12V fridges or freesers are designed to how low energy consumption. In fact, a 12V battery can supply electricity to run a 12V fridge.
To power, the fridge/freezer, connect the 12V battery to the fridge using a DC power cord (for the large-capacity fridges) or plug it into a car’s cigarette lighter socket.
Note: The fridge can only work properly if the battery has a high enough voltage (usually 11.8V and above).
Should your fridge/freezer fail to work or not work properly, confirm that your battery has sufficient charge by measuring the battery voltage.
How various battery types compare when powering a 12V fridge/freezer
You can connect your fridge to a deep cycle AGM, Flooded Lead Acid battery, or Lithium battery.
Whenever possible connect to a Lithium battery type: they are lighter and therefore are used more in rechargeable portable fridges/freezers.
Lithium batteries also have more usable capacity than both AGM and flooded Lead Acid batteries (FLA) though they cost more than either battery type.
AGM batteries are also a good option: they are more affordable than lithium battery types and have a reasonable recommended depth of discharge (recommended 50%).
Table: Comparison table of the Pros and Cons of AGM, Lithium and Flooded Lead Acid batteries
|AGM||– Generally cost less than Lithium batteries|
– Spill proof
|-Should only be discharged to 50% of their capacity for good battery life|
|Lithium||– Generally last longer compared to AGM or Flooded Lead Acid batteries|
– Take up less physical space and weigh less
– Have more usable capacity and can be discharged to 80% of their capacity without significant reduction in battery life
|-More expensive compared to AGM or Flooded Lead Acid batteries|
|Flooded Lead Acid (FLA)||Cost less compared to AGM or Lithium batteries||Prone to spills Need to be installed in a place with good air circulation|
Recommended battery types for 12V fridge/freezer
Compared to car starter batteries, deep cycle AGM, Lithium, or FLAs are better suited to powering appliances such as fridges that draw power over several hours.
Whereas car starter batteries can also power fridges, they are better suited to providing high startup currents for a short time for best performance and can fail prematurely when drained considerably repeatedly.
Can you power your 12V fridge/freezer using a 100Ah battery
You can power a 12V fridge using energy from a 12V, 100Ah battery, or any other battery capacity provided that it is sufficiently charged matches the fridge voltage (12V or 24V), and is sufficiently sized not to be deeply discharged to affect its lifespan.
How long a 100Ah battery runs a 12V fridge/freezer
A 100Ah AGM battery can power a 12V fridge for 20 – 40 hours a day depending on the fridge’s actual power consumption.
The battery runtime provided above assumes a 12V fridge that consumes up to 1kWh per day, typical of fridges with power consumption between 45W-90W.
Lithium batteries have the more usable capacity and therefore a 12V fridge runs longer with an estimated runtime of 32 – 64hrs with a 100Ah LiFePO4 battery.
What size of battery for a 12V fridge/Freezer
Besides the 100Ah battery, you can use 200Ah, 50Ah AGM, and Lithium batteries to run your fridge.
Note that the actual runtime changes according to the battery capacity.
Table showing indicative runtimes for 12V fridge with 50ah, 100Ah, 200Ah*
|AGM||10 – 20 hours||20 – 40 hours||40 – 80 hours|
|Lithium||16 – 32 hours||32 – 64 hours||64 -128 hours|
How to maximize how long your 12V fridge/freezer runs on battery
Besides the fridge’s actual power consumption and the battery capacity, here are some of my top tips to getting as much runtime from your battery as possible:
- When outdoors, keep the fridge/ freezer in a shaded area
- Whenever possible, chill drinks or foods the night before. This reduces the fridge’s energy consumption as its compressor does not have to work as hard to keep them cold.
- Disconnect the fridge’s battery or switch it off when the fridge is not in use. This eliminates energy draw on the battery when on standby.
How many batteries are needed to run a 12V fridge/freezer?
You can use 1 pc 12V 100Ah AGM battery, or 2 pcs 50Ah batteries to run your 12V fridge for approximately 20-40 hours depending on your fridge’s actual power consumption.
If you need your fridge to run for say 10 hours, you can use a smaller size battery.
1 pc 12V 50Ah AGM battery can power your 12V fridge for about 10 – 20 hours.
In addition to the actual power consumption, the number of batteries you need to power your fridge depends on how long you plan to run your fridge each day.
For example, you can double your fridge’s run-time to about 40-80 hours, by connecting it to 2 pcs of 100Ah battery in parallel or 4 pieces of 50Ah battery AGM battery.
Note: The above runtime estimates assume a fridge or freezer with daily consumption of less than 1kWh (<90W)
Electrical setup for powering a 12V fridge on batteries
The battery is only part of the electrical setup you need to run your 12V fridge reliably.
To provide your fridge/freezer with electricity you can use the car’s electrical system, a solar system, or grid power (Yes, some fridges can be powered by both 12V and 110V!)
Using your car’s electrical system
You can power small 12V fridges (65 -90W) using the car’s electrical system by plugging them into the cigarette lighter.
Beware though that the fridge can drain your car’s battery.
To prevent your battery from running flat, keep your car’s engine is running when the fridge is plugged in.
Note: Some portable fridges/freezers have a low voltage disconnect or battery saver system that switches of the battery when its voltage is getting dangerously low to prevent your car’s battery from being drained flat.
Make sure this feature is activated.
An example of a solar system set up to power your 12V fridge with consumption of under 1kWh per day and powers your fridge for about 10 hours
- 50Ah AGM battery
- 100W solar panel
- 20-30A charge controller
or a 105W solar panel only in case the fridge/freezer has a 50Ah AGM or 15Ah Lithium inbuilt battery
What size solar panel do you need to run a fridge/freezer?
The solar panel size needed to run your fridge depends on the fridge’s power consumption and intended duration of operation during the day.
The table below shows indicative solar panel capacities (w) to use with 12V fridges. Note, this is a guide, consult your fridge/freezer manufacturer for guidance.
|No||Fridge/ freezer power consumption (watts)||Estimated solar panel capacity (watts)|