A 200Ah Lithium Iron Phosphate (LiFePO4) battery is the perfect choice for a variety of off-grid applications. From your refrigerator to your computer you want to make sure all things are running. So can you power a microwave off a 200Ah battery?
Yes, you can. A microwave is one of the devices in your kitchen that doesn’t require as much power as other devices in your kitchen. A 200Ah battery can run your microwave for up to 28 mins with extra capacity to spare.
In this article, we take you through how we arrived at this figure and how you can use this battery to run so much more.
Microwave Power Consumption
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. This is the amount of power the battery will need to produce in order to run the microwave.
The two other metrics we’ll need are the watt-hours and amps needed.
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. The wattage tells you how much energy the appliance will use.
For example, a 100-watt light bulb running for 2 hours uses 200 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 1 Kwh.
This number will tell us how long the battery can support the microwave.
How Many Amps Does a 1000-Watt Microwave Draw?
The amps required will tell us if the battery has enough charge to run the microwave. A 1000-watt microwave will need around 8.33 amps to run when using it from the standard 120V outlet. This is the number of amps that it will be drawing from the inverter. Depending on the DC voltage of the inverter you can calculate the number of amps the microwave will be drawing through the inverter.
To find the number of amps the microwave will draw, you divide the watts by the voltage. In this 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 Amps
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.
So can our 200Ah battery support this?
How Many Amps Can a 200Ah Provide?
Amp-hour rating in batteries gives the charge in amps that can be drawn from a battery over a particular time given in hours.
A Deep Cycle Battery is intended to produce the charge for a long period of time like 20 hours. So for a 200 Ah battery, it should produce at least 10 amps over a 20-hour period.
However, you can go higher or lower depending on the appliance you are using. Deep cycle batteries are recommended to be discharged at 20% of their capacity so for a 200 Ah battery the max discharge per hour would be 40 amps meaning it can last 5 hours.
For lead acid AGM batteries this can be lower as they can only be discharged up to half their capacity meaning it’s only 100Ah of its capacity that is usable. This means it can last only 2.5 hours when discharged at 40 amps and 5 hours at 20 amps and 10 hours at 10 amps.
How many watt-hours is a 200 Ah Battery
You can use the following formula to determine how many watts can be drawn from a battery.
Watts = Volts x Amps
So if your battery is 12v and has a 200 Ah capacity, then you can draw 2400 Watts from it. This is for the full battery cycle. With the 40 amps max draw it means you can get 480 watts max per hour. You can push this to 50 amps or 600 watts per hour with LiFePO4 batteries.
How Long Will a 200Ah Battery Run a 1000-watt Microwave?
We already know the battery can support 480 watts but we need 1000 watts for the microwave to run for an hour. So how long is 480 watts?
(480/1000) = 0.48 hrs
In minutes 0.32 x 60 = 28.8 minutes
A 200Ah 12v battery will run a microwave for 28.8 minutes. This is without any other appliance drawing power from the battery. But this only draws 1000Wh from the battery. After you are through with your microwave you can add another appliance like your electric kettle for a few minutes.
Conclusion
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. A battery that can safely discharge 80 amps in an hour is a 300Ah 12v LiFePO4 battery