WHAT DO PORTABLE FRIDGES NEED TO RUN?

You fridge uses electricity; 240V, 24V or 12V, and the laws of thermodynamics to move heat from the inside of your fridge where the food is, to the outside air.

I DON'T SEE ANY THERMODYNAMICS LAWYERS INSIDE MY FRIDGE; WHAT ARE YOU TALKING ABOUT?

Simple really. Heat on its own always flows from hot to cold. It will continue to do this until the temperature equalises. This is what happens in an icebox - heat flows from your drinks to the ice: the drinks get cool, the ice melts, and eventually it all ends up at the same temperature.

SO HOW DO PORTABLE FRIDGES KEEP THINGS COOL?

In an icebox, you remove the coolant (the melted ice) which has absorbed the heat, and you refill it with fresh ice. In a refrigerator, you use a refrigerant to absorb the heat from the food, and then you pump it using a compressor away from the food and replace it with fresh refrigerant to keep the contents cold.

WHY DO PORTABLE FRIDGES KEEP RUNNING ONCE EVERYTHING IS COLD?

It's about insulation. Because the contents are colder than the surroundings, heat will flow from the surroundings and through the walls into that cold space. Insulation slows down that heat transfer, but it can't stop it. And every time you open the llid, add some contents, heat gets in too. Better fridges and iceboxes have better quality insulation and seals.

WHAT IS A REFRIGERANT?

A refrigerant is usually a gas or a liquid that requires a lot heat energy to freeze, condense or evaporate; that's what makes it useful. Ice is a refrigerant but it's hard to pump around in pipes - it's better to use a gas that condenses to a liquid at a temperature lower than what you want the fridge to work at. Car air conditioners and portable electric fridges usually use R134A which is much less damaging to the atmosphere than previous refrigerants such as R12 {Freon}.

HOW DO PORTABLE FRIDGES WORK?

If you look at the below diagram, you will see that heat flows from the food to the refrigerant in the coils of the evaporator.
Some of the refrigerant evaporates, which stores the heat in the refrigerant gas. This is similar to what happens when you sweat on a hot day and the evaporation of sweat from your skin carries your body heat away. The compressor sucks the warmed refrigerant from the evaporator and pumps it through to the other side at high pressure.
If you have ever pumped a bike tyre with a hand pump vigorously, you will know that increasing the pressure raises the temperature of the air inside and the bike pump gets hot. The refrigerant, which is now hotter than the outside temperature, flows through the condenser, where the hot vapour at high pressure gives off its heat, assisted by a fan.
The refrigerant has now cooled, but is still at the high pressure pumped by the compressor. It now has to flow through an accumulator and a capillary tube, which is a small tube that serves to drop the pressure down before it goes back to the evaporator. Expanding a gas or dropping its pressure causes it to cool further, so we now have cold refrigerant ready to circulate through the system again.

HOW DOES MY REFRIGERATOR PERFORM ON HOT DAYS?

Your refrigerator has to work harder on a hot day. Because it's hotter outside the insulation lets more heat through, and the condensor has to work harder to try and get rid of the heat into air that is already hot. This is also true for your fridge at home. The compressor will run more often and you will use more power. It is really important to keep the fridge out of the direct sun, and not in a heated environment like the back of a closed up car or 4WD.

I DON'T SEE AN EVAPORATOR PLATE, WHERE IS IT?

It is hidden behind the stainless steel liner near the top of the large compartment. This protects it from accidental damage such as over-enthusiastic defrosting. It's the cold ring you can feel near the top

DOES IT MATTER IF LIQUID SPILLS OR COLLECTS INSIDE PORTABLE FRIDGES?

Whilst the stainless steel liner is sealed, if by chance any moisture did seep into the insulation the fridge performance would be noticeably affected. It is therefore highly recommended to keep the inside dry. If you wish to add extra cooling blocks into the inside of the fridge it is recommended that you use Techni-Ice sheets or sealed icepacks; never loose ice.

CAN DUST AFFECT THE PERFORMANCE OF PORTABLE FRIDGES?

Yes. Although the fridges are tough and used Australia-wide, operating the fridge in very dusty environments can lead to reduced performance as the dust collects on the condenser coils. The same is true for your kitchen fridge. Extremely dusty environments may cause poor power connections and intermittent operation so it is strongly advised not to operate the fridge in areas such as plastering, concrete sawing, landscaping or dusty outdoor conditions

PORTABLE FRIDGES TAKE A LONG TIME TO FREEZE ITEMS, IS THIS NORMAL?

Yes it is. Let's take a medium size juice bottle, e.g. one that holds 2.4 litres. On the GNA-60 sticker is says it takes 24 hours to freeze 2.5Kg (or litres) of water. It actually takes 80 times more energy to freeze water than it does to simply cool it by 1ºC.
Put another way, it takes the same amount of time and energy to cool an amount of water from 80ºC to 0ºC, as it does to completely freeze that amount of water at 0ºC. It's much better to freeze your items beforehand, and then put them in an empty fridge that is already at -18ºC. (And now you know why ice is used to keep things cool!)

HOW MUCH POWER DO PORTABLE FRIDGES USE?

When it is actively cooling it can use up to 60 - 70 Watts of power. When it has reached the set temperature and the compressor turns off, it uses less than a watt of power. Once the set temperature has been reached the average power use is usually about a third of the maximum; typically about 20 Watts overall.

CAN PORTABLE FRIDGES BE OPERATED FROM 12V DC POWER SOCKET OF A CAR?

Yes, but almost all cars will only supply 12V while the accessories are switched on or the ignition is on and/or the car is running. So if you stop and turn off the car the fridge will probability stop working too. This will help to prevent you from flattening your car battery, of course. If your car battery is not in good condition the low voltage error protection may switch off the fridge just when you are stopped, especially if it is at night and the car headlights are running too.

WHAT IS THE RECOMMENDED TEMPERATURE TO RUN PORTABLE FRIDGES AS REFRIGERATORS?

Most vegetables & fruit should be kept at a maximum temperature of 10ºC, and for milk, dairy and other perishables 4ºC or lower is recommended. Please check the guidelines printed on the packaging of food that you purchase. Below 4ºC water starts to expand and it breaks open the plant cells, particularly in high water content foods such as lettuce, strawberries, etc. It is recommended that you do not place these items close to the top of the stainless steel liner where the evaporator coils are.

WHAT IS THE RECOMMENDED TEMPERATURE TO RUN PORTABLE FRIDGES AS A FREEZERS?

If you use the fridge for carrying or transporting food that is already properly frozen, setting an operating temperature of -18ºC will meet food handling guidelines for the frozen foodstuffs. As the operating conditions of a portable car fridge will vary so much, it is not recommended to use it for long term storage of frozen food. Any foodstuffs that thaw should not be refrozen, but either used or disposed of properly. Please use your common sense.

WHY DO PORTABLE FRIDGES TAKE 3 MINUTES TO START?

When the fridge turns off there is still high pressure refrigerant in the condenser. If the compressor tried to start straight away the load would be too high. The startup delay allows the pressures in the system to equalise so the compressor uses less power to start again. It also protects the system when it is first turned on in case the unit has not been sitting level.

WHAT DOES THE 3 POSITION BATTERY PROTECTION SWITCH DO?

The BPF switch is there for battery operation only - the external power supply gives sufficient power so that the switch position does not matter. The switch is there to ensure that you don't over-discharge your battery. As there are many different sizes and types of batteries available, and the battery wire connections may vary, the BPF gives the user the choice of when to cut off the fridge to stop over-draining the battery. The standard position for the switch is to leave it in the "3" position.

THE TEMPERATURE INDICATION SOMETIMES JUMPS UP AND DOWN OR CHANGES WHEN THE FRIDGE SWITCHES OFF AND ON - IS THIS NORMAL?

The digital temperature display may vary a degree or two or as the unit is cooling down. It does not affect the operation of the fridge

CAN PORTABLE FRIDGES BE OPERATED OFF A 12V BATTERY?

Yes you can, but there are a number of factors to keep in mind to do this successfully. First of all, you need to think through how much time the battery will need to run the fridge on its own, and how you will recharge the battery to replace the energy the fridge uses.

HOW MUCH POWER DO PORTABLE FRIDGES USE IN 24 HOURS?

(1) If the fridge is trying to cool down and runs continuously, it can consume 60Watts x 24 hours = 1.44Kw
(2) If the fridge has reached temperature and is not opened, or in the sun, or a hot environment, it may only consume 20Watts x 24hours = 480W The actual consumption will be somewhere between these figures

THOSE WATT FIGURES DON'T MEAN A LOT TO ME, CAN YOU EXPLAIN IT FURTHER?

Think of the fridge as the same as one average lowbeam headlight on a car. So if we take two headlights and leave them on, that will be twice the power of a car fridge, so it should last half the time. Think about this: would your car battery keep your headlights running for 12 hours? That's what running your fridge at full power for a day is equivalent to.

CAN PORTABLE FRIDGES BE RUN SAFELY FROM THE CAR POWER SOCKET?

Yes, but not for any length of time if the car engine isn't running to top up the battery. The is where the battery protection switch becomes important - setting it to the "1" position instead of "3" will switch off the fridge before the car battery discharges too much and is safer. As the car wiring is often not thick enough, you may have to run the fridge with the switch in the "3" position anyway. If you have more than one auxiliary power socket, use the one closest to the front of the car where the battery is as there will be less voltage drop from the front socket.

MY CAR FRIDGE SWITCHES OFF WHEN I TURN OFF THE CAR AND REMOVE THE KEYS?

This is normal for most car wiring. Unless your power socket is specially wired by an auto electrician, you will need to have your ignition switch on Accessories to power the fridge.

CAN I RUN THE FRIDGE FROM A SECOND BATTERY BUT STILL CHARGE IT FROM MY CAR?

Yes, you can. An auto electrician or electronics technician can install a manual or an automatic switch that will charge an auxiliary battery when the car is running, but can be manually or automatically disconnected from the car so that it only runs the car fridge. That way you do not risk accidentally flattening your main car starting battery. You will need to safely mount the auxiliary battery and wire it correctly with fuse protection.

WHAT TYPE OF BATTERY DO I NEED?

For safety reasons, it is recommended to use a spill-proof sealed lead-acid battery [SLA]. There are a range of types, including Sealed, Gel and AGM {Absorbed Glass Mat}. A normal car starting battery is not recommended as it is designed to apply power in short bursts to start the car, not long term power which is what you need to run the fridge. A quality battery will be heavy (thicker plates), not cheap, but will power your fridge reliably. AGM type SLA batteries are superior to Gel SLA batteries, but may be more expensive, however a larger capacity Gel type may work as well as an AGM SLA battery. Gel SLA batteries cannot be charged as quickly as other types of batteries of the same capacity.

WHAT SIZE BATTERY SHOULD I GET?

Assuming that the fridge is already at set temperature, at a minimum of 480 Watts over 24 hours, you would need a 40AH (40 Amp Hours) battery. 40A{amps) x 12V{volts} = 480 Watts. For the longest life, it is advisable to only use a lead acid battery down to 50% of its capacity, so an 80AH battery would be a better choice for long term reliability, though more expensive.

I WILL BE TRAVELLING DURING THE DAY AND CHARGING THE AUXILIARY BATTERY AND RUNNING THE FRIDGE. CAN I USE A SMALLER BATTERY?

Yes you can, but you run the risk that the battery you can afford will not have the sustained capacity you need, and so some time during operation the battery voltage drops below the trigger point and the fridge will turn off. A 40AH battery is the minimum size one should consider using, and a 60, 80 or 100 AH battery will give you less problems.

WHAT SORT OF WIRE SHOULD I CONNECT THE BATTERY WITH?

You need heavy duty figure 8 DC power cable. See the attached table for information on recommended copper wire sizes between the battery terminals and the power socket on the fridge. A cable with a DC power socket on the end, and attachments to the battery terminals with a protective fuse close to the positive battery terminal at the other is required. You can then plug in the DC lead supplied with the fridge to this adaptor cable.
AWG GAUGE
SIZE
CROSS
SECTION
AREA  mm²
 
MAX LENGTH
     12V
 
MAX LENGTH
     24V
16 AWG
   1.3 mm²
    1.5m
    3m
14 AWG
   2.1 mm²
       2m
    4m
12 AWG
   3.3 mm²
    3.5m
    7m
 
   4.0 mm²
       4m
    8m
10 AWG
   5.3 mm²
    5.5m
  11m
 8 AWG
   8.3 mm²
    8.5m
  17m
Wire Dimensions - DC Power lead from battery to fridge
Note: 12V batteries can cause fires if wires get shorted together. ALWAYS have fuse protection in place.

CAN SOLAR PANELS BE USED WITH PORTABLE FRIDGES?

The car fridge will not work properly if directly connected to solar panels, as the voltage output fluctuates too much for the controller built in the fridge. You can, however, connect solar panels through a charger/regulator to a 12V battery running the fridge. The requirements for heavy duty wiring between the battery and the fridge are the same as recommended for battery only operation.

WHAT SIZE BATTERY AND SOLAR PANELS WILL I NEED?

You should plan for stormy weather, so can you run your fridge if the sun is behind clouds all day? This really means that the battery size for solar shouldn't be less than what you would get if you just planned on a stand-alone auxiliary battery: 40AH minimum, 80 - 100AH recommended. The advantage of solar will be that if the panels are large enough and the sun is shining, you can get enough power to run the panels and charge the battery, so that the fridge can run off the battery overnight

HOW DO I GET THE RIGHT SIZE PANELS?

Statistics from domestic PV (photovoltaic) installations show that the average power produced over a year is about 4 times the panel rating, up to 7 times in summer and down to 1.5 times in winter. Portable solar panels are not as efficient as rooftop units. Using the guideline from the battery section that one needs 480Watts per day to keep the fridge at a set temperature, then at an average of 4 times the panel rating, you will need a 120 Watt (folding) panel and charger. By the way, this is the common minimum size panel installed with a lot of RV campervans.

I HAVE AN 80 WATT FOLDING SOLAR PANEL, CAN I USE THIS?

Yes, but you may find that if weather conditions are not optimum for solar, your battery will eventually run down as it's just not quite big enough to run the fridge and charge the battery. You may have to plug the fridge into 240V overnight, or top up your 12V battery from the car or other charging source.

TROUBLESHOOTING

The Techni-Ice car fridges are extremely rugged and reliable and should give many years of satisfactory service (just like your home refrigerator) but if your fridge does not appear to be working correctly, there are some simple steps you can take to check its operation.

NO POWER - THE DISPLAY DOES NOT LIGHT UP.

Plug the fridge into AC power with the AC power adaptor and DC power lead. On later models the DC power plug has a red light to indicate power is being supplied. Make sure the power switch on the car fridge is in the ON position. If the Red LED on the DC power socket is lit, and the DC connector is firmly plugged into the fridge, but the display does not light up, return the fridge for repair or warranty service

NO POWER - NO DISPLAY - NO LED ON DC PLUG.

If your fridge is an earlier model with the long DC power plug, or you have the later model DC power plug with the Red LED indicator and it does not light up, you may need to check the fuse.

HOW DO I CHECK THE FUSE?

On the earlier DC power plugs the chrome ring on the nose unscrews, revealing the 3AG fuse type (spring loaded) behind it. Visually check the fuse for breaks - just in case, replace the fuse with another one as sometimes corrosion can cause the fuse to fail even though it appears OK On the later DC power plugs with the Red LED you will need to use a philips head screwdriver to undo the body. When you carefully separate the halves you can see the fuse (a smaller M205 type).

WHAT SIZE FUSE DO PORTABLE FRIDGES TAKE?

The fridges are supplied with an 8A (8 Amp) fuse which is not a common size. If you have no more spares it is safe to replace it with a 10A fuse. However, if the fuse keep on failing and you are using an original DC power cable in good condition (not joined or modified) then there may be a fault with the fridge and you should return it, with its DC power cable and power supply for repair or warranty service.

POWER - PORTABLE FRIDGES THAT DO NOT START OR START AFTER 3 MINUTES

Check the temperature setting - the fridge will not start if it is already cool enough. The fridge always waits about three minutes after power is applied before it turns on the compressor and the fan.

POWER - PORTABLE FRIDGES THAT DO NOT START - ERROR LIGHT FLASHES THREE TIMES

Compressor motor is overloaded. If the fridge has been out of level, leave it sit flat to settle for a couple of hours and retry. If the error light flashes 3 times again, return the fridge for repair or warranty service

POWER - PORTABLE FRIDGES THAT TURN OFF WHILE RUNNING - ERROR LIGHT FLASHES THREE TIMES

The fridge may have overheated from being in the sun or an extremely hot environment. Allow it to cool and check again. If the error light flashes 3 times again, return the fridge for repair or warranty service

POWER - THE ERROR LIGHT FLASHES TWO TIMES - FRIDGE MAY BE RUNNING OR MAY NOT START

A problem with the fan has been detected. Return the fridge for repair or warranty service

POWER - PORTABLE FRIDGES THAT RUN BUT MAY NOT BE PERFORMING WELL OR DO NOT COOL BELOW -12ºC

Check to see if you can feel airflow from the fan through the unit. You can also shine a torch to see if the fan blades are turning. If the fan has failed return the fridge for repair or warranty service

POWER - PORTABLE FRIDGES THAT DO NOT START - ERROR LIGHT FLASHES ONCE - AC ADAPTOR

There is insufficient power to start the fridge. Replace the fuse, even if it looks OK

POWER - PORTABLE FRIDGES THAT DO NOT START - ERROR LIGHT FLASHES ONCE - DC SOCKET IN CAR

There is insufficient power to start the fridge. Check with AC Adaptor as above. If it starts OK with the AC adaptor, but will not run from the car, you have a problem with the DC power socket, the car battery and or the wiring in the car. 
(a) Car wiring to DC power sockets is not always heavy duty; with the battery protection switch in the "3" position try it again with the car running as the car alternator will raise the voltage. If this corrects the problem you may need to get an auto electrician to replace the wire to the DC socket with heavier duty wire.
(b) If you have had problems with starting and the car lights dull quite a lot when idling, then you may be in need of a new car battery, and this may correct your DC power problems to the fridge.
(c) Sometimes the DC socket does not grip the DC power plug firmly enough to hold it in. Try it again and hold the plug in the socket firmly to see if the fridge will now start. If this corrects the problem you can try expanding the clips on the outside of the Dc power plug a little to get a tighter grip inside the DC power socket. Don't over do it as you may break the plastic.

POWER - PORTABLE FRIDGES THAT START BRIEFLY, THEN STOP - ERROR LIGHT FLASHES ONCE - EXTERNAL BATTERY AND LEAD.

This is almost always a poor quality battery, insufficient battery size, or a poor quality connection between the battery and the fridge. Please review the recommendations under Battery Power in the FAQ section. Please note that the DC current can rise over 5A shortly after the fridge starts, or if the compressor and fan automatically switches in to a higher power cooling mode. If your battery is a bit small, the charge is getting low, your solar panels are not big enough or your DC power cable is not big enough (or any combination of these factors) then this extra current demand may be just enough to kick in the low battery voltage protection even though the battery voltage appears OK.

POWER - FAN STARTS IMMEDIATELY AT FULL POWER - NO COOLING

Return the fridge for repair or warranty service

POWER - FAN RUNS AFTER STARTUP DELAY BUT COMPRESSOR DOES NOT RUN - NO COOLING

Return the fridge for repair or warranty service

POWER - FAN AND COMPRESSOR RUN AFTER STARTUP DELAY - NO COOLING AFTER A REASONABLE TIME

Return the fridge for repair or warranty service