If my electric vehicle breaks down, can it be fixed on the side of the road or does it need to be taken to a garage? – The Irish Times

It depends what went wrong. Generally speaking, with electric cars, any problem requiring roadside assistance will fall into one of three categories: a flat tire, a flat battery, or a major electronic failure.

Overall, electric vehicles have proven to be more reliable than their petrol and diesel rivals, at least when it comes to big-ticket items like engines and batteries. Which?’s research found that electric car owners were having to visit dealers to sort out problems slightly more often than with conventional cars – 31% of electric vehicle owners compared with 29% of diesel car owners – but these problems were mostly related to software, rather than anything that could leave you stranded on the side of the road.

However, there can be big problems, and in that case the short answer is that it is extremely unlikely that your EV will be repairable on the side of the road. These large batteries have a lot of voltage, and current regulations say that they can only be handled by a trained technician, in a controlled environment, wearing the appropriate safety equipment.

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What about towing an electric vehicle?

When it comes to towing, it’s generally recommended to never, ever tow an electric vehicle. Technically, electric vehicles don’t have a neutral gear, and the drive wheels are always connected to the battery, so towing them will overload the car’s regenerative braking system, which can damage the engine and battery.

There are some escape clauses though. If your car is front or rear wheel drive, companies like the AA have special folding tow trailers that lift the drive wheels off the road, allowing you to safely tow your car. However, if your car is four wheel drive and has two electric motors, it shouldn’t be towed at all and will need to be towed away on a flatbed trailer.

There’s also an exception to this rule. Rivian, the US maker of electric SUVs and pickups, includes an emergency towing mode in its cars that not only allows for towing with all four wheels on the road, but cars can also be safely charged while being towed, although Rivian says this is only for emergencies and cars shouldn’t be charged for long periods of time. For now, this is limited help for Irish consumers – Rivian doesn’t sell any cars here yet, although a few have been privately imported – but Rivian and Volkswagen have just signed a €5 billion deal to jointly develop new software for electric cars, so perhaps the emergency towing feature will make its way to VW products in the future.

Can I buy a small battery that I can carry in the boot and plug into my car, which will give me a few extra miles if the battery dies before I can get to a working charger, such as a can of petrol or diesel?

If it’s a flat battery, then there are a few options. Again, roadside assistance services like AA have emergency batteries on board that you can plug into your car and that will provide a small charge, usually enough to get you to your local public charger. Of course, in Irish parlance, this may be of limited help given the sparse nature of the public charging network, but even if it only gets you to a spare charger, at least you won’t be stranded on the side of the road.

Some EVs – notably Hyundais and Kias – now also feature V2L (Vehicle to Load) charging, meaning they can charge another electric device – like your car – from their batteries. This requires a special cable, though, and of course a friend with a suitable EV to help you out.

Can I still open the doors of my electric vehicle if the battery runs out?

In short, yes. This may come as a bit of a surprise, but all electric vehicles actually have two batteries – a large one that powers the electric motors that power forward and reverse, and a smaller 12V battery, very similar to the one used to start the engine in a conventional diesel or petrol vehicle.

This 12-volt battery powers systems like electronic door locks and the like, so yes, you can still open your doors if the main battery goes dead.

Now, that 12-volt battery also needs to be topped up, and most EVs do it the same way conventional cars do, by charging it while you drive. If that, too, runs out of juice, you could have a more serious problem, but all EVs with electronic door openers will also have a physical manual emergency switch. Check your owner’s manual to find out where the mechanical release handles are.

If your 12V battery goes flat, you can ‘jumpstart’ it from another car using a set of jumper cables, just as you would a flat battery in a conventional petrol or diesel car. However, you need to be careful – check the fine print of your vehicle’s warranty, as in some cases, tampering with the car’s electrical system – and jump starting qualifies as such – could potentially invalidate some or all of your warranty.

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Check and see if the car has a comprehensive roadside assistance service and call them to charge the 12V battery as they are recognised experts and if they do it will not affect the warranty. Apart from warranty issues, there is a delicate and important piece of equipment in an electric vehicle called a DC-DC converter which allows the high voltage current to flow from the large battery to the low voltage systems which power things like power windows, seat heaters etc and this current also passes through the 12V battery.

Improperly jump-starting a 12-volt battery can affect or even damage the DC-DC converter, leaving you with a huge repair bill. For the same reason, don’t try to jump-start a petrol or diesel car with a 12-volt battery in an electric vehicle – use a portable battery instead.

What about flat tires?

Flat tires can potentially be fixed on the side of the road. All cars must have at least a tire repair kit, with a can of “fix fluid” that can be injected into the tire to fix small punctures (like when you’ve run over a nail or screw) and an air compressor to re-inflate the tire.

Of course, this is only a temporary solution, and now you need to find a tyre fitter to replace the damaged tyre. Similarly, the AA and mobile tyre fitters could potentially call you on the side of the road to replace the damaged tyre, although with electric vehicles generally moving towards larger 18, 19 and 20-inch wheels, finding a local supplier with the right tyre in stock may be difficult, to say the least.