There’s nothing better than pulling up at camp, setting up for the night, and grabbing a cold drink after a long day on the road. But if your setup isn’t right, that dream can quickly turn into a headache. Not only could your fridge switch off and warm up, but you might also find your starter battery flat and your vehicle refusing to turn over.
So, what’s the best way to run a portable fridge in your vehicle without killing your battery?
STARTER BATTERY VS DUAL BATTERY
There are two ways to power your fridge: directly from your vehicle’s starter battery, or from a dedicated auxiliary battery.
While plugging into the starter battery might work while the engine is running, as soon as you switch off, your fridge will keep drawing power. Leave it too long, and you’ll flatten the battery you rely on to get moving again.
The smarter option is to set up a dual battery system, where a second battery is dedicated to running your fridge and other accessories. This way, your starter battery stays protected and you’re free to head off-grid with peace of mind. If you want real freedom and the ability to head off-grid for days without worrying whether the car will start, you’re going to want to run your fridge from a dedicated dual battery system.
UNDERSTANDING FRIDGE POWER DRAW
To choose the right battery for your setup, you’ll need to know how much power your fridge will consume.
A typical 60 litre camping fridge will draw about 5 amps while the compressor is running. However, a fridge does not run continuously but instead cycles on and off to maintain the desired temperature. With the compressor running on average 30% of the time, or for 20 minutes in the hour, our 60-litre camping fridge is drawing on average 2 amps. Consider this over a 24hr period, your fridge will consume around 48Ah. This is a good estimate not accounting for variables such as fridge setting and ambient temperature.
Here’s a quick guide to average fridge sizes and their power needs:
| FRIDGE SIZE | AVERAGE CURRENT DRAW | 3-DAY AH DRAW | RECOMMENDED LITHIUM BATTERY |
| 35-45L | 1.5A | 108Ah | 120Ah Lithium |
| 50-65L | 2A | 144Ah | 150Ah Lithium |
| 80L+ | 3A | 216Ah | 250Ah Lithium |
CHARGING WHILE YOU DRIVE
If you’re on the move most days, recharging your auxiliary battery while driving is the simplest way to keep things topped up. A REDARC BCDC In-vehicle DC-DC Charger draws power from your vehicle’s alternator and delivers the correct charge profile to your secondary battery.
Pairing it with a REDARC Smart Battery Monitor gives you full visibility of your system, so you’ll always know how much power is left in reserve.
STAYING LONGER WITH SOLAR
For longer trips where you’re parked up at camp, solar is the easiest way to extend your fridge runtime. Adding a REDARC Solar Blanket or Fixed Solar Panel means your battery will recharge during daylight hours, keeping the fridge running through the hottest summer days.
A 120W solar panel is a great starting point to pair with a fridge, ensuring your battery stays topped up for days on end.
READY FOR COLD DRINKS ANYWHERE
From quick weekends away to extended off-grid adventures, having the right dual battery system makes all the difference. With a dedicated auxiliary battery, a quality DC-DC charger, and solar to keep things topped up, you’ll never have to worry about warm food or a flat starter battery again.
Want to see it all explained step by step? Watch our video guide below to learn how to keep your portable fridge powered anywhere you travel.
