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Inverters have become more powerful and affordable so that now you can use it to run large appliances. But is a 2000W inverter enough to run a refrigerator? Refrigerators come in all kinds of sizes and have different specs, so in this guide we will consider all these factors. This way you can determine what inverter to use.
A 2000W inverter can run a refrigerator if its power consumption is no more than 2000 watts and the peak power is 4000 watts or less. An energy efficient 21-24 cu. ft. refrigerator uses 1200-1500 watts so the inverter can run them.
How Big of a Refrigerator Can a 2000W Inverter Run?
Inverter capacity is determined by its running and peak watt capacity. A 2000W inverter has a running watt limit of 2000 watts and a surge capacity of 4000 watts.
Here are some common refrigerator sizes and their daily power consumption. The calculations are based on an 8 hour cycle.
At a glance you can see that a 2000 watt inverter like the Renogy Pure Sine Wave can run most of these models.
Please bear in mind these figures are for general guidelines only. You should check the manufacturer’s site for more details on the actual power usage. While today’s refrigerators are more energy efficient, there are a lot of factors that affect the power consumption of these appliances.
These figures also assume the surge capacity of the refrigerator is twice that of its running power. Some models have a surge capacity of three times its normal power requirements.
|Refrigerator Size||Running Watts||Surge Watts||Inverter Size|
|14-19 cu. ft.||1000- 1160W||2320W||2000W|
|20-24 cu. ft.||1200- 1500W||3000W||2000W|
|25-27 cu. ft.||1600- 1800W||3600W||2000W|
|28-30 cu. ft.||1800- 2000W||4000W||2000-3000W|
With this inverter, it is enough to run a lot of appliances and even solar panels. However, if the fridge is 2000 watts, you cannot load any more. If you want run to other appliances along with your refrigerator, you will need a larger inverter.
How to Calculate Refrigerator Power Consumption
Refrigerator power usage is provided in amps or watts per hour. If your fridge has it listed in amps, multiply this by voltage to get its watts (amps 120V = watts).
That means if your refrigerator draws 9 amps, multiply 9 x 120 volts = 1080 watts
If the power is listed in kWh, just remember that 1kwh = 1000 watts.
A refrigerator does not run for 24 hours a day. It runs in cycles like an air conditioner. When your fridge starts it cools the temperature to the degree you specified. Then it cycles off and goes back on when the temperature starts to rise. For example, when you open the fridge door, warm air gets in so the fridge has to cool it down again.
On average a refrigerator is on for about 8 hours a day. So if your fridge consumes 150 watts an hour, multiply that by 8 hours:
150 x 8 = 1200
The refrigerator consumes 1200 running watts an hour a day.
Surge watts. The surge or peak watts is the power needed by a refrigerator to start up. This only takes less than a second, but it is usually double that the running watts.
A refrigerator listed at 1500 watts will have a surge watt requirement of 3000 watts. Inverters also have running and surge watt capacities similar to these appliances. A 2000W inverter for example usually has a 4000W surge capacity.
To keep it simple: if a refrigerator has a 2000W running watt and 4000W surge watt requirement, a 2000W inverter can run it. If the surge requirement is more than 4000 watts, you will need a larger inverter. Refrigerators run on AC so an inverter is a must for solar panels.
How Long a Can a 2000W Inverter Run a Fridge?
If your refrigerator is on electricity, the inverter can keep going as long as there is power coming in. If the inverter is running on batteries it will continue provided that there is enough power in the battery.
You need at least a 300ah battery bank to run a refrigerator that uses 1200 watts a day. Here is how we came to that number:
Let us assume you have a 20 cu ft. refrigerator that consumes 1.2 kWh a day. 1.2 kWh is 1200 watts a day.
Battery capacity is in amp hours (ah) so we need to convert watts into amps. To do this, divide the watts by the battery voltage. The most widely used are 12V batteries so we will use that.
1200 / 12 = 100
A 100ah battery has a capacity of 1200 watts. That is not enough to run your refrigerator for two reasons: the battery depth of discharge and second, the surge peak.
Remember that surge peak watts is double that of the running watts. If your fridge uses 1200 watts a day, it needs 2400 watts of surge power to run. A 100ah 12V battery only has 1200 watts so it is not enough.
So to get to 2400 watts, you need a 200ah battery or two 100ah batteries. So why did we say you should have at least 300 ah?
Because it is not a good idea to completely discharge a deep cycle battery. A 200ah lead acid battery for instance has a 50% depth of discharge (DOD) .
What this means is that you can only use 50% of the battery capacity per charge. When capacity drops to 50%, you have to recharge the battery. With a 200ah battery, you only have 100ah available for use per charge.
AGM batteries have a 70% DOD so you can keep using it until capacity drops to 30%. Lithium batteries have even better DOD, from 85 to even 100%.
Figuring out what the DOD is can be time consuming, so it is better to get a 300ah 12V battery instead. 300ah is equal to 3600 watts more than enough to power the refrigerator and not have to worry about the peak power not being enough. With 3 x 100ah 12V batteries like the Redodo LiFePO4, that should be enough.
Once you have the batteries set up, you can connect the fridge to your inverter and start using it. If you are using electricity as the power source, make sure that you have a circuit breaker for the inverter installed.
What is Inverter Efficiency and Why Does it Matter?
Inverters consume power when they run. If connected to solar panels, it converts the DC power produced by the panels into AC so that it can be used by appliances. During this process, some efficiency is lost. This can also apply to some inverter generators.
The more efficient the inverter is, the less extra power it consumes. Look for inverters with at least a 90% efficiency rating.
To illustrate: imagine you have a 20 cu. ft. refrigerator. You have two options, a 95% efficient inverter and another that has an 80% efficiency rating. To calculate inverter efficiency:
Watts / battery voltage = watts
Watts / inverter efficiency rating
If your fridge consumes 1200 watts a day and you use a 12V battery, divide the watts by the battery voltage.
1500 / 12 = 125
Now divide 125 by the inverter efficiency. If the rating is 80% divide 100 by .80:
125 / 0.80 = 156.2
Your refrigerator ends up using 156.2 watts an hour or 1249 watts a day (based on an 8 hour cycle).
If you use the inverter with a 95% efficiency rating, this is what the numbers look like:
1500 / 12 = 125
Divide this figure by .95:
125 / 0.95 = 131.5.
That is 131.5 watts an hour or 1052 watts per day on an 8 hour cycle. That is a difference of 197 watts a day or 6kWh a month.
To get the maximum value for your inverter, you should buy an energy efficient refrigerator. It will use less power than most units and save you money. Plus they will help your inverter and battery run a lot longer.