Battery Life Calculator

Capacity rating of battery (mAh) mAh = milli-Amp-hours
Current consumption of device (mA) mA = milli-Amps

Enter your battery capacity rating in (mAh). Change the default example of 250 to another number.

Enter the current consumption of your device in (mA). Change the default of 20 to another number.

Click battery life calculator button to see the estimated battery life result.

The output of this calculator does not guarantee that you will get the determined battery life. Other factors such as battery load, weather condition (temperature, humidity, etc.), and battery condition can extend/shorten the battery life. This calculator is not valid for alkaline batteries

Generally, battery life is calculated based on the current rating in milli Ampere per Hour and it is abbreviated as mAh. Ampere is an electrical unit used to measure the current flow towards the load. The battery life or capacity can be calculated from the input current rating of the battery and the load current of the circuit. Battery life will be high when the load current is less and vice versa. The calculation to find out the capacity of battery can be mathematically derived from the following formula:

Battery Life = Battery Capacity in Milli amps per hour / Load Current in Mill amps * 0.70

Battery capacity is a measure (typically in Amp-hr) of the charge stored by the battery.

Battery Ratings, Variables and Losses

An approximate measurement of a battery’s ability to provide energy i.e it’s charge capacity, is it’s rating in ampere hours (Ah) or amp hours.

So a 100 Ah battery will produce 100 amps for 1 hour.

This capacity can be divided up any way you choose.

100 Ah could produce 1 amp for 100 hours, or 50 amps for 2 hours, 4 amps for 25 hours or 25 amps for 4 hours etc.

Battery capacity (Ah) = Current drawn (I) x Time (H)

or you could cross multiply and get..

Time = Battery capacity / Current drawn

Current drawn = Battery capacity / Time

So when choosing a battery for your set up, you need to know how many amps you will be drawing and for how long.

There are other things that also need to be taken into consideration when calculating a battery’s useable capacity.

When you discharge a battery by consuming the power stored in it, you should never discharge it beyond a certain point, otherwise you risk damaging it’s future storage capacity.

The maximum discharge level depends on the type and quality of the battery.

No matter how good the battery is, if you want it to last and not pack up after a few months of use, it is generally accepted that you should never discharge a battery by more than 50% of it’s capacity.

You must also take into account, the battery’s listed ‘amp hour rating time’ when you buy it, and the speed that you intend to drain the battery when you use it. These two factors can dramatically affect the battery’s capacity.

Tips on maximizing your cell phone battery life.

Saving your battery life isn’t rocket science—the general principle is to get rid of the things that are draining the battery the most, and trim down other things that you need to use.

Use Android’s Built-in Battery Usage Screen

Head into Settings –> About Phone –> Battery use to see what has been killing your battery life.

From this screen, you can usually see what apps are the worst offenders, and you will probably notice that the biggest problem—at least, the biggest one that we can fix—is actually the backlight on the phone.

Disable Your Wi-Fi (wifi) When You Don’t Need It

Disable Bluetooth if You Don’t Use It

Disable Apps that Sync Constantly

Disable the GPS Location Features (When there not needed.)

Use a Task Manager to See What is Always Running

It is a wise decision to have a copy of Advanced Task Cleaner or a similar application installed on your phone to help you kill applications that don’t need to be running, but more so that you can see what exactly is launching itself repeatedly in the background.


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