Electric car charging mega test: do EVs really charge as quickly as they say?

Auto Express

2 days ago

Charging is probably the most contentious aspect of electric motoring. When you hook up your electric car to an ultra-rapid and powerful DC charger, why doesn't it consistently hit the peak rate advertised? And why are many motorists waiting more than the promised 30 minutes to refuel their battery from 20 to 80 per cent? Advertisement - Article continues below
Many assume that the charger is to blame for causing the reduced rates, not the car. Gridserve – a major chargepoint operator – vows that's not the case. To find out once and for all, Auto Express took 10 different EVs to Gridserve's charging hub in Braintree, Essex, to discover the truth about fast charging.
We also sought expert advice from the company's Technical Director, Pete Bishop, on each car's performance, looking into not only the charging rate, but how it is distributed over the time a car is connected.
To understand what we are looking at here, it's important to know that there are various factors that determine how fast and effectively an EV's battery can accept a rapid charge; the most crucial is the ambient temperature. Most EV batteries prefer to charge at between 20 and 30 degrees Celsius.
But resistive losses can cause the cells to heat up as energy is dissipated, potentially resulting in heating of the battery. At higher states of charge, the rate at which the cells can accept energy reduces, so the battery management system reduces the charge current to prevent irreparable damage to the battery. Skip advert Advertisement - Article continues below
The result of this is that you have to stay plugged-in for longer, but the point at which the car does this is largely down to built-in software; hi-tech, continuously variable algorithms will Advertisement - Article continues below
use several measurements to optimise charge rates in line with optimum battery voltage and temperatures, while so-called look-up table methods will adjust the rate of charge as certain criteria – such as the battery capacity – are met.
To demonstrate each car's charging curve and find out whether makers might not be telling the full story of their cars' capabilities, we devised a test under strictly controlled conditions.
Outside, the ambient temperature was around 13-14 degrees (just below optimum) and none of the cars were preconditioned before charging; not all models provide the option to do this manually, so it was the fairest way. Besides, it's something many of us often forget to do, anyway.
Furthermore, given that most makers quote different charging times, we simply ran all the cars down to a similar level the day before then timed how long it took to add 60 per cent to the battery – also taking an average charging speed during this time – as well as how long it took to get from 80-100 per cent. Although experienced EV drivers know not to charge beyond 80 per cent, this illustrates to new owners why you shouldn't charge all the way to full at a public charger. Advertisement - Article continues below Skip advert Advertisement - Article continues below
Each had its own charger, capable of charging at up to 350kW; Gridserve kept an eye on things to ensure their chargepoints were capable of delivering the full amount of power. This meant it was up to each of the cars themselves to choose the level of output – but which fared best? Battery size: 82.5kWh Claimed peak charging rate: 150kW Initial state-of-charge: 15% Achieved peak charging rate/duration: 123kW/5 minutes Adding 60% to battery: 32 minutes Avg charge rate to 80%: 104kW Charge time 80-100%: 56 minutes (99%)
The BYD Seal got off to a rather shaky start, likely due to the battery management system trying to work out an appropriate level of charge after the car had been left sitting for a while. After this, the BYD gradually ramped up its charge rate and held its maximum for a good amount of time, maintaining an average of more than 100kW throughout the first 60 per cent added.
After this, however, you can see the charge rate slowly staircasing downwards, dropping to just 48kW at around 85 per cent – likely a threshold BYD has pre-programmed into the car's algorithms. Charging from then on at such a low rate, the BYD took an awfully long time to top up to full – almost double the time it took to get to 75 per cent, in fact.
Strangely, the Seal refused to charge up to a completely full battery, stopping at 99 per cent before cutting off current from the charger. We asked BYD why this might be the case, but the Chinese firm wasn't able to provide us with any additional insight.
The BYD quickly peaks before dipping back down again; our charging expert believes this is a case of the car requesting a higher power output, based on values from when the car was sitting static with a cold battery.
Most impressive about the BYD's charge curve is how it maintains its maximum rate for what is a decent amount of time – roughly five minutes in this case. Once it settled into a steady charge rate, it keeps charging at over 120kW all the way until it hits around 60 per cent capacity.
After hitting 60 per cent, the BYD's rate of charge dips significantly. Such a sharp drop-off is indicative of the BYD's look-up table algorithm which adjusts the rate of charge depending on how much is in the battery. This means charging is less efficient at higher capacity.
For the remainder of the charge session, the BYD truly took its time, continuing to staircase downwards and charging at well below 50kW from roughly 85 per cent, taking almost an hour to fill from 80 per cent. It didn't reach 100 per cent charge, either, stopping just shy.
'The staircasing you see on the BYD's graph is indicative of a simple, look-up table algorithm. After a slightly erratic start, it appears very contained after that, maintaining a consistent rate of charge until it throttles back down after presumably reaching the pre-programmed temperature limit.' Advertisement - Article continues below Skip advert Advertisement - Article continues below
Latest BYD Seal deals Battery size: 44kWh Claimed peak charging rate: 100kW Initial state-of-charge: 15% Achieved peak charging rate/duration: 69kW/3 minutes Adding 60% to battery: 34 minutes Avg charge rate to 80%: 57kW Charge time 80-100%: 47 minutes
The Citroen e-C3 is the cheapest car here, starting from just over £22,000, so it's no surprise that it incorporates the simplest battery management system. Like the BYD, the Citroen employs a look-up table algorithm, although unlike that car, the e-C3 took quite a while before it reached its peak rate.
After such a slow build-up, the Citroen didn't get that close to official stated figures and even then only held at that point for three minutes. After this, it began throttling downwards in a step-by-step fashion, taking 10 minutes longer than Citroen's claimed 20-80 per cent charge time to add 60 per cent to the battery. Nevertheless, just over half-an-hour isn't bad when most people using rapid charging will likely be popping to the loo and grabbing a coffee before heading off again.
Most disappointing was the time it took to add the final 10 per cent; while 80-90 per cent only took 11 minutes, we had to wait a whopping 47 minutes for the e-C3 to finish charging.
The Citroen didn't peak immediately. Like the BYD, the e-C3 initially requested a bit more power than the limits set by its battery management system, with the charge rate dipping by around 10kW for a few minutes afterwards.
After that initial spike, the e-C3 gradually ramps up its power delivery step-by-step, before holding at its peak rate of 69kW charging for just three minutes, which is disappointing given how that figure is still only seven-tenths of what Citroen says is possible.
The Citroen's look-up table algorithm is clear to see, as the charge rate drops down following its peak, finally coming to a plateau at around 90 per cent full. Which isn't awful considering that the Citroen had only started charging 45 minutes earlier, but it's not as fast as claimed.
From 80 per cent, the Citroen took a further three quarters of an hour to add just over 4kWh worth of charge, meaning it was topping up at just eight-and-a-half kilowatts, or by this stage, only slightly more than you'd get using a home wallbox – making a fast charger redundant.
'Like the BYD, the Citroen uses a look-up table algorithm for its battery management system, with very clean steps. This example is definitely in the simple category – a cheaper car can mean a cheaper system. It only maintains its maximum charge for a couple of minutes, but the aim is the best performance possible for the lowest cost.' Advertisement - Article continues below Skip advert Advertisement - Article continues below
Latest Citroen e-C3 deals Battery size: 79kWh Claimed peak charging rate: 187kW Initial state-of-charge: 9% Achieved peak charging rate/duration: 187kW/2 minutes Adding 60% to battery: 20 minutes Avg charge rate to 80%: 154kW Charge time 80-100%: 15 minutes
The Ford Capri was one of the better-performing cars on the test, thanks largely to its sophisticated continuously variable battery management system designed with Volkswagen. It reaches its peak rate quickly, which matched the maximum stated by Ford, at 187kW.
Following this, the Capri stays above the stated maximum charging rate for eight minutes before beginning its gentle descent, averaging well over 150kW throughout the duration of the 60 per cent top-up. In fact, it's only once the Capri hit 70 per cent that it finally dipped below 100kW, or what is deemed to be the threshold for ultra-rapid charging.
Throughout the final stretch of the charge, the Capri maintained a strong charging rate, with the steeper slope right at the end likely indicating the car hit its voltage limit at around 95 per cent. Nevertheless, a strong performance is seen here, topping up the final 20 per cent in less time than some models took to complete the first portion of the test.
The Ford peaks relatively quickly – within just a couple of minutes, in fact – and was one of the few cars in this test to hit or get close to the manufacturer's claimed maximum rapid charging rate, even beating it.
After reaching its peak, the Ford hangs on remarkably well. It stays within one or two kilowatts of its maximum rate for eight minutes before it begins to roll off – the reasoning for which, our expert suspects, is due to the battery temperature limits being reached.
The gentle curve shown in the graph illustrates the Capri's continuously variable charging algorithm, which can adjust charge speeds depending on things like heat and voltage, as well as the state of charge. It's a sophisticated system and its performance in this test shows its clear advantages.
Towards the very end, the Capri's curve gets much steeper, but the rate of charge remains impressive, topping up from 80-100 per cent in around half the time many other models took. The Ford spent less than 45 minutes plugged in altogether and left the site with a full battery.
'The charge curve of the Ford indicates a sophisticated system that's constantly trying to optimise the charge performance against thermal limits. It's encouraging that the Capri hit its claimed charging rate for a decent amount of time, while maintaining a reasonable power all the way through the rest of the cycle.' Advertisement - Article continues below Skip advert Advertisement - Article continues below
Latest Ford Capri deals Battery size: 78kWh Claimed peak charging rate: 135kW Initial state-of-charge: 16% Achieved peak charging rate/duration: 128kW/2 minutes Adding 60% to battery: 27 minutes Avg charge rate to 80%: 117kW Charge time 80-100%: 28 minutes
Kia has designed the EV3 with a 'splash-and-dash' mentality and that is evident from its charge curve, which sees the car get very near its peak charging rate and hold steady near that point for around 20 minutes, adding roughly 50 per cent to the battery in that time.
Then, almost as the level of charge approaches 70 per cent, the EV3 takes a dip, and then a nosedive – likely due to either hitting a voltage or temperature limit. Even so, the EV3 maintains an average of 117kW during the test to add 60 per cent, which isn't far away from the peak speed quoted by Kia.
Following this point and after dropping back to just under 80kW, the charge rate begins a much gentler decline, on a curve that's similar to that seen on the Ford or Tesla. The curve becomes much shallower right at the end after hitting 85 per cent – a threshold that's likely to have been preset by Kia itself within the battery management system.
The Kia quickly reaches its maximum rate of 128kW – this is only marginally less than what the Korean firm states is possible and is impressive for what is a mainstream EV towards the more affordable end of the spectrum.
After hitting peak speeds, the Kia EV3 maintains a high rate of charge, demonstrating how it has been designed for quick 15-minute-or-so charge sessions to suit its target customer. It's aimed at getting as much juice into the battery over the shortest possible period of time.
After a while, the EV3's charging speeds fall off a cliff, likely due to it reaching either a voltage or thermal limit. Still, by this point the battery has already reached roughly 70 per cent capacity, which should still be fine for that 'splash-and-dash' mentality, and ideal for a quick getaway.
After plateauing at 30kW until the car reaches just over 90 per cent, charge speeds began to drop exponentially until the EV3 was fully charged, going as low as 4-5kW towards the very end of the cycle, with the final 20 per cent charge taking longer than the bulk 60 per cent.
'The Kia EV3 is an interesting example of how the manufacturer has optimised the system for getting as much power into the battery as quickly as possible, but at the expense of a longer experience. It eventually hits the thermal limit and slows charging, with a graceful decline that ends at around 85 per cent.' Advertisement - Article continues below Skip advert Advertisement - Article continues below
Latest Kia EV3 deals Battery size: 73kWh Claimed peak charging rate: 130kW Initial state-of-charge: 16% Achieved peak charging rate/duration: 123kW/3 minutes Adding 60% to battery: 38 minutes Avg charge rate to 80%: 86kW Charge time 80-100%: 74 minutes
The Peugeot E-3008 was one of the more disappointing performers in this test, taking more than 10 minutes to reach its peak rate – a figure that was significantly down on the capability that the French manufacturer claims.
After reaching this peak, the E-3008 immediately began to throttle back, only hovering around that point for three minutes or so. This downward staircasing continued throughout the majority of the rest of the charge cycle, with the rate spending very little time above 100kW. Peugeot was keen to point out that charging in colder conditions or starting from a different point than 20 per cent could lead to disrupted performance, but the E-3008 nevertheless stands out compared with the other cars in this test.
After an hour of charging, things slowed down even further, with the Peugeot winding back all the way down to just 13kW, taking well over an hour to charge the E-3008's rather large 73kWh battery from 80-100 per cent.
The Peugeot doesn't reach its peak charging speed all that quickly. In fact, it's one of the slowest cars here in this regard. However, after what is a relatively stable climb it then reaches a top charging rate of 123kW.
It may dip down slightly after a short while, but the Peugeot still maintains a relatively decent charging speed for several minutes as it tops up. That said, once the battery reaches 45 per cent capacity, the rate at which it charges starts to drop significantly, by roughly 30kW.
The sudden drop in charging rate is just the start of what then becomes a rapid staircasing down as the battery management system reads the charge, with the E-3008 topping up at just over 50kW once it hits 73 per cent capacity, thus completing the target 60 per cent top-up.
It becomes a bit of a slog towards the end, with the Peugeot dropping its charging rate down to around 20kW at 90 per cent, tailing off to well under 10kW for the very final stages of the charge cycle – it ended up taking almost an hour to get the battery from 95 to 100 per cent.
'After ramping up, the Peugeot drops off a cliff after nearly no time at all. It didn't get that near the maximum rate, so it sounds like Peugeot is either overstating what it can do, or it gets there under such optimised laboratory conditions, that – as an owner – you're never going to see in the real world.' Advertisement - Article continues below Skip advert Advertisement - Article continues below
Latest Peugeot E-3008 deals Battery size: 97kWh Claimed peak charging rate: 320kW Initial state-of-charge: 14% Achieved peak charging rate/duration: 282kW/3 minutes Adding 60% to battery: 15 minutes Avg charge rate to 80%: 243kW Charge time 80-100%: N/A (stopped at 93%)
It's perhaps not surprising that Porsche would develop and produce one of the most sophisticated and effective battery management systems, but what is perhaps most impressive is how well the Taycan does at rapidly charging its huge cell.
Despite the German brand claiming a maximum 320kW rate for its EV, the Taycan peaked at just over 280kW and stayed there for only a few minutes. Nevertheless, the Porsche throttled back slightly and was able to maintain a strong speed of 250kW for around 10 minutes, topping up the battery to about 65 per cent before the management system kicked in and began pulling things back further.
Most impressive, however, is that even towards the very end, the Taycan never dipped below 50kW, showcasing the best of German engineering. On the other hand, a warning for a 'battery isolation fault' did stop the charge at 93 per cent and showed that a premium badge doesn't stop the Taycan from having faults.
Reaching its peak speed almost instantly, the Taycan never got close to the figures that Porsche claims; in fact, the electric sports saloon was charging at around 40kW slower than stated by the manufacturer.
Like the Kia EV3's, the Porsche's battery management is evidently designed for quick refuelling, with it holding the rate of charge at a relatively high point until it reaches its Advertisement - Article continues below Skip advert Advertisement - Article continues below
limits, in order to get as much electricity into the battery as possible in a short time.
Here, the Porsche's charge rate begins to slow down, although the decline isn't anywhere near as severe as that which we saw on the Kia EV3. Also, it's only after the Porsche's battery hits 80 per cent capacity that charging speeds start to fall below 100kW.
It took just over 10 minutes for the Porsche to reach 93 per cent, after which a battery isolation fault issued by the car forced the charger to stop issuing power; Porsche is yet to tell us what the cause of this may have been. However, it was still an impressive overall performance.
'The Porsche is another good example of how to optimise a car to take as much charge as possible in a short space of time. It's almost straight in, holds a high level for a long time then doesn't go off a cliff. The Taycan constantly tries to do the best it can with the constraints of battery temperature and state of charge.'
Latest Porsche Taycan deals Battery size: 52kWh Claimed peak charging rate: 100kW Initial state-of-charge: 11% Achieved peak charging rate/duration: 87kW/2 minutes Adding 60% to battery: 26 minutes Avg charge rate to 80%: 65kW Charge time 80-100%: 34 minutes
The Renault 5 may only be a few hundred pounds more expensive than the Citroen e-C3, but as we can see from its graph, it boasts a much more sophisticated battery management system using a continuously variable algorithm, similar to the Volkswagen and Toyota. Advertisement - Article continues below Skip advert Advertisement - Article continues below
However, the Renault doesn't reach its peak charging speeds all that quickly; it wasn't until the R5 had been charging for 10 minutes that it finally hit 87kW, which is still 13kW below the modest maximum rate stated by the brand. It didn't hold onto it for that long, either.
Nevertheless, the Renault 5 kept to its promise of 15-80 per cent top-ups in less than half an hour and generally didn't slow down the rate of charge all that much until it hit that threshold. Right at the end you can also see the Renault generating a staircase-style effect on the graph, indicating that at higher levels of charge the car switches to a more rudimentary algorithm – we assume this to preserve long-term battery health.
As was common with several cars in our test, the Renault's battery management system requested too much power at first, reducing its charge rate to under 60kW before then slowly rising in an inconsistent fashion.
The peak speed achieved by the R5 during our test was only 87kW, which is 13kW below Renault's claims. While it's more than the similarly priced Citroen achieved, which also shares a fairly low claimed 100kW maximum, it isn't quite what Renault says it should be capable of.
After reaching its peak speed, the Renault 5 throttles back creating a gradual slope downwards. This means charging rates don't slow down that quickly, meaning the R5 hit the 60 per cent top-up target within Renault's stated time period despite never reaching 100kW.
As it approaches full capacity, the R5's battery management system switches to a look-up table algorithm, adjusting the rate of charge every three per cent or so. The steps are steep at first, although at the end the rate plateaus again, taking almost 10 minutes to get from 99 to 100 per cent.
'The Renault may be an inexpensive EV like the Citroen, but it's doing a better job in its battery management – although, it doesn't sustain power for long. It doesn't quite reach maximum power, but it does have a long, shallow curve after its peak. After this, it goes from a variable rate to a standard staircase output.' Advertisement - Article continues below Skip advert Advertisement - Article continues below
Latest Renault 5 deals Battery size: 75kWh Claimed peak charging rate: 250kW Initial state-of-charge: 14% Achieved peak charging rate/duration: 145kW/1 minutes Adding 60% to battery: 30 minutes Avg charge rate to 80%: 103kW Charge time 80-100%: 63 minutes (99%)
It's no surprise that Tesla – a brand that has been making electric cars since 2008 – would incorporate some of the most hi-tech battery management algorithms within the industry. It is a shock, however, to see that the Model Y wasn't able to achieve anything close to what Tesla claims during our test.
Tesla tells us that the reason for this is that we had not pre-conditioned the car's battery, yet this was the case for all cars in the test – many of which were able to achieve their maximum rates. After reaching roughly 100kW less than Tesla claims is possible, the Model Y began reducing its charging rate through what appears to be a continuously variable algorithm, similar to the likes of the Ford, Porsche and Renault.
Unlike those cars, the Model Y took what felt like an age to fully charge, dropping down to under 50kW only minutes after topping-up by 60 per cent. It also didn't manage to completely fill its battery, cutting out just beforehand at 99 per cent charge.
The Tesla was one of the fastest cars on the test to hit its peak speed – in this case being 145kW. It only held it at this point for a minute, though, and even this was over 100kW less than what Tesla claims is possible.
Tesla has had years to refine its battery-management technology and you'll see from this steep curve that the Model Y uses a continuously variable system, rather than a more rudimentary look-up table algorithm to determine charging speeds.
Tesla says that a 20-80 per cent top-up should take around 20-25 minutes at one of its Superchargers. At a similarly powered non-Tesla EV charger, shared with the rest of the cars on test here, the Model Y took roughly 30 minutes to get from 14-74 per cent.
The Model Y took just over an hour to charge its battery to full from 80 per cent. For much of that time, towards the upper capacity of the battery, it was charging at rates as slow as just one kilowatt before finally cutting power completely at 99 per cent capacity.
'Tesla has been in the game a long time and has a pretty sophisticated battery management system, so its cars tend to reach peak power quickly – although this didn't get close, nor hold it for very long. Otherwise, it's well controlled and it's clear with Tesla's battery longevity that it's doing well at remaining in a safe operating area.' Advertisement - Article continues below Skip advert Advertisement - Article continues below
Latest Tesla Model Y deals Battery size: 64kWh Claimed peak charging rate: 150kW Initial state-of-charge: 14% Achieved peak charging rate/duration: 147kW/1 minute Adding 60% to battery: 26 minutes Avg charge rate to 80%: 96kW Charge time 80-100%: 29 minutes
Toyota may be lagging behind in the EV game, but the bZ4X put on a decent showing in our test, getting close to its claimed peak charging rate after a couple of minutes ramping up – but only for about a minute or so.
After this point, the Toyota immediately began throttling back, but it was able to stay above 100kW for about 10 minutes – the time most people need to pop to the loo and maybe grab a coffee at a service station. In this time, the bZ4X almost reached 50 per cent battery capacity, taking a further 15 minutes to finish the 60 per cent top-up portion of our test.
Things got pretty sluggish towards the end, though, taking roughly 29 minutes to get from 80-100 per cent charge. This is mostly due to the fact that once the bZ4X hit 99 per cent, the charging speed fell off a cliff almost entirely, going down to less than 15kW and taking almost six minutes to add the final one per cent.
The Toyota took a couple of minutes to reach its peak – it didn't demand too much electricity then drop power delivery like the Renault and BYD, though. Once it got to its peak, it was within a few kW of Toyota's claims.
The bZ4X only hit its peak rate for a minute before plunging down a relatively steep curve, dipping down below 100kW roughly five minutes later. The high charge rate up until this point does mean that it is sitting at around 50 per cent capacity by the time it gets to this stage, though.
After a while, the bZ4X's curve begins to flatten out somewhat, quickly dipping to below 50kW shortly after the Toyota reached the milestone figure of 60 per cent of capacity added to the battery. But in a fast-charging scenario over a 10-minute period, it did add charge quickly.
You can see that, towards the final minutes of the bZ4X's charging session, it begins to create something of a staircasing effect as the charge rate keeps ramping down to a slower level; the final five per cent of its charging takes over 12 minutes to complete.
'The Toyota is very well controlled; it doesn't staircase up and is updating its charge current every few seconds to get the best it can. However, look how short Advertisement - Article continues below Skip advert Advertisement - Article continues below
a time it spends at its peak – it does get pretty close to the claimed peak rate, but probably wouldn't have stayed for much longer, even if pre-conditioned.'
Latest Toyota bZ4X deals Battery size: 86kWh Claimed peak charging rate: 200kW Initial state-of-charge: 12% Achieved peak charging rate/duration: 200kW/3 minutes Adding 60% to battery: 21 minutes Avg charge rate to 80%: 156kW Charge time 80-100%: 16 minutes
Both the Ford Capri and Volkswagen ID.7 share VW Group's MEB platform, so given that the former performed so well in this test, we weren't surprised to see similar results for the latter – even if it boasts a slightly larger battery pack.
The Volkswagen maintained its peak speed for roughly the same amount of time as the Ford, and both also managed to hit the manufacturer's claimed maximum. The general curve on the graph is similar to the Ford's as well, with the VW holding onto a decent rate for around five minutes before beginning a shallow descent.
In fact, it isn't until the VW's battery hits 76 per cent capacity – slightly over that of a charge session to add 60 per cent – when the rate drops below 100kW. From here, the VW's continuously variable algorithm maintains a smooth curve until capacity passes 92 per cent, when speeds begin dropping. That said, the 80-100 per cent charge was completed in 16 minutes, which is less than a quarter of the time than the smaller-battery Tesla or Peugeot took.
It took just over three minutes for the Volkswagen ID.7 Tourer to reach its maximum rapid charging rate of 200kW; not only did it hit VW's claims, but it also maintained that rate for a couple of minutes.
Volkswagen has tuned its battery management system well to hold onto a high rate of charge for a decent amount of time, so it isn't until the ID.7 hits around 50 per cent of its total capacity when speeds start declining at any notable rate. Even then, it's a steady and regulated drop.
The shallow slope downwards means the ID.7 is able to keep charging at over 100kW roughly until it surpasses three quarters of battery capacity, having added more than 60 per cent's-worth of energy by this point. This is particularly useful for those who need to cover long journeys frequently.
Even right at the end, the Volkswagen doesn't slow down its charging rate all that much; the slowest we see it charging at all is at 35kW. Throughout the entirety of the charge (not just the 60 per cent portion) we see an impressive average speed of 123kW.
'The Volkswagen shows similar results to the Ford and they're almost certainly using a very similar battery chemistry and management system. After a quick ramp up, there's a dip near the beginning of the charge, but it then does a good job of staying over 100kW for a large proportion of the time.' Advertisement - Article continues below Skip advert Advertisement - Article continues below
Latest Volkswagen ID.7 deals
If you haven't ever charged an electric car, you might be shocked to see how many of the cars tested didn't hit the claimed maximum charge rate – and how even fewer held at this point for more than a minute or so.
In fact, the majority of the models we tested averaged around two thirds – or less – of the manufacturer's claimed rates while adding 60 per cent of capacity to their batteries, despite still reaching estimated charge times.
Several manufacturers have told us that the real reason their cars didn't reach the stated targets is because we didn't pre-condition the batteries. However, this was done to create a level playing field for all the cars; and given how some models were able to get there without additional steps, it would be fair for drivers to expect that this to be the same across the board. The difference between the way EVs charge is as stark as it is surprising.
Ultimately, this test is more useful for illustrating how the maximum charge rate of a car really is exactly that – a maximum – and is far from telling the whole story.
It also shows how plugging your car in at, say, 85 per cent, and expecting the claimed maximum charging rate is a fool's errand – all of the cars we charged achieved their best rates when the battery was low, dialling back power as the cells fill up. Above 80 per cent, public charging isn't a good use of time. Advertisement - Article continues below Skip advert Advertisement - Article continues below
So, is it the charger or your car that's causing the shortage of kilowatts? It could be either, but expecting your car to hold the manufacturer's claimed speeds for the duration of a charging session is definitely naive.
As much as we said that whether or not you've pre-conditioned the battery shouldn't matter, getting your car's battery up to the right operating temperature should mean it hits peak speeds more quickly. In some cars you can do this manually at a push of a button, while others integrate this into EV route planning features within the sat-nav.
Most cars have limits on how fast they can charge at higher percentages, to preserve the condition and life of the battery. With this in mind, be sure to plug-in only when the battery gets low, to avoid sitting around for a while.
If you're in a rush, rather than waiting while your car charges at only a few kW as the battery nears 100 per cent, a better idea is to set off and pull over again later to add however much more you need at a higher rate – it will be much quicker.
It's a good idea to plan your journey in advance, because rates can vary so differently between rapid chargers that you might be better off taking a detour to access one with a higher power output, to get you back on the road more quickly.
Our test begs the question: why charge away when you can charge at home? Of course, it's not always possible to do so, but plugging-in before you set off could save you a lot of time, effort and money.
The best way to charge is at home while your car is sitting doing nothing. Although cars prefer to default to 80 per cent charge to preserve battery life, topping up to 100 per cent at home ahead of a longer run will minimise public charging.
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