Motorists considering their next car purchase should be considering hybrid models which are proving more reliable than petrol and diesel-powered motors, according to a comprehensive poll of vehicle owners.
With sales of new diesel, petrol and hybrid cars due to be banned in 2035 under current government directive, the next vehicle for many buyers will be their last to feature an internal combustion engine.
Watchdog Which? surveyed over 55,000 UK drivers and found that petrol hybrid cars are the most dependable – and therefore will likely last motorists the next decade.
Hybrid longevity: Which?’s car reliability report suggests a petrol-hybrid car could be the best choice of vehicle between now and 2035, with these models being the most dependable to run
While two power sources – a battery and electric motor supporting a petrol engine – seem like a recipe for a reliability nightmare and the potential for enormous repair bills, Which’s reliability survey said that could not be further from the truth.
The result of it’s latest survey of 55,833 individual new and used models discovered that petrol-hybrid cars are the most reliable fuel type.
Despite some variations over the years, conventional ‘self-charging’ hybrids have consistently outperformed both conventional petrol and diesel cars.
Less than three per cent of conventional hybrid car owners who took part in the poll said they had to seek mechanical assistance for issues with their vehicles – an exceptional result.
Models registered six years ago were found to have average reliability scores exceeding 95 per cent, suggesting there’s plenty of longevity in hybrid-car ownership.
By comparison, around six per cent of petrol, 10 per cent of diesel and 10 per cent of electric car drivers suffered a problem with their motors over the same time period, across all brands and car types.
The consumer watchdog’s figures, taken from owners of thousands of UK cars, show that plug-in petrol hybrids are consistently more reliable than other fuel types
Plug-in petrol hybrids (PHEVs), which have larger battery packs to allow for extended electric driving, are not quite on a par with standard hybrid models.
Which? believes this is because conventional hybrid cars have been around much longer than PHEVs, with the likes of the Toyota Prius dating back as far as the turn of the century.
With diesel now very much an ‘enemy of the state’ and sales progressively in decline – down over 60 per cent so far in 2020 and making up fewer than two in five new cars – motorists are turning their attention elsewhere and increasingly likely to buy hybrids.
Which? says it’s plug-in hybrid and hybrid cars – collectively representing one in ten new cars bought this year – that could be the best choice if you want you next vehicle to last until the 2035 ban.
Why would a hybrid be more reliable than petrol or diesel car?
Despite the complexities of two motors working in harmony, hybrid cars are mechanically simpler than conventional petrol or diesel cars, which reduces the likelihood for problems, Which?’s expert team of car testers claim.
For instance, there’s no clutch or starter motor, the CVT gearbox fitted to most models never disengages, so is more resistant to wear and the assistance of the electric motor means the petrol engine is less stressed and doesn’t need working as hard, increasing longevity.
The most complicated part of hybrid systems are the power inverter, which is a non-moving part, and the software that controls it all.
Harry Rose, editor at Which?, said: ‘It’s great to see so few people reporting issues with their petrol hybrid car.
‘Despite the complexities of two motors working in harmony, they are mechanically simpler than conventional petrol or diesel cars, which is good news for motorists as it reduces the likelihood of problems.
‘While our research shows electric cars and plug-in hybrids are still less dependable than other fuel types, we expect to see their reliability improve as these markets establish themselves.
‘Thanks to more challenging CO2 regulations, we’re seeing more choice and in the future, we will have a lot more models to report on.’
The market choice available today is fairly extensive.
Commonly, the most likely model you’ll think of when you consider hybrids is the Toyota Prius, which was the first dual-power model to become widely popular since it launched in the UK in 2000
French brand Renault has recently unveiled plug-in hybrid version of the Captur crossover (left) and a conventional hybrid Clio (right)
Hybrid Lexus models – like the RX450h pictured – were among the most dependable electrified cars in another reliability survey conducted by What Car?
Renault has recently launched two compact hybrids, including a self-charging Clio alongside a PHEV Captur.
Toyota also offers a range of vehicles with the dual-motor Yaris, RAV4, Corolla and Prius among the most popular hybrids on the market.
Sister brand Lexus sells hybrid versions of every model in its range, including the IS, RX, NX and CT – all of which were rated among the ten most dependable electrified cars in What Car?’s recent reliability poll.
Mitsubishi’s Outlander PHEV has been one of the most popular hybrids in the UK in recent years, though the Japanese manufacturer plans to pull operations from Europe in the coming months as it looks to focus on other markers where it sell more cars.
Different types of hybrid cars
These use a small electric motor alongside (but not independent of) a combustion engine. How it does so depends on the model.
Some give extra power under acceleration; others let the engine be turned off when braking or coasting to save fuel.
With much smaller batteries than conventional hybrids, you can’t drive one on electricity alone. So official CO2 emissions aren’t as low.
Conventional ‘self-charging’ hybrids
‘Self-charging’ hybrids are petrol cars with a battery charged using energy recuperated under braking or when coasting.
This powers an electric motor that can take over or help a petrol engine when it’s at its least efficient (eg when setting off), sharply cutting fuel use in town.
They can be driven emissions-free, but only at low speeds for about a mile.
Plug-in hybrids (PHEVs)
As a halfway house between petrol and full electric cars (EVs), PHEVs have smaller batteries than EVs but can still be driven on electric power alone, normally for around 20 to 40 miles.
You’ll need to plug them in regularly for best economy, but most models can also use the engine to charge up the battery. When the battery is depleted, PHEVs work like a full hybrid.
‘Hybrids aren’t as green as you think’, warns eco campaign groups
While hybrids might be the most reliable, green groups have warned that they’re not as economical as manufacturers would lead you to believe.
Environmental campaigners have concerns that advertised fuel economy and emissions figures – which are used online and in TV adverts promoting the vehicles – are misrepresentative, as highlighted by a new market review.
For instance, the Outlander PHEV, has a claimed combined fuel economy of 139 miles and a quoted range of 28-mile range in electric mode only.
These figures are based on laboratory test cycles and are almost impossible to replicate on the road.
Mitsubishi claims in its advertising that the Outlander PHEV has a claimed combined fuel economy of 139 miles and a quoted range of 28-mile range in electric mode only. In reality, these figures are not achievable
A recent Guardian report found that many of the popular plug-in hybrids don’t maximise the use of electric power due to limitations with the technology.
It reviewed models that feature zero-emission driving modes, which when selected are designed for the vehicle to operate only using electric power without switched to the supplementary petrol engine.
The report found that many of these modes switch off if the conditions are not suitable for the vehicle or technology.
One of the biggest issues is cold weather, something that has greater significance in Britain at this time of year.
Popular models have been found to deviate from using their electric-only modes to the petrol engine when temperatures drop, even when the onboard battery is fully charged.
This is partly because the batteries need to warm up in order for them to send power to the electric motors.
This is the case for models such as the Volvo XC90 Twin Engine, Mercedes-Benz E300 and Kia Niro Plug-In Hybrid, the report states.
The latter also switches to petrol power when the windscreen de-mister is switched on, according to Transport & Environment.
And when users choose to turn on the cabin heating, this can also trigger plug-in vehicles to switch to their internal combustion engines.
Greg Archer from campaign group Transport & Environment says manufacturers are misleading customers about the green credentials of their hybrid models
Range Rover’s p400e and Porsche’s Cayenne E-Hybrid were also found to use their petrol internal combustion engines if more power is required than the electric-only supply can provide.
Specific electric driving modes in BMW’s range of plug-in hybrids – including the Mini Countryman Plug-in Hybrid – also have speed limits. When these are reached, the power switches from electricity to petrol.
The market-wide review also found that Mitsubishi’s Outlander would instantly revert to the petrol engine when a driver uses adaptive cruise control or if the battery gets too hot or too cold in extreme conditions.
A spokesman for Mitsubishi responded to The Guardian’s report, stating: ‘The vast majority of owners we surveyed use their Outlander [plug-in hybrid] as it was engineered and are enjoying a lower carbon footprint and lower running costs as a result.’
Greg Archer, UK director at Transport & Environment, said one leading carmaker – which he didn’t reveal – ‘is conning its customers’, after it had been contacted by an unhappy owner of one of its plug-in hybrid.
He has backed the UK government’s decision to ban the sale of all hybrid cars in-line with new petrol and diesels from 2035 and also the removal of grants to help drivers purchase them at reduced rates.
He told The Guardian: ‘A [plug-in hybrid] is not driving with zero emissions if it switches on its engine when the driver de-mists the windscreen.
‘This is another example of carmakers attempting to mislead their customers about the real emissions from their car.’
BMW confirmed this month that it has developed new technology for its hybrid cars so that they automatically revert to full-electric model when they enter low emission zones, such as the London ULEZ.
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