Breaking down in an EV: flat battery, towing, moving on

An electric car does not stop dead when the display reaches zero. The battery management holds back a reserve below the displayed zero to protect the cells from deep discharge. It is not meant as a driving reserve, but it makes the car wind down in stages rather than abruptly: usually available power drops first, then top speed, and finally the drive shuts off.

How many kilometres lie between the first warning and standstill varies from model to model and cannot be predicted reliably. The display calculates from the consumption of the last few kilometres; a climb, a headwind or cold can shift the sum quickly at the end. Driving into it on purpose means gambling with a reserve whose size you do not know.

When the car stops, steering, brakes, lights and hazard lights generally keep working for a while, because the on-board electrics run from the 12-volt battery, not from the drive. So as soon as power fades, pull over somewhere safe, switch on the hazards and secure the scene as for any breakdown. After that there are three options: some breakdown services carry mobile chargers that add enough for the next charger, though not every service has them everywhere. The breakdown service can take the car to the nearest charging station. Or, if a socket is within reach, the emergency charging cable helps, slowly but effectively.

Most cars warn in several stages: first a notice at low charge, then a clearer message, on some with a suggestion to head for a charger, and finally a symbol for reduced power, often shown as a tortoise. What each symbol means is in the owner's manual, and it is worth knowing before you need it.

From the first warning on, energy matters more than time. Slowing down cuts consumption on the motorway considerably, because aerodynamic drag grows with the square of speed. Turning down the air conditioning or heating helps too, especially at low speed. And set the navigation to the nearest reachable charger, not the one you had planned, ideally checking in the app that it is working.

A message about the high-voltage system or battery temperature is something other than low charge. It can appear with a full battery and, depending on colour and symbol, requires you to stop immediately. The distinction between warnings that demand action now and those that need a workshop soon applies to electric cars just as it does to combustion cars.

On most electric cars the motor and wheels are linked by a fixed reduction gear with no clutch in between. If the wheels turn, the motor turns. A permanent-magnet motor then generates voltage even when the car is switched off. Towed over longer distances, that voltage can damage the power electronics, and motor and gearbox heat up without the cooling running as it does when driving.

Most manufacturers therefore require an electric car to be carried on a flatbed or at least to have the driven wheels lifted; with all-wheel drive, that leaves only the flatbed. Towing with a rope or bar on all four wheels is not allowed at all on many models, or only for a short distance at low speed, for instance to pull the car out of a danger zone. The limits are in the owner's manual. The manual applies, not the habits of whoever comes to collect the car.

That matters when you call: a breakdown service that turns up with a tow truck meant for combustion cars may not be able to take the car. So say on the phone that it is an electric car, which wheels are driven and that a flatbed is needed.

Loading has rules too. The towing eye screws into a thread in the bumper; it is usually kept with the tool kit, and the cover over the thread is not always easy to find. Pull only on that eye, never on suspension parts, and nobody should put anything against the battery housing under the car. Jacks and lifts go at the marked points.

An electric car that has stopped is usually in P, and the parking lock holds it in place. To winch it onto a flatbed or push it a few metres, the lock has to be released, and for that the car needs power, usually from the 12-volt battery. If that battery is flat, the lock stays engaged.

Many models have a dedicated mode for this, called transport, tow or towing mode depending on the maker. It holds neutral, releases the electric parking brake and stops the car from shifting back into P on its own after a short while. How to activate it is in the owner's manual. Read that section once when you take over the car; at the roadside in the rain is the wrong moment.

If the 12-volt battery is flat, many models can be woken with a jump start at the designated connection points. After that the car can be put into transport mode or, if the traction battery still has charge, even driven again. Some manufacturers also provide a mechanical emergency release for the parking lock. Whether your electric car may itself jump-start other cars is a separate question; many manufacturers advise against it.

Electric cars are built so that in a crash that deploys the airbags the high-voltage system is normally shut off automatically: contactors disconnect the battery from the rest of the system. The battery itself stays charged, though. After a crash, nobody without training touches orange cables or components, not even to check something.

The more serious danger sometimes comes later. If the battery housing is damaged, individual cells can short internally and heat up, which can lead to a fire hours or days after the crash. Warning signs are smoke or vapour from under the car, hissing, popping or a sharp chemical smell. Then keep your distance and call the fire service; nobody puts out a battery fire with a hand-held extinguisher.

Tell the emergency services on the phone and at the scene that it is an electric car. For every model there is a manufacturer's rescue sheet showing where battery, cables and disconnect points are. Many motoring clubs recommend carrying it printed behind the driver's sun visor. Rescue services increasingly have this information digitally, but a sheet in the car never hurts.

Afterwards the car belongs outdoors, away from buildings and other vehicles, until a specialist has assessed the battery. Recovery services that handle electric cars regularly know the procedure. The same applies after grounding the car without any airbag deployment, say on a kerb or a rock on a farm track: a dent in the battery housing is a reason to have the car checked before you drive on or park it in an underground garage.

The more precise your details on the phone, the likelier the right vehicle turns up, and the sooner the workshop knows afterwards what it is dealing with. Some of it can only be read while the on-board electrics still work, so note it down before you call. Have ready:

Find out in good time who pays for the help. Many manufacturers provide a mobility guarantee or roadside assistance with newer cars, and whether a flat battery is covered varies: some treat it like a fault, others like an empty tank. The same goes for motoring clubs and insurance policies with breakdown cover. The terms are best read before you need them.

After the tow, where the car goes matters. If the cause was only the charge level, a charging station is enough. If it was the 12-volt battery, almost any workshop can help. If anything points to the high-voltage system, the car belongs at a workshop trained for it that can diagnose your model, and that is not always the nearest one.