When we need to heat up or cook food, our microwave is always the go-to appliance. Microwaves use less energy than other cooking appliances in the Kitchen as they do not really use heat but microwaves. 

Unless you are defrosting or making large quantities of food you won’t need to run a microwave in an hour’s time especially if you are off-grid and relying on solar power. In this article, we look at how much solar power you’ll need at different time intervals in order to get your microwave running. 

Solar Power for a 1000-Watt Microwave

So how much solar power will you need to run a microwave? The amount of power used by your microwave depends on how much food you’re heating up and how much time it takes for the water inside the food to turn into steam.

A microwave will require less power than an electric oven, even a small portable one. A typical microwave oven uses 1,000 to 1,500 watts of power. The wattage is determined by the size of the microwave and the number of features.

If you are running a 1000 Watt microwave over an hour you’ll need a 250 Watt solar panel with a 24v 200Ah LiFePO4 battery and a 1500 Watt inverter or higher. 

We take you through the numbers. 

Microwave Watt-hours requirements

Electrical energy is measured in watt-hours. The amount of power you use depends on the amount of time you run an appliance. 

Electrical energy is measured in watt-hours. The amount of power you use depends on the amount of time you run an appliance. The wattage tells you how much energy the appliance uses, but not how long it will last. 

For example, a 200-watt computer running for 2 hours uses 400 watt hours, while a 60-watt bulb running for 4 hours uses 240 watt-hours.

Watt-Hours = Watts X Hours 

So if you are using a 1000 Watt Microwave for 1 hour then you’ll need 1000 Watt-hours which is equal to 1Kwh. 

What Size Solar Panel for a Microwave?

In order to determine how many solar panels are needed for your particular situation we simply divide the total watt-hours required by the number of sun hours we get in a day. So in our case, we need 1000Wh. 

An example we use is an average of 4 hours which could be high peak hours in the afternoon between 12 and 4. If you get more than 4 hours of sun per day, then use that number. 

1000Wh/4= 250 Watts

A 250 Watt solar panel will be enough to provide 1000Wh in the course of the day. Solar panels are not that expensive so you can even go double up to 500 Watts or five 100-watt solar panels and collect more power.  

What Size Battery do you need for the Microwave?

To find the size of the battery, you divide the watt-hours by the voltage. In the case, you have a 12-volt system, so you divide 1000Wh by 12V and for the 24V system, you divide by 24V. 

1000/12 = 83.33 Ah

1000/24= 41.66 Ah

This however does not give you the size of the battery you need but the capacity of the battery reserve that the microwave is pulling through your inverter.  So you need a battery that you can safely pull 80 amps per for the 12v system and over 40 amps per hour for the 24v system. 

A battery that can safely discharge 80 amps in an hour is a 300Ah 12v LiFePO4 battery. You can also go for a 24v 200Ah (two 100Ah) battery for the 43 amps. We specifically recommend lithium batteries as with lead acid batteries you can go up to 40 amps. Lithium batteries can be discharged up to 1C and most manufacturers recommend a 0.5C discharge. 

How Much Solar Power to Run a Microwave for 6 minutes

In our case, we are running our device for 6 minutes or 1/10^th of an hour. So to run a microwave for 6 minutes you will need 100Wh of energy. This is not a lot as compared to the 1000Wh required for the hour and looks more manageable doesn’t it? So let’s take a look at how many solar panels you’ll need. 

To run a microwave for 6 minutes, you would need about 100Wh of energy. To find the size of the battery, you divide the watt-hours by the voltage. In this case, you have a 12-volt system, so you divide 100Wh by 12V. 

This gives you 8.3333Ah to run your microwave for 6 minutes. Note that you are discharging this over an hour’s time if you not using any other load on your battery. So the battery should be around 50Ah. To ensure there is enough reserve capacity in your setup, however, it is recommended that you size the battery at least two times larger than this value: 100Ah should do the trick.

Conclusion 

A microwave is a high-wattage appliance however if you are using it for short periods of time to warm your food it actually doesn’t use that much power. Compared to other kitchen appliances a microwave will actually put less of a strain on your solar system. Low Wattage microwave will require a smaller solar system than a high-wattage appliance.