Understanding Battery Amp Hours

When it comes to judging battery life, one of the most useful tools we can use is the battery’s amp hour rating. However, while amp hours can tell us about the battery’s capacity, they don’t work exactly the way you might expect. As with most things, the calculations that go into battery building are more complex than the average person cares to know. Fortunately, we have a quick and easy guide to help you understand what amp hours really mean and how to read them when you are battery shopping.

Finding the Amp Hour Rating

Before you can compare batteries, you first need to know where to look for amp hours on your battery. If you are looking at deep cycle batteries, the amp hour rating will be clearly displayed on the battery or on the associated sales information. If you are unable to find an amp hour rating on the battery you are looking at, it’s probably because you are looking at a starting battery which is not built to provide continuous power in amp hours. Make sure you’re looking at the right type of battery.

What are Amp Hours?

Amp hour is the rating used to tell consumers how much amperage a battery can provide for exactly one hour. In small batteries such as those used in personal vaporizers, or standard AA sized batteries, the amp hour rating is usually given in milli-amp hours, or (mAh). For large batteries, the rating is abbreviated as Ah. Most deep cycle batteries will tell you the Ah rating at multiple C ratings. The C rating tells you how many amp hours the battery can provide for a very specific period of time. For instance, at C/5 a battery might safely provide 26.8 amp hours. This means that is supplies 26.8 amps in the duration of 5 hours without dropping off. Meanwhile, the same battery may safely provide 36 amp hours for a period of 100 hours. Depending on the amount of use you intend to get out of your battery (daily versus sporadically), you will want to compare amp hours for different C ratings. However, if you aren’t sure which C rating to use, it is best to go with the C/20 because it is the middle ground and will give you a general sense of battery performance.

Why More Amp Hours for Longer C-Ratings?

You may be wondering why it is that a battery provides more power when it runs longer, rather than less power. It would be natural to think that a battery running for 100 hours should provide fewer amp hours than a battery that only runs for five, because the battery must preserve power to make it last. The truth is that rapidly discharging batteries causes them to produce a lot of heat. This heat negatively affects the battery’s efficiency. Thus, when you rapidly discharge a battery with a C-5 rating, you are losing some of its available power just because the battery gets hot. Meanwhile, the C-100 battery is discharging at a much gentler pace and will be far more efficient.

Knowing how many amp hours your battery provides is the key to getting a battery that will support you through your daily routine. You don’t want to buy a battery that is short on capacity. For more information, contact the battery experts at MK battery today.

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