Hybrid battery problems: How they affect petrol-electric cars

Hybrid battery problems

Toyota Prius started the petrol-electric revolution (Picture © Toyota)

Hybrid battery problems courtesy of wiring faults are becoming a common cause of breakdowns with the increasingly popular petrol-electric cars. The old cliché is that modern cars have more computing power than the first Apollo moon rockets. It’s true but it also means they have more wiring. And the more complex the electronics, the greater the capacity there is for something to go wrong. Here we look at how battery problems can afflict cars that use electricity to supplement petrol or diesel power.

What kind of breakdowns hit hybrid cars?

Hybrid cars use complicated electronics to switch between battery power and the internal combustion engine. It’s this control module that can cause reliability problems. The only hybrid model in the UK Reliability Index top 100 most dependable cars is the Toyota Prius. In the US, independent reliability tester Consumer Reports claims that Tesla’s Model S had below average reliability.

Do hybrid cars have a conventional 12-volt battery?

Nick Reid, Green Flag’s head of automative technology explained: “Cars like the Toyota Prius will effectively have two batteries. There’s the high-powered battery that propels the car, and this has a 12-volt battery connected to it. This smaller battery will run all the equipment such as the audio system and electric windows. It needs replacing after five, six or seven years, like the battery in any other car. When we deal with a 12-volt battery problem on a hybrid car, we don’t go anywhere near the high-powered battery.”

How long do a hybrid’s propulsion batteries last?

Theoretically the batteries on a hybrid should last the life of the car. Toyota claimed: “The Prius battery (and the battery-power management system) has been designed to maximize battery life. In part this is done by keeping the battery at an optimum charge level – never fully draining it and never fully recharging it. As a result, the Prius battery leads a pretty easy life.

“We have lab data showing the equivalent of 180,000 miles with no deterioration and expect it to last the life of the vehicle. Since the car went on sale in 2000, Toyota has not replaced a single battery for wear and tear.” However, independent repairers claim there have been problems with hybrid propulsion batteries. Interestingly they believe repairing the batteries, rather than replacing them is the most reliable and cost-effective action. You can have the batteries on a first generation Toyota Prius rebuilt for around £700.

Why are the number of hybrid battery problems and breakdowns increasing?

Quite simply, there has been an explosion in the number of hybrid cars sold in the UK. And the more of something on the road, the more breakdowns there will be. Society of Motor Manufacturers and Traders EV figures show that 44,580 hybrid vehicles were sold in the UK in 2015, a 20 per cent increase on the year before. There are more than 10 times as many on the road as in 2012. This has been fuelled by demand and an increasing number of manufacturers supplying hybrid cars.

What exactly is a hybrid car?

Broadly speaking hybrids combine petrol or diesel engines with battery powered motors. The electric motor powers the car at low speeds and supplements the internal combustion engine when extra acceleration is needed. The electric motor is generally charged up by harnessing the kinetic energy that goes to waste when a regular car slows down or brakes. Plug-In Hybrid Electric Vehicles give owners the option of fully charging the battery via mains electricity.

7 comments on “Hybrid battery problems: How they affect petrol-electric cars

  1. Myra 01/02/2016 11:35 AM

    I run a V6 Lpg/petrol engine in a Freelander. My son feels I ought to sell that and buy a bog standard petrol car, since the latest hybrids are way out of my price range. Do the hybrids hold their prices well? I have an outside weatherproof electric socket for the caravan, is this suitable for charging hybrids, or do they require specialist charging equipment?

  2. James Foxall 18/02/2016 10:50 AM

    Hi Myra. It depends on the hybrid as to whether they hold their value well. As for charging them, most hybrids charge up using the engine. Plug-in hybrids also charge using mains sockets. Most come with two power cables; one with a normal three-pin plug on it; one with a special adapter for fast chargers. Hope this is helpful.

  3. Iain Ansell 25/08/2016 2:23 PM

    …. also, plug-in hybrids (PHEV) are great if you do a lot of short journeys… for intance, if you had the mitsubushi outlander phev, you could do about 20 miles without using petrol at all!! so if you rarely do more than that, you’d hardly use any petrol- plus it is AWD like your freelander- and spacious..

  4. john graver 18/12/2017 11:10 AM

    at what speed can you do the electric miles do you drive normally or are you a pain in the butt because you are driving slowly to achieve those 20 miles

  5. Nigel 22/02/2020 1:53 AM

    The main issue with Hybrid cars and batteries, is the auxiliary battery. A deep cycle 12V AGM battery. That is needed to power up the computers before a hybrid car can be started.
    Hybrid cars do not have an alternator. The 12V aux battery is charged from the High voltage traction battery via a DC to DC converter. Whilst the car is running.
    If volts are too low on aux 12v battery car will not start. If this happens you can so call jump start a hybrid car by connecting to a terminal in the fuse box and to earth and applying voltage . All this does is give enough voltage to boot up the computers to start the car.
    The aux 12V battery runs lights, computers, radio, electric windows, central locking and alarm. It is under permanent drain and can die if car is not driven for a while, or its cold.

  6. James McGinlay 06/05/2020 9:51 PM

    Can I use a battery charger on my 2015 Auris hybrid excel 1800 to top up my 12 volt battery from the terminal in the fuse box

  7. Barry Wilson 02/11/2020 9:45 AM

    Don’t know if it helps but my hybrid RAV 4 wouldn’t start & the AA guy firstly charged the battery under the bonnet which didn’t take long & then charged the one in the boot with a portable battery booster.

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