As the technology of solar power generation becomes more and more mature, many industries are beginning to use solar panel systems to generate electricity instead of the traditional burning of fossil fuels to generate electricity. Among them, solar panel systems for homes are one of the more widely used and mature industries. In modern homes, people have a greater demand for electricity, but in order to reduce the upfront investment costs, under the premise of installing smaller-scale solar panel systems, there are many ancillary equipment to help improve the power supply capacity of the solar panel system, of which the solar battery pack is one of the important ancillary equipment. In order to better understand and recognize the relationship between solar banks and solar panels, we need to learn the relevant electrical knowledge. In this article, we will introduce you to the knowledge about Ampere-hour and Kilowatt-hour, and learn the conversion method between the two.

1. What is Ampere-hour (Ah)?

Ampere-hour is the main unit of electricity of a solar battery pack, referred to as ampere-hour, which refers to how much electricity can be output from a battery in the process of discharging for 1h. The source of its calculation, is the current in the circuit in amperes (A) as a unit of measurement, the running time in hours (h) as a unit, multiply the two, you can get the ampere hours, that is:

E (Ah) = I (A) × T (h) ①.      

2. What is kilowatt hour (KWh)?

Kilowatt hour is a unit of energy, symbolized as KWh. it is often used as a unit of energy consumed to operate an electrical appliance. 1KWh is defined as the amount of energy consumed by an appliance with a power of 1KW or by a battery with a discharge power of 1KW to operate for 1 h. It is the unit of energy consumed by an electrical appliance. The source of its calculation is:

E (KWh) = V (KV) x T (h)  ②   

It is important to note that ampere hours and kilowatt-hours are not units of measurement of the same physical quantity; ampere hours are units of electricity, while kilowatt-hours are units of electrical energy. Within a solar panel system, the ampere-hour is often used to describe the capacity of the solar array, but the kilowatt-hour is often used as a unit of energy that can be produced by the solar panel system.

3. How do I convert from ampere hours (Ah) to kilowatt hours (KWh)?

Because ampere hours and kilowatt hours are not the same unit of measurement for physical quantities, the conversion between the two cannot be done directly according to the multiples in the International System of Units (SI). In order to realize the conversion from ampere-hour to kilowatt-hour, we must introduce an intermediate physical quantity, which can be known by analysing the source formula of the two, that is, volts. Thus the formula for the conversion of the two is:

E (KWh) = {E (Ah) x V (v)} ÷ 1000

The following will give you an idea of where the formula is derived from, firstly, we can extrapolate forward from the conversion result, kWh, which as a unit of energy can be calculated by the following formula:

E (KWh) = P (KW) × T (h) ③

And P (KW) in the above formula can be calculated by:

P (KW) = V (KV) × I (A) ④

Calculated by substituting equation ④ into equation ③, resulting in equation ⑤ as:

E (KWh) = V (KV) × I (A) × T (h) ⑤

And the last two of the multiplication in equation ③ is the source of the calculation of ampere-hours, substituting equation ① into equation ⑤, which is:

E (KWh) = V (KV) × E (Ah)

Then convert the unit of voltage in the formula, kilovolts, to volts, which is:

E (KWh) = {E (Ah) × V (v)} ÷ 1000

After the above series of analysis and explanation, I believe you have understood about the source of the formula for converting ampere hours to kilowatt hours. Below will be an example of a solar panel system to help you better understand and grasp the above formula.

When you have installed a solar panel system for your property with a battery capacity of 1200Ah, and the operating voltage within the solar panel system is 110v, then according to the above formula for calculations, your solar panel can be compatible with a solar panel system with a power generation capacity of (1200Ah x 110v)÷1000=132KWh.