The power behind the green machine

The Earth 2000 television programmes will feature a team of six pretty tough guys and gals. The kit they will be using to undertake their ecological challenges will be equally tough and very hi-tech.

Helicopters, high speed power boats, mini-submarines and powered paragliders are all part of the Earth 2000 project’s equipment, and indispensable is the small fleet of zebra-striped off-road vehicles.

There was some competition between car manufacturers to be the chosen Earth 2000 vehicle, culminating in Ford coming out on top. The 4×4 Zebras may, at face value, look like conventional off roaders with a jazzy paint job but they are specially built at a cost of £120,000. They are the most technically advanced expedition vehicles in the world.

The vehicles are fully air conditioned with wrap around remote CD player but here conventional extras end. They have a full external protection package including front ball bars and headlight guards, full under-carriage protection guards, baffle guards, side running boards, transmission guards and rear fuel section guards. The specifically engineered roof rack has lockable stowage for diving gear, four 20l jerry cans in shock brackets, extra spare wheel, jack mounts and rear ladder.

Mounted on the roof are four long range Cibie Halogen spot/fog lamps plus rear mounted roof spot lamp for reversing.

The interior is fitted with internal roll cages, Luke 3-point safety harness fitted to specially built Recarro seats plus Pentagon auto tine darkened windows. The vehicles are tracked at all times by 21 orbiting satellites and carry Silva Navigator GPS accurate to within metres. In addition, fitted hand-held units are also fitted with ICOM prototype radio equipment incorporating vehicle to vehicle, ground to air (118-136MHz) ship to shore and surface to sub (156-161MHz), as well as long distance short wave (500kHz-30MHz) transmissions. The radio equipment fitted will transmit from 500kHz to 2GHz on AM, WFM, CW, USB, LSB and NFM. 2GHz transmission is effectively ground to space communication.

The security multi-defence, anti-hijack system innovations feature A200 alarms with Protector smoke defence machine (you break in you get smoked out) plus Sentinal silent alarm paging system and Securfix anti-smash windows all round with high security rear cage for vital equipment.

Further modifications include a snorkel system relocated air filter plus silicon coatings on all electrical equipment for water crossings. All-terrain tyres with two spares are included, along with Airjack Easy Lift system, 2.7/turbo diesel with full tool and spares kit plus a front mounted electronic 5ton Ramsey winch. There will be many occasions when the trucks will be travelling through remote parts of the world, and in which there is no access to mains charging facilities. So they can continue to run all the essential gadgetry, they must rely on solar power to supply the charging current for the battery.

When considering the size of the solar panel needed, it had to be large enough to provide sufficient current to charge the battery over its normal daily cycle period. The Earth 2000 vehicle is equipped with a 12V Sportline battery from CMP. Batteries Standby Division to power the on board computers it is a heavy duty battery with a cyclic service life that is approximately three times higher than its heavy duty equivalent. It has a capacity that is around six times higher than a standard car battery.

The solar panels that will charge the battery are mounted on the roof of the vehicle. In deciding upon the optimum panel configuration, consideration was given to the minimum levels of sunlight that might be encountered. To prevent any possibility of gradual battery deterioration, it is necessary to provide a degree of overcharging, say 10 to 15%, to ensure full charge is restored.

Because there are periods during the year when the level of sunlight is particularly low in certain parts of the world, the battery has to retain its charge for prolonged periods of time. The dryfit Sportline has a very low self-discharge, and will retain 50% of its nominal capacity after six months idle time.

At the heart of the battery charging circuit is the charge controller. It manages and protects the circuit, as well as keeping the team informed on the state of battery charge and discharge. If the battery voltage drops below a critical level, the controller automatically disconnects the load from the battery. This might happen during a period of prolonged cloud, or when the load becomes excessive.

BATTERY MANAGEMENT

An indicator light will indicate low voltage disconnection, and the controller will not re-connect the load until the battery voltage has returned to a suitable level (ie 12.3V). Similarly, there is a built in feature that prevents the battery overcharging: the controller may reduce the current to a trickle charge or turn the charge on and off over a period of time.

A voltage regulator is placed between the solar panel and the battery to maintain a constant voltage to the battery. As well as a miniature circuit breaker to protect the major circuits from short circuits, a blocking diode prevents any reverse flow of current from battery to solar panels during poor lighting conditions. Indicators also show when the charge current is flowing from the array to the battery and when the battery is fully charged or low.

CMP Batteries Standby Division has supplied two Sonnenschein dryfit batteries for each truck – the dryfit Sportline range for the on-board computers and communication equipment, and the dry-fit Start battery (Type DS 80) to get the engine going. This battery is recharged from the vehicle’s alternator.

The dryfit Start battery exhibits good operating characteristics in extreme conditions when compared with conventional ‘wet’ lead acid batteries. It offers better cold start characteristics at -18 deg C, and a longer service life during its cyclic operation. This even applies to vehicles subjected to continuous charging and discharging.

The dryfit Sportline battery provides another significant safety advantage: it can operate at any angle and even under water. This means that the Earth 2000 expedition team can use it to power all of their sophisticated hi-tech equipment, including the bilge pumps of their boats, or to power emergency safety beacons should their vessels become waterlogged.

So when you are enjoying the exploits of the Earth 2000 team this year look out for the batteries and judge their reliability for yourselves.