, usage. These can all play as variables in how long the battery will last.