Right, time to see how that slow, fast and rapid charging works to get the car charged in daily use. For most electric car buyers, the cheapest and easiest way to charge will be at home. But if you’re on longer trips, have no opportunity to charge at home or if those thieving power pixies have spirited away your very last amp and volt, you’ll need to avail yourself of a fast charger.
Here’s where kilowatts come into play again. Your regular wall socket at home can usually deliver about 2.3kW, so you’ll add (wait for it) 2.3kWh of range to your battery every hour. This is slow or level 1 charging. This also doesn’t sound great – especially if your battery has a capacity of 100kWh, and you’re wondering what 100 divided by 2.3 is so you know when you’ll have a full charge. It’s about 43 hours and 29 minutes, in case you were curious.
Fast (level 2) home chargers can deliver a much healthier 3.6 or 7kW, which reduces the empty to 100 per cent charge time to 27 hours, 47 minutes, and 14 hours, 17 minutes respectively. You can also find fast chargers in car parks or at the side of residential streets where there are no driveways.
But you don’t need a full battery any more than you need a full tank of petrol to drive around. If you charge overnight at home on a 7kW fast charge point, you can go from an empty 100kWh battery to more than half full in eight hours, all while buying useless, off-brand crap from Amazon and getting a bit of sleep in front of Netflix while it worriedly asks you if you’re still there. Even chucking it on to charge for an hour at home gives you another 20 miles of range, exactly enough for a trip to work and back for the average UK commuter.
But, like we said, home charging isn’t always available, or situationally appropriate. While it does make sense to charge at home, it makes less sense to buy a series of houses at 120-mile intervals along the M1 so you can always charge at home. And here’s where rapid chargers come in.
Out and about, rapid DC chargers are much more potent than anything AC or domestic. Tesla Superchargers can reach 250kW, or enough to fill a 100kWh battery in 24 minutes – theoretically. Porsche has plans to go as far as 350kW soon, which will (very theoretically) brim an empty 100kWh battery in 17 minutes. We’ll need to come up with a new phrase for splash’n’dash… zap’n’zip?
But, because this is the real world, it’s never as simple as that. You’ll never be truly empty, and battery chargers have to slow down the rate of power transmission as the battery reaches full charge, otherwise there’s a risk of damaging the battery. But, for instance, if you’re at 7.5 per cent charge of a 100kWh battery – the electric version of fumes – and then top up at a 250kW charger for just the 15 minutes it takes to get a sandwich and a coffee, you’ve added 62.5kWh, and gone up to 70 per cent charge, netting yourself another 250-odd miles of range.
This scenario is an ideal one, but it’s one that’s very likely to become more common as faster chargers spring up. We’ve personally used the 120kW Tesla Supercharger on a Model 3 (out at Membury, if you were curious) and spent somewhere between 30 and 45 minutes sitting down with a sandwich, a coffee and a laptop to type up articles (just like this one) and walked out to find that our Model 3 was basically fully charged. It really does happen faster than you think.
So, if that’s the ideal (and idealised) scenario, what happens if you didn’t want (or didn’t get) a Tesla? Well, then we have to start talking about CHAdeMO and CCS.
As of 2020, the maximum charger kW you’ll ever encounter is 250kW for Tesla, 350kW for CCS and 400kW for CHAdeMO. Now, that sounds, and is, incredible. But there are a few issues for the time being – a) they’re still being rolled out, so they’re rare, b) a lot of EVs won’t accept a charge that fast, so you’ll more likely be charging at 50 to 100kW regardless of where you hook up, and c) we’re going to need some pretty substantial work on the power grid before every man and his electric car are dragging hundreds of kilowatts at once. But we figured out space travel, supersonic flight and deep-sea submarines, didn’t we?