Thinking about running your kitchen, RV, or a small mini camping fridge on solar power and not sure about how many batteries or what size battery you'd need to run your fridge for 24 hours.
Keep reading, with a few simple calculation steps you can find out what size battery you'd need to run your fridge
In short, you would need about 50-400Ah of battery capacity to run a refrigerator or fridge for 24 hours. The exact value will depend on the size of your fridge, the type of battery, and its voltage
Now follow these steps to select the right size battery for your fridge
How Much Solar Power Do i Need To Run a Refrigerator?
first of all, let's calculate the solar power requirement for your fridge then we'll discuss which battery bank size will be the best suit for your refrigerator.
Solar power needed to run fridge = Average power consumption of fridge per day
On average new technology fridge (manufactured after 2010) runs for about 8 hours in 24 hours because of its duty cycle. and the old technology fridge runs for about 12 hours.
other external or internal factors will increase the compressor running time which you can decrease by watching this video
Now to calculate the power consumption of your fridge read the product description sheet in which the wattage consumption will be mentioned as "estimated yearly/monthly power consumption = value in kWh" (kWh = 1000Wh)
Watt-hour: is the total power consumption of any appliance within a specific time period
Or if there's no estimated power consumption value mentioned, you can calculate by yourself with the help of volts and amps input mentioned values
Watts = Amperes (amps) * Volts (V)
1.1*115 = 126.5Wh My medium size RV fridge consumes 12.5 watts of power in an hour when the compressor is running.
Now to calculate the total power consumption in a day multiply the value by 8 (duty time)
126.5*8 = 1012Wh or 1kWh You'd need a 1kWh of solar power to run medium size RV fridge for 24 hours
Note! i haven't mentioned the surge wattage of the fridge which is usually 3 times higher than the power consumption of your fridge because you only need to consider the surge wattage when selecting the size of an inverter.
Also, you'd need an inverter to convert the DC into AC so you can run your fridge. Which i have discussed in in-depth (link is available at the end of this article in other related posts session)
Need a simple solution? use the electric power consumption meter to find out the exact total wattage consumption of your fridge in 24 hours by simply placing this meter in between the electric power socket and the fridge plug.
- Monitor your electrical usage by day, week, month, or year
- Large LCD display counts consumption by the kilowatt-hours
What Size Battery To Run Fridge? Calculation
There are two key points to keep in mind when selecting the battery size for your fridge.
- Battery Depth of discharge limit
- Power losses
Step 1: Consider Battery Type & DoD limit
- Lithium (LiFePO4) Battery: 80-100% Depth of discharge limit
- Lead-acid Battery: 50% depth of discharge limit
- Gel Battery: 50% depth of discharge limit
- AGM Battery: 50% depth of discharge limit
Only lithium-ion or LiFePO4 type batteries can be fully discharged up to 100% but other most of the batteries have a DoD limit to maintain the battery health.
This means you can only use 50% of the capacity power from your lead acid, AGM, and Gel batteries.
Step 2: consider Power Losses
Power losses will occur in cables, and because of inverter inefficiency. which is also called DC to AC conversion power loss.
Now the inverters come in between 85-95% efficiency rate. But i'll take a 90% efficiency inverter rate as an inverter which is the most common one.
You can find out the inverter efficiency rate on the specs sheet of check online on your manufacturer's official website.
Cables losses will be between 1-5%, So to select the right gauge cable for your battery and inverter i have made this chart for you.
Pairing the right size cable with your inverter can save about 5% of power loss.
Calculation
Now first of all convert the power requirement from watt-hours to amp-hours. Because the capacity of the battery is measured in amp-hours (Ah)
Amp-hours Required = Fridge power consumption per day + Power losses/Desire battery volts (12, 24, 48v)
Confused? let's take the above medium size RV fridge as an example which uses 1kWh of power, and a 90% efficient inverter. i'm assuming that you'd use the right size cable size between your battery and inverter which in result will cause 0% power losses
For Example
1000 + 10% (90% efficient inverter) / 12v = 91Ahyou'd need about 90 amp-hours of power to run a medium size RV fridge for 24 hours
You'd need a 12v 100Ah lithium or 12v 200Ah lead-acid or AGM deep cycle battery to run a medium size RV fridge for 24 hours.
❝ Now if you're on a budget i would suggest you go with a lead-acid or AGM battery type but if the budget is not an issue for you then i would highly recommend you go for a lithium battery type which will last about 2000 life cycles before losing it's 20% capacity storage power but on the other hand lead-acid or AGM batteries will lose their 20% storage capacity in 500% cycles ❞
How Many Batteries To Run A Refrigerator? - Chart
Here's a chart on how many batteries you'd need to run any size fridge or refrigerator on solar power.
| Fridge Type | Fridge power consumption (per day) | Required 12v Lithium Battery Size |
|---|---|---|
| 12v mini camping fridge (4.5 cu. ft.) | 640wh | 50Ah |
| Medium size camping fridge (5-8 cu. ft.) | 800wh | 70Ah |
| RV fridge (10 cu. ft.) | 1 kWh | 100Ah |
| Medium size kitchen fridge (10-15 cu. ft.) | 1.3 kWh | 120Ah |
| large size kitchen fridge (18-22 cu. ft.) | 1.7 kWh | 150Ah |
| Extra large size kitchen fridge (28-30 cu. ft.) | 2.2 kWh | 200Ah |
Summary
- You'd need around 12v 50Ah lithium or a 12v 100Ah lead-acid battery to run a 12v mini camping fridge for 24 hours
- You'd need around 12v 100Ah lithium or a 12v 200Ah lead-acid battery to run an RV fridge for 24 hours
- You'd need around 12v 150Ah lithium or a 12v 300Ah lead-acid battery to run a large size kitchen fridge for 24 hours
Other Must-Read Posts
- What Size Inverter To Run A Fridge?
- Calculate What Size Solar Panel For Fridge
- How Long Will 12v Battery Run a Refrigerator? Runtime Calculator
- How Long Will A 100ah Battery Run A Fridge?
I hope this short guide was helpful to you. still, have any confusion? LEAVE A COMMENT or contact us. Thank You!
