Mac Tip - What mAh Means for Batteries

Looking to purchase a Ramjet battery but confused by some of the terminology? Today we'll look at what mAh means and how it relates to the life you will get out of your battery.

mAh is shorthand for milliamp hours, which is how electronic power over time can be measured. With a higher milliamp rating, the fully-charged battery is capable of powering a device for a longer amount of time, or capable of powering a device that consumes more power. Different manufacturers measure their battery capacity in slightly different ways, but for the purposes of a laptop battery, you can generally assume that a battery with a rating of 1500mAh could operate a device drawing 1500mAh of power for one hour.

However, how much power your Mac laptop draws can vary a little depending on the day. Lithium Ion batteries, for example, are sensitive to temperature, and discharge more quickly in warmer temperatures. It is difficult to get a concrete evaluation of battery life given some natural variation from day to day.

Luckily, your Mac laptop will estimate your remaining battery life without you having to do any math with mAh capacities and how much power your Mac might be drawing. Clicking the battery icon in your menu bar when the laptop is unplugged will bring up a drop down menu showing an estimate of how long you have left in your battery life. You can also click the "Show Percentage" option, and the default display will change to show the remaining percentage of battery life in the menu bar.

Another feature Mac has included helps you identify when your battery is no longer maintaining capacity as it used to and is in need of replacement. If you hold down the "Option" key while clicking the battery icon, you will notice a different option appears: a "Condition" report.
Condition: Normal means your battery is in normal functioning condition and does not need to be replaced or service.
Condition: Replace Soon means your battery is currently functioning normal, but is holding less charge than it did while new and may need to be replaced soon.
Condition: Replace Now means that while your battery is currently functioning normally, it's holding significantly less charge than when it was new and you should replace your battery before it ceases to function normally.
Condition: Service Battery means that your battery is not functioning normally, or that your computer is no longer communicating normally with the battery. You should either replace the battery immediately or take it to be serviced before any damage is done to your computer.