How to Convert Amperage to Amp-Hours
Being able to convert amperage to amp hours is a useful skill. For example, one might do this conversion when determining the necessary size for a battery pack to be used with a solar panel system for an RV or cabin. Many people are confused by the components of electrical energy, usually expressed in terms such as volts, amperes (often shortened to "amps") and watts. Before beginning to convert amperes to amp hours, understanding how a couple of components of electricity work together is needed. Does this Spark an idea?
Instructions
-
-
1
Think of the energy in an electrical circuit in the more familiar terms of a water spigot and a garden hose. As you turn on the water spigot, pressure pushes water into the hose. This pressure is the same as the voltage in an electrical circuit. As you increase the pressure in the hose, more water flows through the hose. The amount of water flowing past a certain point, say, a sprinkler head, is the same as the number of electrons flowing in an electrical circuit, which is expressed as amperes, or amps.
-
2
Boost your understanding of the concept by determining how much water flows out of the hose over a given amount of time. As an example, if you set the water spigot to deliver five gallons per minute and left the water running for an hour, you could calculate that 300 gallons of water had flowed through the hose (5gpm x 60 minutes = 300 gallons).
Amps and amp-hours work the same way. If a circuit is delivering 5 amps to a light bulb, and the bulb remains illuminated for one hour, then you have expended 5 amp-hours, usually expressed as 5Ah.
-
-
3
Consider this concept useful because storage batteries are usually rated in amp-hours at a given voltage. For example, a common battery used in solar panel systems is rated at 220 amp-hours at 6 volts. A battery's capacity is often rated over a period of 20 hours. So, in the example above, the battery rated at 220 amp-hours would deliver 11 amps for 20 hours (220/20 = 11).
-
4
Take the same concept to much smaller batteries, such as those you put in your digital camera. You might have noticed that a AA cell for your camera is marked at something like 1200mAh. The "mAh" means "milliamp-hours." A milliamp is one thousandth of an amp, so a 1200mAh battery would be equivalent to a 1.2 amp-hour battery.
-
5
Try your hand at figuring some amp-hours. You have a water pump in your RV that is rated for 5 amps. During an average day, you estimate that the pump runs for a total of 45 minutes, which includes pumping the water for cooking, doing the dishes, providing drinking water, taking a quick shower, and flushing the toilet several times. How many amp-hours does the pump use each day? If your answer is 3.75 amp-hours, you're correct. Forty-five minutes is three-quarters of an hour, so the calculation is: 5 amps x .75 = 3.75Ah.
-
1
