Introduction
Volts, amps and watts are electricity measurements.
Volts measure the electrical potential, or the “push,” that moves electrons through a circuit. In simpler terms, volts tell you how strongly electricity is being pushed along. Electricity delivered to buildings is typically at two "pressures": 120V or 240V. In a solar system, the inverter delivers this electricity in place of the plugs in your home.
Amps (amperes) measure the flow of electric current, or how many electrons pass through a given point per second. In terms of appliances in your home, smaller appliances need to be connected to lower amps, such as 15 or 20 amps. Larger appliances like washing machines or refrigerators are generally connected to circuits providing 30 amps.
Watts measure the rate at which energy is used or transferred. You’ll often see this rating on light bulbs and appliances, indicating how much power they draw.
The formula for watts, volts and amps calculation are as follows:
Watts = Volts x Amps
Amps = Watts / Volts
Electricity Measurements for Home Appliances
Below are some common household appliances with approximate watt, volt, and amp ratings. Actual values may vary based on specific models and brands, but these examples provide a general idea.
How Do I Use the Calculator
If you’ve got a solar power system set up, one of the most important things to remember is that you should never deplete your inverter or battery completely.
To avoid this, we need to know what we can plug into it, and how long we can run it for. For example, if you opt for a tiny inverter, it won’t be able to handle something like a hairdryer being plugged into it.
Scenario of Example Solar Setup
Inverter Size: 500 watts(W)
Battery Voltage: 12 volts(V)
Battery Capacity: 500 Watt-Hours (Equal to 42 Amps-Hours at 12V; 500 / 12 = 42 Ah)
Suppose you have a fan labeled 100 W, which is under inverter output 500 watts, so the inverter can safely run it. Then, calculate how long the battery can supply this power before depleting.
If you run the fan for 3 hours, it consumes 100×3=300 Wh. Since the battery is 500 Wh, running the fan for 3 hours uses about 300 Wh. That’s within the battery’s capacity, leaving around 200 Wh of usable power (before it's fully depleted).
Now consider a hair dryer labeled 1200W. Compare it to your inverter’s 500W rating. Since 1200W > 500W, the hair dryer will overload your inverter—it simply can’t provide that much power.
If you had a bigger inverter (let’s say 1500W) and 500Wh battery life. At 1200W, it would theoretically use 1200 Wh in one hour. The 500Wh battery is much smaller, so it could only run that dryer for about 25 minutes in perfect condition. If you fully drain the battery, it will shorten its life.
If you have any uncertainties with choosing solar kits for your residential or commercial use, you may contact us at PrimeService@self2solar.com.
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