We compare the 40L Engel, National Luna and Weaco. (2007) with video.
The Campmaster 45L is a later addition and is not included in the video, but is included in the written report below and the Kellerman 60L is mentioned.
Reflecting back to 1982 when I bought my first 4×4, the first items I wanted to add to my vehicle were a nice sound system, somewhere to fasten a Jerry-can and a high-capacity alternator. A winch, roof-rack and a bigger fuel tank were on the list, but the installation of a fridge was a luxury I didn’t dare think about. They were expensive, unreliable and inefficient. A cool-box would have to do. Today, as I consider buying myself one of these new Land Cruiser Wagons, fitting the freezer is among the first things I contemplate.
Fridges and freezers have become so much of our daily outdoor lives. My first fridge, bought in 1991, was an Edessa heat exchange fridge. It was a complete failure. For years I struggled to get it to work properly and after about three year of frustration, took it back to the manufacturers only to be told that the wrong gas jet had been installed during manufacture. And they insisted that I pay for the repair! No wonder they went out of business. Even then, it didn’t work very well.
In 1991 Gwynn and I spent the year running Delta Camp in the Okavango, where I was introduced to three more gas-fired heat exchange fridges. One performed so badly that it was nicknamed, ‘The Cupboard’. But the other two, after tinkering and using the knowledge gained with my Edessa, were soon performing brilliantly.
My first descent vehicle freezer was a 40-litre Engel. It was a revelation: It actually not only kept things cold, it could freeze! This would have been around 1997. Since them I have owned three makes: Engel, National Luna and Weaco. None of these fridges have ever let me down, that are all excellent, but each excels in their own way. What follows is what I have learnt about vehicle fridge/freezers. I hope it helps you to get the most from these products are assists you in selecting the right one for your needs.
THREE TYPES OF FRIDGE/FREEZERS
The three main types are Compressor, heat-exchange and thermo-electric cooler. All have advantages and disadvantages.
Compressor fridges
The best compressor freezers run on both 12-volt and 220-volt without an additional power supply. Because they are controlled by an adjustable thermostat, current draw is more efficient maintaining the fridge and its contents at a temperature controlled by a knob. Some designs have a thermometer. The colder the setting, the higher the current consumption both in attaining the desired temperature and maintaining it. Space utilization varies from efficient to down right bulky.
Thermo-electric coolers
Thermo-electric coolers run on the Peltier principle that if a current is passed through a special metal element it becomes cold and if the current direction is reversed the element gets hot. So thermo-electric can also be used to warm up food. Apart from a small fan, thermo-electric fridges are solid state and very quiet but will not freeze and are slow to cool when compared to compressor fridges.
They run off 12-volts and are not thermostat-controlled, meaning that they are inefficient in terms of current consumption. Get one if you will be satisfied with only running it when the engine is running, drinks that are cool and not cold and no chance of freezing anything.
Heat Exchange Freezers
Powered by LP gas and by 12-volts and 220-volts, heat-exchange fridges are inefficient when run off 12-volts, fairly efficient off 220-volts and highly efficient running on gas or paraffin.
The versatility of power source means that in situations where they remain in one location for a long period when battery charging is not possible or practical, they keep working. In a vehicle they must, for safety reasons, work off 12-volts. However, when in a moving vehicle or trailer under electric power they do lose efficiency and depending on outside influences, may not freeze. When set up in a fixed location they must be levelled, the flame centred, the regulator set and a yearly cleaning. They have no thermostat so when working off 12-volts the current draw, which averages 7-8 amps is not controlled. I.e. it runs 24-hours a day. This makes them hugely inefficient on 12-volts.
SELECTING A COMPRESSOR FRIDGE/FREEZER
Engel, Weaco and National Luna currently make the best portable fridge/freezers anywhere. Minus-40 also make a good product but they are all so unnecessarily large they are for the most part impractical for use inside a vehicle. Some other makes are appallingly inefficient and don’t perform even to their own specifications under real hot, humid conditions inside a vehicle.
My advice is dismiss them and look for solid word-of-mouth recommendations. Secondly, I believe that it’s as much about how the current is put back into the battery than how much is taken out.
Because 12-volt compressor freezers are by far the favourite for the 4×4 operator, I will confine my detailed discussions to this type.
Beware of false current draw claims
It is so easy for freezer manufacturers to claim exceptionally low current consumption for their products and tout theirs as better than the competitor’s. This is how it is done, without lying: Make a statement like: Current draw 2,5 amps @ 12 – 24 volts. Such a freezer is likely to draw 3.5 amps @ 12 volts, 2.5 amps @ 18 volts and 2 amps @ 24 volts. Because a healthy, charged battery will operate between 12,5 and 13,8 volts, in this way the figures published look better than they really are when the freezer is used out in the field, in a stationary vehicle, when a healthy battery will delivery 12,8 volts and not much more.
On a recent shoot for my second TV series to be broadcast later this year, I tested these three fridge/freezers and compared them in all the ways I know how, running off the same power source and here are my findings.
These tests were done in the field, without much scientific data, no professors looking on and nobody to ‘adjust’ the findings. I prefer to use practical, in-the-field testing: It was a humid day, outside temperature in the high twenties, a little wind and lots of birds singing in the trees. That day I saw my first Trumpeter Hornbill.
ENGEL 40L fridge/freezer:
• Best current draw was 2,5 amps @ 12.8 volts.
• Insulation thickness middle of the three.
• Lowest recorded temperature: -14,4°C (Measured by external meter)
• Easy to operate single knob for adjustment. Can be knocked, i.e. adjusted ‘accidentally’.
• Time to freeze from turn-on: I would say extremely fast.
• Removable lid.
• One large basket with no dividers. (The least practical of the three)
• No internal light.
• Thermometer included. Inaccurate; should be used as a guide only.
• Compact and good space utilization. Not as heavy as the Nat Luna.
• 12 volt and 220 volt. No external power supply.
• Removable power cable supplied.
• Excellent record of reliability, spare parts supply and service backup.
• Priced in the middle of the three. Excellent quality.
NATIONAL LUNA 40L fridge/freezer:
• Best current draw was 3,4 amps @ 12.8 volts. (Higher than claimed by makers)
• Thickest and therefore probably the best insulation of the three.
• Lowest recorded temperature: -15,6°C (Measured by external meter)
• A little awkward to adjust settings (Needed to consult book to remind me how to do it) Cannot be readjusted ‘accidentally’.
• Time to freeze from turn-on: I would say maybe the fastest of the three.
• No removable lid. (Significant drawback in a vehicle)
• Two baskets. Practical size and shape. (Best of the three)
• Internal light which did not work properly because of poorly designed plug fitting.
• Thermometer included. Inaccurate; should be used as a guide only.
• Less compact, the largest and heaviest of the three.
• 12 volt and 220 volt. Hella-plug external power supply. (Nice)
• Power cable cannot be removed. (Annoying)
• Excellent record of reliability, spare parts supply and service backup.
• The most expensive of the three. A very well-made product but I don’t see the value in the additional price.
WEACO 40L fridge/freezer:
• Best current draw was 4.0 amps @ 12.8 volts.
• Thinnest and therefore probably the poorest insulation of the three.
• Lowest recorded temperature: -15,1°C (Measured by external meter)
• Very easy to adjust settings. Unlikely to be readjusted ‘accidentally’.
• Time to freeze from turn-on: I would say fast, but not as fast as the others.
• Not only a removable lid, it can be reversed. (The best of the three)
• One basket with divider. Practical size and shape.
• Internal light, cleverly designed and practical. (The best of the three)
• No thermometer included but I understand new version has one.
• Most compact; the smallest and by far the lightest of the three.
• 12 volt and 220 volt. No external power supply needed.
• Removable power cable supplied.
• Imported by Outdoor Warehouse. Weaco has been on the market for an insufficient period to record dependable reliability statistics, but so far looks good.
• The least expensive of the three, good value, and made chiefly of plastic so does not feel as well made as the others.
Camp Master 45L 12/220V
NB: I do not think this is a 45L fridge – I don’t think it is much above 40L. I believe the claim that it is 45L is incorrect, mis-measured or deliberately mis-advertised.
• Best current draw was 2.8 amps @ 12.8 volts. Excellent. The econ setting at which this current draw was measures must not be used as a start-up but only once the freezer has attained its selected temperature. Boost setting draw is ±4,5 amps @ 12.8 volts.
• Thick insulation, similar to National Luna.
• Poorest build quality of them all..
• Lowest recorded temperature: -19,1°C (Measured by external meter) The lowest of the four.
• Very easy to adjust settings. Unlikely to be readjusted ‘accidentally’. Econo switch vulnerable and could be switched or even damaged in the beck of a vehicle.
• Time to freeze from turn-on: I would say the fastest of them all
• No removable lid but I understand newer versions will have one
• Two baskets – very practical – and an extra 0.5L capacity over the rest.
• No internal light.
• Thermometer included that was the most accurate on test.
• Compact; – an extra 0.5L capacity for similar volume as Nat Luna.
• 12 volt and 220 volt. No external power supply needed.
• Fixed 12V cable cannot be removed.. Hell-plug also supplied.
• Sold by Masmart, available at Makro. Good service record backed by the makers and Danfoss Compressors.
SUMMARY
My current fridge/freezer of choice is a 60-litre Kellerman, half fridge, half freezer. It is still under review so is not in this comparison, it being done in 2008, but it could turn out to be the best value for money fridge freezer on the market today. Engel and ARB are good products no doubt, but are too expensive because excellent South African-made products are now available. And as for National Luna, why the price? I cannot see it and it and it’s made here!
MORE ON VEHICLE FREEZERS:
Additional ideas when selecting a compressor fridge/freezer:
• Compact and efficient space utilization because space in a vehicle is always at a premium.
• Stainless steel looks better in the shop but deteriorates rapidly and before long looks shabby in the vehicle. Stainless steel is a particularly poor insulator so a stainless fridge will be less efficient. Definitely not worth the extra cash, in fact, they should be cheaper.
• Buy new. Old designs are far less efficient as new technologies have improved designs significantly over the past five years.
• In the confines of a vehicle, a removable lid is a real bonus.
• Internal lighting is nice but not essential.
• Low-voltage cut-out is essential and prevents a battery voltage from dropping to a level which could cause damage. Even a deep-cycle battery can be damaged in this way.
• Tie-down handles ensure that the unit can be well secured which is essential for travel in rough country. To prevent damage to the fridge, it must be secured.
• A slide-out tray, on which to bolt the freezer, is really worthwhile.
Setting up
Vehicle equipment centres tell me that in 99% of cases when a freezer has been returned as faultly, it is the home-style fitting done my the owner that is to blame. Poor current flow caused by a combination of cheap connectors and thin cabling is the most common cause of problems. When the compressor starts up, the current draw, albeit only for a second or two, can soar to 15 amps. Use the best quality connectors you can find.
When calculating the cable core thickness required, divide the length by 1000. E.g., if the cable length is 3 metres (3000mm) then the minimum cable core thickness is 3mm and if the length is 4 metres then 4mm cable is required, and so on. This will ensure adequate current flow along the length of cable, no matter how long it is.
Crimping is far better than soldering. Soldering is far better than twisting two wires together and then binding with insulation tape. The sad thing is, some 4×4 fitment centres do this! Not many use proper, high-quality, heavy duty crimps. I see this as a shortcoming throughout the 4×4 equipment industry.
CALCULATING CURRENT CONSUMPTION
Calculating the consumption of a compressor freezer is difficult in that although current draw with many modern freezers varies between 2,5 and 4 amps, it is switched on and off by a thermostat. So, current draw reduces significantly after the operating temperature is reached. Current draw is now dependent on thermostat setting, quality of insulation, outside temperature and how frequently the fridge is opened.
Preparation: (particularly important for heat-exchange types)
• Cool down everything in your household fridge before packing the vehicle freezer.
• Remove the plastic cling wrap around canned beverages, otherwise the plastic will inhibit air flow and reduce cooling efficiency.
• Liquid is better stored in metal containers as plastic does not conduct heat well.
• Over-filling the freezer will have a detrimental effect on the cooling efficiency.
• Have a clasp to keep the lid tightly closed to prevent it bouncing open.
• By keeping the amount of time the freezer is opened limited, the freezer will consume less current and the contents have a better chance of remaining frozen.
I do not advise fitting freezers or batteries in a trailer because:
• Current loss occurs along the long cable and plug.
• Do not have a battery in the trailer and expect the charge current to pass from the vehicle through the tow hitch electrical socket. A separate socket with a minimum of 6mm core cable is needed or the battery will never receive a proper charge.
• When you go on a game drive the battery will not be recharged, wasting valuable engine charging time.
• The contents of a trailer are shaken about far more than those in a vehicle. Freezers that ride in trailers over long periods can suffer ruptured piping due to vibration.
• Heat exchange freezers can be fitted in a trailer and in some respects is an advantage. They can be leveled and remain unmoved during an extended stay, running from gas bottles in the trailer.
