What Is Ah In Batteries?

What Is Ah In Batteries?

Ever wondered what Ah in batteries is? To understand what this is, you need to know what a battery really is. One thing to know is that there are different types of batteries but it is important to know that they all work the same way. A battery can be described as a device that is capable of storing electrical energy that is in the form of chemical power and transforms it into electricity. One thing to know is that electricity cannot be captured and preserved but you can store electrical energy in the chemicals present in a battery.

Ah in batteries is the short form for ampere hours and it can simply be defined as the amount of energy or current a battery can hold or supply over a period of time. The Ah rating in batteries offers a way to measure the capacity of a battery and with it, you will know which batteries last longer than which. There are certain information about what Ah in batteries in which people do not know. But we have decided to shed a little light on them in this article. Kindly read on and we are sure this will not be a waste of your time.

What To Know About Ah In Batteries

In the paragraphs that follow this, we will be writing about what we feel you need to know about the Ah in batteries and information about batteries in general.

How To Calculate Ah in Batteries?

As we have said in previous paragraphs, the Ah in batteries is the capacity of the battery to hold power. It can be calculated by multiplying current by discharge time. That means Amp X discharge time. A current can simply be referred to as the rate at which electricity passes through a battery and is usually measured in amps. Discharge time is the time it takes the battery to completely use up the electricity stored in it. Now, we will show you the calculation of the Ah battery below:

We will assume that the current = 10 amperes and the discharge time = 15 hours. Therefore, the Amp hour rating of the battery will be calculated as:

Ah= Current X Discharge time. Which means 10 amperes X 15 hours.

Therefore, Amp hour = 150 Ah.

From the calculation we showed above, the Ah rating of the battery will be shown as 150 Ah @ 15 hours.

What Happens To The Ah Capacity In Batteries When Not Charged?

When batteries are not charged for a long time, it leads to sulfation. And when this happens, the Ah capacity of the battery will become reduced significantly. This means that the battery will not be able to hold a charge for long. When this happens, you might be forced to change the battery earlier than you should. This is why it is advisable for you to charge your battery from time to time even when not in use.


How To Test Ah Capacity In Batteries?

Now that you have learnt how to calculate the Amp hour in batteries, the next thing to do is to try to test the Ah capacity in batteries. We are going to be focusing on a 12-volt battery and all you need is a light bulb, an electric clock and the battery you need to test. The reason this test is important is that sometimes the hours indicated that the battery will last for by the manufacturers might be false. To be on the safer side, you will need to test the battery yourself and we will be writing on the simple steps involved.

Step 1: Get A Battery Tester

A battery tester is a very common appliance for battery owners and if you do not have it, you can always get it from any electrical shop around. This tester has a voltmeter which as its name implies, it is used to check the voltage of a battery. In addition, the battery tester has a switch that always turns on an extremely low resistance dummy load. This is useful for checking out the current the battery you are testing is capable of generating.

Using a battery tester like this is very safe compared to most other types of ways to test batteries. With this type of tester, you are assured that your hands won’t get burnt in the process of testing batteries.

Step 2: Charge The Battery and Perform A Voltage Test

Before a battery can be tested, you need to get the battery charged. Make sure the battery is fully charged before you even try to test its voltage. To charge the battery, we advise that you connect the battery to a 2 amp battery for about 36 hours. If the battery is up to 200 amps, then you will need more days to charge if you will be using the 2 amp charger. To know if a 12-volt battery is fully charged, hook the battery tester to the battery and read the voltage rating. The tester should read over 12.4 volts if it is truly fully charged.

However, using voltage as the unit of measuring a battery’s charge is not as reliable as using hydrometers. We advise that to be on a safer side, charge the battery till the voltage reaches as high as 14 volts. That way, you can rest assured that the battery is fully charged.

Step 3: Current Test

There’s a button on the battery tester that needs to be pushed in order to short the battery out through a low ohm resistor. When you push this button, the meter of the tester moves right and it tries to reach the amp indicators on it. The rating on the tester will tell you if your battery is good or not. If it passes the bad markings indicated on the battery, then there is a probability that the battery is good. If it doesn’t, then there’s no need to test the capacity of the battery. You might wonder why the battery’s capacity is being tested after the battery passing the current test. This is because there are instances when batteries pass but their capacities are nothing to write home about.

Step 4: Set Up The Capacity Test Rig

Get the electric clock, a 60-watt bulb and connect it to the battery using an inverter. The next thing to do is to start the clock at 12:00 hours and check the clock to see how long it took for the 60-watt bulb to go off.

The calculation:

The 60 bulb draws out 5 amps from the battery

Watts = Amps X Volts.

The 60 watt bulb = 12 volts X 5 Amps

5 Amps = 60 watt/ 12 volts.

With this calculation, you will be able to know the time it takes the battery to figure out how long the Amp hour of the battery is.


We are sure that the question: “What is Ah in batteries” has been answered. We hope you learnt a great deal from this article. We enjoyed writing this article and we hope you enjoyed reading them too.

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Hi James,
Wow, that’s an excellent way to explain “How To Test Ah Capacity In Batteries?.” I read almost 4 blogs from other sites, but my confusion was still. After reading this very informative blog on “How To Test Ah Capacity In Batteries?,” I clear all my doubts and know the way Test Ah Capacity In Batteries. Thanks for sharing such valuable information.

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