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Three years after the presentation of the E-Home Coco e-caravan, the Allgäu-based caravaning manufacturer Dethleffs has taken on the challenge of crossing the Alps almost 400 kilometers in length with a purely electrically powered combination without intermediate charging.
In a joint development project, the Caravanning-Manufacturer Dethleffs, in cooperation with the technology group ZF Friedrichshafen, completed an Alpine crossing from Isny in the Allgäu to Riva on Lake Garda with a purely electrically powered caravan combination without reloading. Behind an Audi e-tron as a towing vehicle, the E-Home Coco was the first caravan with a driven axle to be used.
Not so easy
As early as 2018, Dethleffs presented the prototype of an E-Coco caravan with its own electric drive at the Düsseldorf Caravan Salon, back then still on the hook of a BMW i3. And to show that the system is working, you should cross the Alps as soon as possible without recharging. The technical implementation turned out to be much more complex than expected, because the first draft of packing the caravan full of batteries that acted as a range extender for the towing vehicle on the way was quickly discarded. There was no interface between the car and the caravan, and no Moover function (remote control for maneuvering the trailer) could be integrated.
So three years passed before the Audi e-tron packed full of measuring devices with the E-Home Coco, which had been registered for individual approval, was sent on its journey in Isny. On board a completely new system with two 40 kWh batteries in the front and rear of the caravan, two separate wheel motors on the driven axle, a control unit and a number of other technical components. The batteries alone weigh 600 kilograms more.
Caravan has to support car
The large Audi SUV with the more powerful 95 kWh battery is specified with a standard range of around 400 kilometers. However, the weight of a caravan and the increased air resistance reduce the range of the towing vehicle by up to 50 percent, and even more under unfavorable circumstances. In order to cover the 386 kilometers over the Fernpass and the Brenner Pass, the E-Coco had to provide so much support that the electric drive of the trailer can compensate for the higher energy consumption due to the trailer operation and the E-Audi also has the usual range with a caravan in the car Reached tow.
The fully electric combination drives south at 80 to 84 km / h on the motorway and a total average of 62,3 km / h. 4.870 meters in altitude challenge the batteries, while on 5.480 meters downhill, eleven (Audi e-tron) and six percent (E-Coco) of the battery charge are recovered via recuperation. However, strong headwinds on the descent from the Brenner not only slows down the electric team, but also initially the optimism of the Dethleffs team. Wrong, as it turns out. With a remaining battery capacity of 13 (Audi) and 6,5 percent (Coco), Riva is reached on the northern shore of Lake Garda.
Positive influence on the ride
The electric team needed six hours and twelve minutes for the 386 demanding kilometers and made the development engineers from Dethleffs, ZF and the Erwin-Hymer Group cheer. The overall balance: 82 kWh of energy consumed by the towing vehicle and 74 kWh by the E-Home Caravan. But the electrically powered Coco influences the journey not only in terms of range, but also through a new driving experience and increased driving safety. The impressions: Acceleration like a solo vehicle, significantly improved directional stability in bends thanks to the low center of gravity and safe straight-line stability because the combination remains straight even when driving downhill. And that's not just a feeling, it's actually measurable.
Dr. In any case, Rüdiger Freimann from the Erwin-Hymer Group's development team and his ZF colleague Udo Gillich agree that caravan trips with purely electric trailers will not only be possible in the future, “they will also become unrestricted driving pleasure maximum security ". However, it will have to wait at least three more years before it is ready for series production.
“We certainly don't need such a large battery in a series caravan,” explains Freimann. A capacity of 20 kWh could be enough. For weight reasons and because the battery is the most expensive component of the system. And whether the fast charging option up to 50 kW, as in the prototype, is sufficient or should be increased is still open. The integration into the home network, keyword smart home, could also take place in both directions. The e-caravan could be charged via its own solar system, but on the other hand stored electricity could be returned to the household. The Moover integration is already working today.
Own drive axle for caravans?
Another high hurdle has to be overcome at the legal level. According to EU law, powered caravans are not permitted at all. At most by way of individual acceptance or for small series up to 1.500 copies. However, Dethleffs boss Alexander Leopold considers it realistic that this could change in the next three years: "Because it fits in with the times and is simply necessary for an electromobile future."
Corresponding legal regulations already exist in the USA, which is why the cult Airstream caravan will be presented with a self-propelled axle at the end of September. Airstream is also a brand of Thor Industries, the world's largest manufacturer of leisure vehicles, which also includes the Erwin-Hymer Group.
