How can I store a hybrid car for a long period?

The coronavirus pandemic means a lot of people could be storing their cars for several months. While most modern cars can be left for long periods without any detrimental effects, what does it mean for complicated hybrid vehicles?

First of all, the key message from car manufacturers is you shouldn’t be concerned about the hybrid (traction) battery. This is the big battery which works with the petrol engine to provide power.

In ordinary circumstances, the hybrid system will make sure this battery will never go entirely flat. In Honda hybrids, for example, the system will always retain between 20 and 80 per cent charge. Even if you leave it for a long period, it’ll retain some charge - and the next time you drive it, the petrol engine will recharge the battery.

That leaves the smaller 12v battery. This is the battery you’ll find in any car, which is used primarily to start the car. When the car’s being driven, it charges up the 12v battery, leaving it with enough electricity to start the car next time you use it.

The issue comes when the car isn’t used for a long period of time - when you’re on holiday, for example, or staying at home during a global pandemic. It’s normal for the 12v battery to lose charge over time.

If the battery’s in good health, this should be able to last several months without depleting too much charge to start the car. As batteries get older, they’ll lose charge quicker, and could leave you stranded - so it’s worth replacing your car battery every two or three years.

There are a number of ways you can maintain the 12v battery in your hybrid car so that it’s not completely flat when you need it. Ordinarily, we’d recommend taking the car for a good half an hour drive every week to keep the battery topped up, but that’s not advised in the ongoing COVID-19 situation.

If possible, we’d suggest using a trickle charger such as this CTEK device. This’ll provide your battery with a steady stream of electricity, keeping it charged up and in good health. They’re quite clever in that they can measure how much charge is required, preventing it from overcharging. The downside is that you’ll need electricity to plug the charger into - great if you’ve got a garage with electricity; not so great if you park on the street.

Trickle chargers will work with most hybrid cars that have a separate 12v battery under the bonnet. Before you invest in one, consult your car’s manual to find out if it recommends the use of a trickle charger.

If you haven't used a trickle charger and your 12v battery is flat, most hybrids can be jump-started. Again, it’s important to check your owner’s manual before you do this, and follow important safety precautions to prevent injuring yourself. This video should help.

On recent Hyundai and Kia hybrid models, the 12v battery is tucked away inside the car’s lithium ion hybrid battery pack. That might seem unhelpful if you’re looking to trickle charge or jump start your car - but there is a plus side. They have a clever ‘battery reset’ button on the dash. Press this, and it’ll use the hybrid battery to charge the 12v battery. This means you can effectively jump start your own car from the comfort of the driver’s seat.

Battery concerns aside, there’s not much you need to do when storing your hybrid car. You could consider pumping some extra air into the tyres to prevent flat spots, but this isn’t really necessary with modern tyres.

The important thing is to ensure all doors are fully closed and the car’s locked. This helps security but also minimises drain on the battery.

If your car has a manual handbrake, we’d recommend leaving this off to prevent it sticking - but make sure you leave your car with the automatic transmission in 'park' to prevent it rolling away. Consider placing a brick behind one of the tyres, too.

When you drive the car for the first time in a prolonged period, it’s normal for some surface corrosion of the brake discs to have occurred. This might sound and feel strange the first few times you use the brakes, but it’ll soon wear off.

Importantly, when you do drive your car for the first time (when government guidance suggests you can), give it a good run for half an hour or so to make sure the 12v battery is fully charged. Giving the engine time to run up to temperature will also be beneficial.