kWh × 1,000 / V =
0.00 Ah
Conversion formula: Ah = kWh × 1,000 / V
What Is Kilowatt-Hours?
Kilowatt-hours is a unit of electrical energy that represents the amount of power (in kilowatts) used or generated over a given number of hours. By this, one kWh equals the discharge or consumption of one kilowatt of power for one hour.
What Is an Amp-Hour?
Amp-hours (Ah) is a unit of electrical charge typically used to describe how much electrical charge a power source – such as a battery – can store. When used to describe how much charge a battery can store, it is called battery capacity.
Amp-hour represents the amount of electrical charge leaving a power source for one hour. In other words, it is the amount of charge a power source can offer for one hour.
How to Convert Kilowatt Hours to Amp Hours (kWh to Ah)
- To derive the conversion formula, we’ll start with the formula for amp-hours (Ah). This is also the formula that the watt-hours to amp-hours calculator uses to convert the two units:
\(ampere\mbox{-}hours = \displaystyle{\frac{watt\mbox{-}hours}{voltage}}\ (1)\)
- We can rewrite (1) as:
\(Ah = \displaystyle{\frac{Wh}{V}}\ (2)\)
- Next, we’ll define the relationship between Wh and kWh:
\(Wh = \displaystyle{\frac{kWh}{1000}}\ (3)\)
- Now, we’ll substitute Wh for kWh x 1000 in (2):
\(Ah = \displaystyle{\frac{kWh*1000}{V}}\ (4)\)
- The (4) is the conversion formula for kilowatt-hours (kWh) to ampere-hours (Ah).
Basically, to convert kilowatt-hours (kWh) to amps-hours (Ah), multiply kWh by 1000, then divide by battery voltage. This is what happens under the hood of a conversion calculator.
Going by the formula, we need voltage to do amp-hours-kilowatt-hours conversions.
Example 1: How to Calculate Amp-Hours of a Battery
If we have four 12V rechargeable solar batteries connected in series, they discharge a total energy equal to 0.2 kWh. What is the cumulative capacity of the batteries?
First, we must calculate the total voltage of the batteries. Since the batteries are in series, the total voltage would be:
\(12 + 12 + 12 + 12 = 48\ volts\)
Next, we’ll convert kilowatt-hours to ampere-hours using the total voltage:
\(Ah = \displaystyle{\frac{0.2*1000}{48}} = 4.17\ Ah\)
Example 2: Comparing the capacities of two batteries
We have one 12V battery that discharges a total energy equal to 0.8 kWh and another rated 80 Ah. Which of these batteries has the larger capacity?
Since we know the voltage and kilowatt-hour of the first battery, we’ll start by converting kilowatt-hours to ampere-hours:
\(Ah = \displaystyle{\frac{0.8*1000}{12}} = 66.67\ Ah\)
Next, we’ll compare the Ah of both batteries. Obviously, the battery rated 80 Ah has a larger capacity than the 0.8 kWh battery, which has an Ah capacity of 66.67.
Kilowatt Hours to Amp Hours Conversion Chart
Reasons to Convert Kilowatt-Hours to Amp-Hours?
Estimating the Size of a Battery Bank To Meet Energy Demands
When trying to size the ideal battery bank to meet our energy demands, knowing the average energy consumption of the load we intend to use on the battery is only the first step.
Most battery banks come with a capacity rating of Ah. Contrarily, electrical energy consumption is typically in kilowatt-hours (kWh) or watt-hour (Wh). So, to figure out the Ah that will meet the energy demands of the load’s kWh, we must do a kWh to Ah conversion.
Calculating Battery Characteristics
Quantities like charge current, discharge rate, and charge rate, which define battery characteristics, depend on battery capacity in amp-hours. As such, when calculating them, we need to know Ah.
So, if the capacity of a battery comes in kilowatt-hours, we’ll have to do a kilowatt-hours (kWh) to amp-hours (Ah) conversion [kWh to Ah].
How to Calculate Kilowatt-Hours to Amp-Hours
By rearranging the formula for kilowatt-hours (kWh) to amp-hours (Ah) conversion, we can get the formula for converting ampere-hours to kilowatt-hours (Ah to kWh).
- So, if the formula for a kilowatt-hour (kWh) to amp-hour (Ah), the conversion is:
\(Ah = \displaystyle{\frac{kWh*1000}{V}}\ (1)\)
- When we make kWh the subject of (1), the formula becomes:
\(kWh = \displaystyle{\frac{Ah*V}{1000}}\ (2)\)
- Going by (2), multiplying amp-hour by voltage to convert amp-hour to kilowatt-hour. Then divide by 1000.
The Difference Between Ampere and Ampere-Hours
The difference between ampere and ampere-hours is the unit they measure. While ampere measures electrical current, ampere-hours describe the quantity of current flowing from a power source over one hour.