Updated December 2015

Our solar equipped RVs

The first of our solar equipped RVs was a now rare 1971 VW Kombi Westfalia camper. We modified it during 1994 for across extensive Australia dirt road usage. It was basic, as were most RV solar systems back then. It had an 80 watt Solarex solar panel on a roof-mounted tiltable base and a truly basic solar regulator. The 100 amp hour deep cycle battery was also charged whilst driving (via a voltage sensing relay that protected the starter battery from overly discharging) from the VW’s alternator.

Kombi tilted module

The trustworthy VW Kombi and my wife (Maarit) just off the Strzelecki track – camping overnight. Pic:caravanandmotorhomebooks.com 

The system powered a 40 watt Engel chest fridge. It also powered three 20 watt halogen globes (of which only two were used simultaneously). Whilst solar capacity was less than I advise nowadays – this was done in an era where even 80 watts cost about $750 (at least $1000 in today’s terms). It worked well for us as our travelling was mostly in the northern parts of Australia in times of adequate and reliable sun.

The Kombi proved 100% reliable over some 25,000 km of mostly corrugated dirt tracks (including the Birdsville, Oodnadatta and Strzelecki), but its low slung engine precluded deep water crossings. Primarily because of this, it was sold a few years later – when we purchased an OKA ex-mining truck.

OKA

Our next of our solar equipped RVs was an OKA. This is an Australian designed and built 5.5 tonne 4WD truck intended for fully off-road use. Some 550 or so were built from 1993-2010 or so, but then ceased production. They are now much sought after as they make stunningly reliable go anywhere motor homes. Most sell for well over their original new price even after several hundred thousand kilometres!. Ours was the 14 seater coach-bodied version, and made in 1994. It was purchased after hard nine months on a Singleton coal mine.

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The OKA crossing the Wenlock river on the track up to the tip of Australia’s Cape York – the dome in front of the solar panels is the active antenna for the Westinghouse satellite phone.Pic:caravanandmotorhomebooks.com 

The roof was replaced by a fibreglass pop-top (for which a mould was made). The interior was stripped out and a dinette/double bed plus kitchen and extensive storage was built of aluminium that was then white powder-coated. The entire interior weighed less than 75 kg.

Twin 220 litre water tanks and twin 210 litre fuel tanks were installed, plus a second spare wheel and a firewood rack.

The alternator was replaced by a Bosch 140 amp unit. This charged the 400 amp hour lead acid deep cycle battery bank via an early TWC smart alternator regulator, via an early Redarc voltage sensing relay. Two 100 watt Solarex solar panels were located on the rigid front part of the roof and charged via a Plasmatronic PL20 regulator.

The main loads were a 71 litre eutectic Oz Fridge, plus a huge Westinghouse satellite telephone/fax system. Back then these were the size of a large suitcase and weighed some 15 kg. Its dome antenna can be seen in the photograph.

Lighting was still halogen globes – of which we had 12 (each switchable) of 10 and 20 watts each.

This vehicle was used extensively for driving across Australia (via Alice Springs) from our then home in Broome (see All Solar House)  to the east coast and back. This return trip of some 13,000 km was done 12 times in the OKA and three times with its successor. Some 80% of each return trip was off-road (and usually there and back inside six weeks). 

The Westinghouse satellite fax/telephone proved totally reliable but energy hungry. It was replaced in 2002 when the early hand-held versions became available. This reduced the OKA’s energy draw. That in turn enabled us to reduce (house) battery capacity to a single 120 amp hour sealed lead acid deep cycle unit.

Whilst ideal for its intended purpose – of traversing long distances over rough going – an OKA is too large and unwieldy for everyday use. As we also had a 2005 Nissan 4.2 litre Nissan Patrol, a Suzuki Sierra, and a 2005 4WD dual cab Hilux, we reluctantly sold the OKA to a buyer from QLD (who flew over and drove it home). The third of our solar equipped RVs was one of the then newly introduced Track Trailer 780 kg TVans. It was pulled with ease by the Nissan Patrol.

Nissan Patrol/TVan

For the third of our solar equipped RVs (a 2005 4.2 litre turbo-diesel Nissan Patrol and TVan we decided to go virtually all-solar (i.e. using alternator charging in the Nissan only during long overcast areas when down south). Each vehicle had its own self-contained system.

The Nissan had two by 100 watts Solarex solar panels on bars on the Nissan’s roof. This charged a 110 amp hour Ritar AGM battery (via a Plasmatronic PL 40 regulator). The alternator was not normally used for charging but if needed it was done via a manually switched voltage sensing relay. Its main load was a 60 litre slide-out Engel fridge. It also drove a single outside light that lit up the external slide-out kitchen at night.

Solar TVAN and Nissan Mitchell Falls

Nissan Patrol and TVan set up for the night at Mitchells Falls (in Australia’s far-north Kimberley).  Pic: caravanandmotorhomebooks.com

The Nissan also had the very first production model of the Redarc BMS 1215 Battery Management System on long term (some three years) off-road trial. This was driven from the Nissan’s alternator and (for assured control purposes) drove a dummy resistive load. (It worked superbly over some very rough 75,000 km. It lives today in semi-retirement in our garage charging a battery for outside lighting).

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Plasmatronic PL20 indicates a comforting 12.5 volts on load (in the TVan) Pic: caravanandmotorhomebooks.com

The TVan had a single roof mounted 50 watt Sharp solar module. This charged a 100 amp hour AGM battery via a Plasmatronic PL20. Its load was two by 5 watt interior LEDs, an external 5 watt LED, a water pump, the pump and fan for a Webasto diesel-powered heater, my wife’s laptop computer, Telstra Next G email and (if very cold) a 12 volt electric blanket (for about one hour). Whilst this seems like a heavy load it was typically less than 15 amp hours a day and covered adequately in winter months up north and summer down south. I would have prefered more, but there was no readily available space.

The two systems could be interconnected if needed (but that never once was).

The Nissan/Tvan experience was such that I strongly recommend this dual system approach for solar equipped RVs, particularly for 4WDs towing camper trailers. It does require roof space for the solar panels – but the more one travels, the less one tends to carry – so we had no need to carry anything other than the solar panels on the roof.

Each system worked without any problems over a combined plus 120,000 km of which some 80,000 km was on Australia’s inland corrugated dirt roads – and often in 36-40 degrees C heat.

(Those interested in off-road travel may be interested in the author’s 1959-1960 trans-Africa trip – Last Drive Across Africa).

Full details of every aspect of designing, installing and using solar (plus all about RV electrics) is in my associated books Solar That Really Works! and Caravan & Motorhome Electrics. Both (plus many up-to-date articles on all aspects of RV solar and electrics) are on my associated website: caravanandmotorhomebooks.com.

This successfulsolarbooks.com website is in progress of redesign. All existing articles are being updated and/or rewritten and many more will be added.