ZF electric trailer axle

We might have known that transmission specialist ZF wouldn’t leave the electric axle market to other European manufacturers. Its eTrailer system has been tested during 2021 and is now being implemented by RV maker, Thor Industries.

We’ve reported on the Huber/AL-KO joint project into auxiliary electric propulsion for motorhomes and caravans, and ZF has entered the field.

Leading US-market RV manufacturer Thor Industries announced in late January 2022 that it had signed a binding memorandum of understanding with German auto supplier ZF.

The deal gave Thor companies exclusive rights to ZF’s eTrailer System in US-market travel-trailer RVs. 

An eTrailer van was fitted with a lithium battery pack between the chassis rails and one or two eTrailer axles were powered by that battery.

The powered van was thus able to assist performance of the towing vehicle and, when required, contribute a braking effect as it recharged its battery on downhill grades.

That assistance was designed to maintain or possibly extend the nominal range of any towing vehicle. Adding a high-capacity battery and a compact drive system to a trailer eliminates one of the main obstacles to electric vehicles operating as towing vehicles: greatly reduced range. 

Other plusses are much more battery capacity to power the van when camped and self-driving capability, allowing easier parking and coupling.

The eTrailer communicates with the towing vehicle via a simple connector and, when separated, can be driven and steered independently in any direction, via a hand-held remote control.

In July 2021, a test demonstrated the eTrailer system’s potential when an eTrailer-equipped lightweight camper was towed by an Audi e-tron Sportback from Germany to Italy – over the Alps. 

The Audi towed the eTrailer RV the full distance of 386km on a single charge and arrived at its destination with power still remaining in both the eTrailer battery and the e-tron battery. 

Incidentally, Audi’s stated range for the e-tron, without a trailer in tow and certainly not handling Alpine road gradients, is 393km. 

“Thor is thrilled to enter into this partnership with ZF, a global technology company enabling next generation mobility,” said Bob Martin, Thor president and chief executive officer. 

“The eTrailer system, which Thor, Erwin Hymer Group (EHG) and ZF have jointly developed over the last several years, is the only high-voltage solution available in the RV space.” 

Thor owns several US-market RV brands, including Keystone, Dutchmen and Jayco (USA), but the crown jewel in its brand portfolio is Airstream, for which Jayco Australia is a distributor. 

The aircraft-inspired, aluminium-skinned, ‘retro’ Airstream is the top-shelf model and the logical recipient of the initial eTrailer componentry.

If that proves to be true, we could see Jayco-imported Airstream eTrailer units Down Under.

However, the testing phase showed up several issues around the possible situation where a ‘rogue’ trailer axle could push the tow vehicle into trouble. We asked Thor and Jayco for input in late-2024.