Amp Hours to Kilowatt Hours (Ah to kWh) Conversion Calculator

What Is Amp Hour? What Does Ah Mean on a Battery?

Amp-hour (also ampere-hour) represents the amount of electric charge that a power source will discharge within one hour at a given voltage.

Amp-hours (Ah) is used to represent the capacity of most batteries. Although, in some cases, the metric prefix – milli – may be added to it, changing the unit to mAh.

What Is Kilowatt Hours (kWh)?

Kilowatt hours is a unit used to measure electrical energy. It represents the energy used up owing to a given amount of power consumed over one hour.

The SI unit of energy, including electrical energy, is Joules (J). However, when it comes to electrical energy, kilowatt-hour (kWh) is preferred.

How to Calculate Ah to kWh

Conversion Formula

We’ll start by deriving the conversion formula of ampere-hours to kilowatt-hours. First, since kWh is a measure of electrical energy, we’ll start with its formula:

electrical energy (kWh) = power (W) x time (h) ÷ 1000

we can represent that as:

kWh = W x h ÷ 1000 (1)

Next is the formula for power:

power (W) = voltage (V) x electrical current (A)

we can rewrite that as:

W = V x A

we’ll substitute V x A for W in (1)

kWh = V x A x h ÷ 1000

we can rewrite that as:

kWh = V x Ah/1000

now, we have our conversion formula:

kWh = V x Ah/1000

Going by the formula, to convert ampere-hours to kilowatt-hour, multiply Ah & volts then divide by 1000. This is what our Ah to kWh conversion calculator and pretty much any other Ah to kWh calculator do.

Example: How to Calculate Kilowatt Hours of a Solar Battery

Let’s say you have a solar system with a 200 amp-hours (Ah), 12V solar battery, but you want to know the battery capacity in kilowatt-hours (kWh).

You can convert the 200 amp-hours to kilowatt-hours by simply doing this:

kWh = 12 x 200/1000 = 2.4 kWh

The solar battery has a capacity of 2.4 kWh.

How to Convert Milliamp Hours to Kilowatt Hours (mAh to kWh)

As mentioned earlier, sometimes battery capacity is written as milliamp-hours (mAh) instead of amp-hours (Ah). So, if we ever find ourselves with mAh instead of Ah, how do we do a kilowatt-hours (kWh) conversion?

Converting mAh to kWh is as straightforward as converting amp-hours to kilowatt-hour. All we have to do is multiply mAh and volts then divide by 1,000,000 instead of 1000.

kWh = V x mAh/1,000,000

Example:

Let’s say we have a 12V power bank battery rated 5000 mAh. We can convert it to kilowatt-hour by doing this:

kWh = 12 x 5000/1,000,000 = 0.06 kWh

The 5000 mAh solar battery has a capacity of 0.06 kWh

Why Convert Amp-Hours to Kilowatt Hours (Ah to kWh)?

Ordinarily, when comparing our energy needs to the capacity of a battery, we do a kilowatt-hours (kWh) – amp-hours (Ah) conversion. But we could also convert the battery’s capacity (Ah) to kilowatt-hours (kWh) then compare with the required energy.

When comparing the capacity of two or more batteries, we may also have to convert amp-hours to kilowatt-hours (Ah to kWh).

Normally, we can just compare the battery capacity of two batteries in Ah if they have the same voltage. But if they have different voltages, we’ll need an Ah to kWh calculator.

A direct comparison of the battery capacities of batteries with different voltages will give us an inaccurate result. Why? Well, the energy stored in a battery is dependent on Ah & volts. So, if we’re making a comparison that excludes the value of voltage, our estimation would be off.

Example:

If we have two batteries A and B, with battery A rated 100Ah, 12v and battery B rated 100Ah, 12v, we can easily conclude that they both have the same capacity. This would not be inaccurate because they have the same voltage.

However, if battery A is rated 100Ah, 20v and battery is rated 100Ah, 12v, they wouldn’t have the same capacity anymore. Even though they have the same capacity in amp-hours, the amount of charge they store will not be the same. Plus, we’d have to convert amp-hours to kilowatt-hours with an Ah to kWh calculator to even make an accurate comparison.

Amp Hours to Kilowatt Hours Conversion Chart

Here are two quick Ah to kWh conversion charts. They feature kWh values for common battery voltages, 12v and 24v. With these, you wouldn’t need an Ah to kWh calculator sometimes.

For a 12v battery:

The Difference between Kilowatt and Kilowatt Hours

At the simplest, kilowatt is a measure of power while kilowatt-hour is a measure of electrical energy.

Kilowatt is basically watts with the metric prefix kilo. It represents one thousand watts. Since watt is the rate at which energy is transferred per second, we can say kilowatt is the rate at which energy is transferred per millisecond.

Kilowatt-hour, on the other hand, is the energy consumed when 1000 watts (1 kW) is used up over a 1-hour period.

Watt Hours vs Kilowatt Hours (Wh vs kWh)

The primary difference between watt-hours and kilowatt-hours is their magnitude. Because kilowatt-hours comes with the prefix kilo its magnitude is in thousands. With watt-hours, there’s no metric prefix, so the magnitude is in units.

So, while kilowatt-hour (kWh) is the energy consumed when 1000 watts is used for one hour, watt-hour is the energy consumed when 1 watt is used for one hour.

Share in social: