What Do Amp Hours Actually Tell You About a Battery?

As you shop battery listings online, you will discover that batteries are described using a variety of different rating methods. Amp hours, cold cranking amps, cycles, and more are used to describe the type of battery you are buying. If you are not familiar with these terms, it is important to learn what they mean before you buy so that you can get the right type of battery for your application. Here, we will discuss what amp hours really mean and what they do and don’t tell you about a battery’s performance. 

What Is an Amp Hour?

Technically, an amp hour is simply a measure of how long a battery can provide one amp of power per hour. You will see it abbreviated as Ah or mAh for milli-amp hours in small applications. Unfortunately, most of the devices we rely on do not draw exactly one amp of power per hour, so an amp hour is not a particularly useful rating in this form. Instead, we have to consider what the amp hour rating means in relation to other factors about our device. 

Battery Capacity

In a broader sense, the amp hour rating does tell us a little bit about the battery’s capacity. For instance, a battery with a 10 Ah rating will last twice as long as a battery with a 5 Ah rating when used under similar conditions, but it does not mean that it will actually last 10 full hours. This is an important distinction to make because certain applications are more demanding than others. For instance, a mobility scooter driving through a hilly neighborhood will put more strain on a battery regardless of its amp hour rating, but a battery with a higher rating will be better able to handle that strain and have power left over. 

Battery performance will also be determined by the voltage ratings of the battery, which ultimately affect how the power is used by the device. You can find batteries with a wide range of voltage and Amp hour ratings to suit different applications, so the voltage of a battery does not necessarily tell you what the amp hour rating could or should be, and vice versa. While these two variables do affect one another in practice, they operate independently of one another for the purposes of describing a battery’s capacity and power. 

The most useful way to use amp hour ratings is usually when comparing two different batteries side by side. In this way, you can easily see that the battery with the higher amp hour rating will need fewer recharging stops if all other factors are equal. Once you have your battery installed and you put it to the test, you will be able to see how long the advertised amp hour rating actually holds up under your specific circumstances. However, you will also need to keep in mind that as a battery ages it does start to lose some of its capacity, which may affect you long term. Generally, when a battery starts dying faster and faster with each recharge, you know it is time for a replacement. 

For more information about comparing batteries for your medical devices and other applications, visit MK Battery online.