Power and Charging Guide

A guide to powering your portable fridge

When looking to purchase a new portable fridge, the other important thing to consider besides the fridge itself is a means of powering it. It’s important to note for first-time buyers that portable fridges do not power themselves.

Most fridges come with a range of power options to suit a number of different conditions and setups, and we’ll cover those here in this guide.


Powering Your Fridge

240v AC Mains Power

The simplest and most obvious means of powering your portable fridge is connecting it to a 240v AC power point, such as the power points in your home or on powered sites at a caravan park or camping ground. This provides the fridge with unlimited electricity and will keep it running happily for weeks on end. Almost all portable fridges have the ability to run on 240v power built in as standard, though be sure to check just in case, as some of the smaller sized options do not have this feature.

But what about those times when you don’t have access to mains power? That’s where these other options come into play.

12v Cigarette Lighter Socket

During transit, your portable fridge can run on 12v power; which can be provided by a battery (see below), or using your car battery via the cigarette lighter socket in your vehicle.

This is a great way to save power on your dedicated fridge battery when travelling between destinations, without the worry that the power will run out.

Just be sure not to run the fridge from your vehicle whilst the car is off for too long. This will quickly flatten your car battery, and you’re going to end up stuck.

12v Battery Power

A good quality 12v Battery pack is an essential piece of kit for those looking to take their fridge to remote locations and camp grounds that don’t have access to main power. Depending on the size of your battery, it will be able to power your fridge efficiently for several days.

So can you just use any old battery to power your fridge, like a car battery? The answer is no. Batteries come in two main varieties; Starter Batteries and Deep Cycle Batteries.

Starter Batteries are designed to deliver a large amount of power in a very short amount of time, and are the type of battery used by your vehicle. These are great for starting a car, where a lot of charge is needed quickly, but horrible for powering a fridge for an extended period of time.

Deep Cycle Batteries work in the opposite way; they’re made to deliver a small trickle of power over a long period of time – just what you need to power something like a portable fridge.

The next thing to look at is size. Batteries are measured in Amp Hours (Ah). Basically, the higher the Ah, the longer the battery will last. Simple enough, right? The key thing to remember when looking at Ah size, though, is that a battery will not fully drain down to 0%. Effectively, most batteries will go down to about 50% charge before becoming “flat” – pushing it much further than this can damage the battery permanently.

What does this mean for the Ah measurement? It means that you should halve the number to roughly gauge the effectiveness of the battery. So a 100Ah battery is likely to only deliver 50Ah, as an example. It’s for this reason that we recommend always buying the biggest Ah battery you can, with 120Ah being our firm favourite.

Without getting too technical*, a good 120Ah battery will power a 40L fridge for about 2 days or so, without any problems. Smaller fridges can expect to get about 3 or 4 days, whilst larger fridges may get around 24 hours.

Another good option for using a battery is to invest in a Battery Pack, or a “Battery Box”, which handles all the heavy lifting and technical side of things for you, and gives you much more versatility and ease of use when running your fridge on battery power. Most also have a built-in Smart Charger, but we’ll talk more about that in a moment.

Remember that if using a battery for power, you’ll also need some way of recharging that battery, but we’ll get to that shortly.

*120Ah/2 = 60Ah. A standard 40L fridge uses approximately 1Ah/hr (on average), or 24Ah/24hrs. 60Ah/24Ah = 2.5 days of power.

A standard 80L fridge uses approximately 2Ah/hr (on average), or 48Ah/24hrs. 60Ah/48Ah = 1.25 days of power.

Generator

Likewise, a small, portable generator with either 240v or 12v power outlets will quite happily keep your portable fridge powered for as long as your generator lasts, and can likewise double as a source for recharging your battery.

For a more in-depth guide on choosing a quality generator, see our Generator Buyer’s Guide.


Charging Your Battery

So you’ve got your fridge, you’ve got your battery and battery pack, what’s next? The last thing you’ll need is some means of recharging your battery, and for this, you have a few options.

The standard method for recharging a battery is known as ‘Direct Charging’, or ‘Trickle Charging’. This involves connecting your battery directly to some sort of power source (such as the ones outlined below), and will deliver a constant stream of power through to your battery. However, this is also the most inefficient means of recharging your battery, and can even be potentially damaging.

For starters, delivering a constant stream of power takes an incredibly long time to charge the battery. Next, it will also never completely fill a battery to 100% charge, usually coming up at around 80%. Lastly, direct charging means the power will continue to stream into your battery, even after it’s reached its maximum level, unless you manually turn it off. Continuing to charge a full battery will damage it if left for too long.

The other option is ‘Smart Charging’. By placing a Smart Charger between your battery and the power source, the charger will use an efficient 3 stage process to charge your battery, delivering a full charge in a far shorter amount of time than direct charging. Smart charging will also recharge your battery right up to 100%, and when it reaches that point, it will automatically shut off, so there’s no chance of causing damage from overcharging. Most Battery Packs/Boxes come with a Smart Charging system built in as standard, or you can purchase one as a separate unit.

It’s important to note that you do not actually have to disconnect your battery from your portable fridge while recharging, meaning your fridge will stay powered right throughout the charging process.

240v AC Mains Power

Just like your portable fridge, most batteries will be able to be connected to a main power point via a battery charger. If you’ve got a Battery Pack/Box, even better, as it also doubles as a charger for your battery when connected to main power via an AC adaptor.

But, just as with your fridge, you’re not always going to have access to main power. That’s the reason for having the battery in the first place after all, right? So let’s take a look at some of our other options.

Solar Power

Here in our Aussie conditions, one of the most popular methods for charging your battery on the road are portable solar panels. They’re light, easy to transport, and can easily recharge your battery in a matter of hours. When purchasing a Solar Panel Kit, they also come with a ‘regulator’ unit, which converts that solar power into energy usable by your battery. When your battery starts to run low, simply put your solar panels out in the sun, plug them into your battery pack, and let the sunshine do the rest.

Solar panels are measured in Watts (W), and as with batteries, bigger is better. We recommend using a 120W Solar Panel Kit, which should charge your 120Ah battery back to full in about 3 to 4 hours each day under normal conditions running a standard 40L fridge.

But what about those times when the weather is against you?

Generator

A good portable generator can not only power your portable fridge, but can recharge your battery as well, via a built-in 12v socket. Just start it up, plug in your Battery Pack, and it’ll do the rest.

For a more in-depth guide on choosing a quality generator, see our Generator Buyer’s Guide.

12v Cigarette Lighter Socket

Lastly, your battery pack can also be plugged directly into your vehicle’s cigarette lighter socket, just like your portable fridge. This will recharge the battery from the car’s alternator while you’re travelling between stops. Using a Battery Pack/Box will also ensure your vehicle’s battery will never be discharged completely.


Power Setup Options

Getting the power setup right for your fridge doesn’t need to be complicated. It just depends on:

  • How long you need to run the fridge
  • Time spent driving vs camping
  • How much you want to spend!

We're going to divide this into multiple “levels”, each more sophisticated than the next.

Level

Setup

(Vehicle / Trailer)

Description

Parts

Pros

Cons

Scenarios

Days of Use

Popularity

FRIDGE ONLY

FO1

Bare Bones

V Just the fridge. Plug into the cigarette lighter socket in your vehicle. When the vehicle’s engine is turned off, the fridge stops running. Like an esky, they will keep things cold for ½ to a full day, depending on how much you open it.
  • Fridge
Simple Limited use once vehicle is off. Shopping / Town Run. On-road reps. < 1 day HIGH
FO2

Constant 12V

V As above, but the cigarette lighter socket continues to power the fridge when the vehicle is turned off. Some vehicles have this option.
  • Fridge – get one with a low battery cut-out feature on it, so it doesn’t drain your starter battery.
Extends running time by a few hours. Fridge will cut-out a few hours after vehicle is stopped, but before the starter battery is flattened.

Fridges without low battery cut-outs will flatten your starter battery.

Overnight stops. 1 day

DUAL BATTERY

DB1
Standalone Aux Battery
V/T Connect fridge to an auxillary 12v battery to run the fridge when the vehicle is stopped.

Charge battery at home prior to use.

  • Fridge
  • Battery Pack
  • Mains power battery charger
Greatly extended running time. Once battery is flat, no power available. Short camps. 2 days

Before mains power required

DB2

Aux Battery with Vehicle Charge

V/T Auxillary battery receives direct charge from vehicle while vehicle is running – e.g. via Andersen plug
  • Fridge
  • Battery Pack
  • Cable (e.g. Andersen plug)
Battery able to be recharged.

Ongoing power available

Limited charge capacity for deep cycle batteries (80% SOC[1]).

Need to run vehicle every couple of days (e.g. full days driving).

Touring, with regular vehicle usage.

Need Andersen plug fitting near aux battery.

2 days

Before needing vehicle run

DB3

Aux Battery with Isolator charge

V Auxillary battery receives charge via battery isolator. Fridge uses power from both starter and auxillary battery without risk of flattening starter battery.
  • Fridge
  • Battery Pack
  • Dual Battery Isolator
Battery able to be recharged.

More capacity available as starter battery used too.

As above, but need to run vehicle slightly less often Touring, with regular vehicle usage.

Need Isolator kit installed. (DIY available).

2-3 days

Before needing vehicle run.

HIGH
DB4
Trailer mounted Aux Battery with DC-DC charger
T If auxillary battery is mounted on trailer, a DC-DC charger can overcome voltage drop due to long cable runs.
  • Fridge
  • Battery Pack
  • DC-DC Charger
Trailer mounted battery charged to a higher capacity. Camp trailers 2-3 days

Before needing vehicle run.

HIGH
 

SOLAR

DBS1

Aux battery + foldout solar

V/T DB1 + Solar

Fold out solar panels charge auxillary battery

  • Fridge
  • Battery Pack
  • Folding solar panel kit
Recharges battery when stopped Needs 5+ hrs of sun / day

Security of solar panel

Doesn’t charge while driving

Any touring / camping. Unlimited

With sun & driving

DBS2

Aux battery + solar + Isolator

V/T DB3 + Solar

Isolator installed in vehicle for charging while on-the-move.

Fold out solar panel kit for charging when not.

  • Fridge
  • Battery Pack
  • Dual battery isolator
  • Folding Solar panel kit
Recharges battery while driving + camped Needs 5+ hrs of sun / day when camped.

Security of solar panel.

Any touring / camping. Unlimited

With sun & driving

HIGH
 

GENERATOR

DBG1

Aux battery + generator

V/T DB1 + Generator

Generator charges auxillary battery

  • Fridge
  • Battery Pack
  • Generator
Recharges battery while camped.

Generator can provide 240V for other appliances.

Needs fuel for generator.

Generator noise.

Security of generator

Doesn’t charge while driving

Any touring / camping. Unlimited

With fuel.

DBG2

Aux battery + isolator +  generator

V DB3 + Generator

Isolator installed in vehicle for charging while on-the-move.

Generator for charging when not.

  • Fridge
  • Battery Pack
  • Generator
Recharges battery while driving + camped.

Needs less time to recharge battery than solar panel setup.

Needs fuel for generator.

Generator noise.

Security of generator.

Any touring / camping. Unlimited

With fuel.

HIGH
DBG3

Aux battery + DC-DC charger +  generator

T DB4 + Generator

DC-DC charger for recharging trailer battery while on the move.

Generator for recharging trailer battery while camped.

  • Fridge
  • Battery Pack
  • Generator
  • DC-DC Charger
Recharges battery while driving + camped.

Needs less time to recharge battery than solar panel setup.

Needs fuel for generator.

Generator noise.

Security of generator.

Any touring / camping. Unlimited

With fuel.

HIGH
 

SOLAR + GENERATOR

DBSG V/T Any of the solar options with the addition of a generator in case there is no sun for extended periods. Covers all bases Lots of gear! Any touring / camping. Unlimited
 

[1]Charging a deep cycle battery by connecting directly to vehicle charge line is difficult to achieve above 80% state of charge (SOC) in auxillary battery. This is due to the different charging process required for deep cycle AGM and Gel batteries commonly used.  Note, that a deep cycle battery is considered flat at 50% SOC, therefore, this only give you 30% usable capacity of your battery – ie 30 amp hours in a 100Ah battery.


Video

What is a Smart Battery Charger?

Engel Smart Battery Box

 


So there you have it, everything you need to know about powering your new portable fridge. Be sure to visit our online store to browse the entire range of power and charging options.