There’s no doubt that battery and solar development in the RV arena has advanced rapidly over the last decade or so. AGM, gel cell, lithium, inverters and solar panels are all part of the technical jargon these days. However, although most devices these days can be powered by 12V battery supply, it’s not quite so easily achieved with higher-powered devices because of battery capacity and weight factors.
When Mat Perks from Australian Motorhomes and Caravans (AUSMHC) first contacted me about a new Condor caravan that AUSMHC was working on, the Land Bruiser Hybrid, I initially thought it was a caravan/camper trailer combination because that’s the jargon the camper trailer industry uses. But it turned out to be something a little different and, in my opinion since it involves high-capacity lithium LiFePO4 batteries, technically interesting.
THE DOWN LOW ON THE VAN
The van AUSMHC used for this project was a Condor Land Bruiser. The caravan is designed for offroad use and has an external length of 6.4m (21ft) and an ATM of 3700kg, which with a tare of 3040kg, gives a payload of 660kg. Just a tow vehicle note here, although I was using a Chevrolet Silverado, something like a Toyota LandCruiser can still be used, but the maximum tow rating of 3500kg reduces the payload to 460kg.
POWER TO THE PEOPLE
Undoubtedly the most interesting feature of this van is the electrical setup. Electrical systems in caravans have evolved over the last few years into a dual voltage arrangement — 240V mains power is for items like the three-way fridge, microwave oven, air-conditioner, water heater and mains battery charger, while 12V is for lighting, compressor fridges, water pump, TV and radio. In recent years, 12V power use has certainly increased with a rise in the number of AGM/gel cell batteries fitted, and in more recent times lithium LiFePO4 batteries have become more common. In tandem with that, many an RV roof is now plated with solar panels, which allows self-sufficiency away from mains power.
Although lithium battery capacity has increased recently, it requires a considerable amount of battery capacity to run something like an air-conditioner. The team at AUSMHC decided to do something about that, hence the Land Bruiser hybrid.
At the heart of the electrical system are two discrete battery systems. The first is a conventional 12V DC setup, with two 100Ah AGM batteries and a BMPRO Battery Plus 35PM battery management system. It supplies all the conventional 12V loads and the charging cycle operates as normal.
The second system is set up quite differently and most of the work was done by the AUSMHC team. Manufactured by Dyness, there are three 50Ah 48V DC lithium battery modules. They are connected to a Victron 3000VA inverter/charger which not only charges the batteries but supplies devices like the induction cooktop, convection microwave oven, air-conditioner and under-floor heating — the latter is certainly something a little new here. There are two 90W electrical heaters installed, one in the bathroom and one under the floor area at the foot of the bed, which are powered directly from the 48V batteries.
Although the two battery systems are separate, each with its own mains charger, they are able to be commonly charged by the 1050W solar panels mounted on the roof or from an optional portable generator.
All of the above is controlled and monitored by a Simarine touch panel which, in addition to the batteries, chargers and solar panels, also monitors items like the water tank levels, gas cylinder levels via a sensor, temperatures and even air pressure.
In addition to that, something like an iPad or tablet can be used via the van’s inbuilt wi-fi for much the same purpose. To say the least, it’s very sophisticated and a tech geek’s delight whilst still being simple to use.
Remote support for the 48V system including the solar and inverter is possible via the Caravans wi-fi/4G connection, meaning AUSMHC can remotely troubleshoot any issues wherever the caravan is located, provided it’s within Telstra’s coverage area.
The Land Bruiser is built in a somewhat familiar fashion. It has a hot dipped galvanized box section chassis with 150mm rails and drawbar. Both the galvanised sheet protected water tanks are fitted forward of the wheels but there’s no grey water tank. The van rides on Control Rider TS independent suspension fitted with coil springs and two shock absorbers per wheel. A Cruisemaster DO45 hitch is fitted to the pointy end. There are two battery boxes fitted to the offside rail forward of the wheels, but they are empty as the batteries are fitted inside the van. Brush bars are fitted back and front on both sides.
A Meranti timber frame gives the caravan body strength, and it is supplemented in the roof by an aluminium H frame for the air-conditioner. Smooth sided Alucobond is used for the cladding, as well as the ubiquitous black alloy checkerplate. It’s all fully insulated.
In addition to the usual essentials on the drawbar, there are two gas cylinders and an alloy checkerplate storage bin, designed to take items like a generator and a Weber BBQ on slide-outs. In addition to a spacious front tunnel storage, there is also small bin on the rear nearside.
The Land Bruiser has a forward door entry with an island bed up front, nearside dinette, offside kitchen and a full width rear bathroom. Black and white is the colour scheme of choice, black being for the cabinetry and upholstery and white for everything else!
Measuring 1.88m x 1.52m (6ft 2in x 5ft), the island bed has large windows, 12V Sirocco fans and mirror door wardrobes on both sides. There are pillow cubbies on both sides also, which, in addition to a handy bit of bedside storage, also offer wireless phone chargers. Given the adjacent entry door, the bedside walk around space is quite good.
NEW STYLE COOKING
What grabs the attention in the kitchen bench, apart from the generous number of drawers, is the lack of the usual gas ring cooktop. There’s the usual stainless steel sink and drainer which sits alongside a Safiery double induction cooktop — sitting almost flush with the benchtop, it fits in very neatly. There’s no oven fitted but underneath the cooktop is a Sharp convection microwave oven.
In keeping with the all-electric theme, the Dometic fridge is a 190L 12V compressor model.
The two-person club lounge style dinette looks slightly disproportional but that's mostly because of what’s under the seats — batteries, with 48V to the left and 12V to the right. This means overheard lockers offer the only storage in the dinette area, but it also means all the battery weight is directly over the axles.
A little surprisingly, the TV isn’t in its usual location at the end of the kitchen overhead lockers by the bed. Instead it’s flat mounted on the bathroom wall. From here its fairly easily seen from the bed but less so from the dinette with only one person having a decent viewing position.
Across the rear, the bathroom has a slightly different layout. It’s deeper so even though the shower cubicle is fitted in the rear offside corner, there' still room in front of it for the Thetford cassette toilet. Filling the nearside rear corner is an L-shaped vanity cabinet complete with pedestal wash basin, illuminated wall mirrors and a top-loading Sphere washing machine.
And there’s enough space for a linen cupboard with drawers below in the remaining corner. There's towel rails and fan hatches, plus a hair dryer as well.
THE BOTTOM LINE
It’s a very bold step by AUSMHC to undertake a project like this and the innovative use of 48V DC batteries is an interesting step to the future. I suspect some customers may still want a gas hob and oven, however with this setup, no gas appliances removes the need for gas ventilation and thus eliminating dust ingress. It’s an interesting demonstration of how induction cooking can still be done, and the air-conditioner used without being hooked up to mains power. Although this is a fairly conventional caravan in build and layout, the electrics have taken the power side of things to a new level.
WHY VOLTAGE MATTERS
For those who might be wondering why there are two different battery voltage systems, here’s a brief explanation. Electrical power (P) is a product of voltage (V) and current (I) — note that the symbol for electrical current is I not C as you might expect.
The formula is quite simple for direct current (DC) as supplied by a battery, that is P = V x I. So, for the same power output if the voltage is multiplied by four then the current is reduced by the same amount. That’s important when considering cable sizing because the size of the copper wiring conductor is related to the amount of current it can carry. The smaller the diameter of the conductor, the less current it can carry, and voltage drop issues become more problematic. In short, in order to avoid having to install large diameter copper cables for high power devices, it’s a good design approach to increase the voltage instead.
As an example of this, anyone who has done RV travel in the USA will know just how large the power cords and related fittings for connecting up an RV. Domestic voltage in the USA is 110V AC, compared to 230V AC in Australia, so the US fittings for 30A and 50A are to our eyes an amazing size.
WEIGHTS AND MEASURES
Body length 6.4m (21ft)
Overall length 9.06m (29ft 9in)
Width 2.4m (7ft 10in)
Height 2.95m (9ft 8in)
Ball weight 300kg
Cladding Alucobond walls, one-piece fibreglass roof
Chassis 150mm hot dipped galavanised with 2in raiser
Suspension Control Rider, independent suspension with coil springs and shock absorbers
Coupling Cruisemaster DO45
Brakes AL-KO 12in electric
Wheels 16in alloy
Water 2 x 95L
Battery bank 1: 3 x 50Ah 48V Safiery lithium (2400AH DC in total)
Battery bank 2: 2 x 100Ah 12V AGM
Air-conditioner Truma Aventa roof
Gas 2 x 9kg
Sway control No
Cooking 2 hob Safiery induction
Fridge Dometic RPD190 12V compressor
Bathroom Thetford cassette toilet & separate shower cubicle
Hot water Swift 28L gas/electric
PRICE AS SHOWN
$129,990 (NSW, drive away)
Australian Motorhomes & Caravan
31 Pacific Highway
Bennetts Green, NSW 2290
P: (02) 4948 0433