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Sep 24, 2023

How fast can I charge my electric car? 

As explained in my recent article on charging – the key change when moving from ICE (Internal Combustion Engine) to EV is the way you think about ‘refilling’. Charging an EV is now a destination task, not a within-trip one.

Having been driving EV for many years, if I drive an ICE vehicle I REALLY notice how inconvenient refuelling one is. Instead of plugging in when I arrive and walking away to do my own thing, I must allow time within my trip to detour to the fuel station, stop, get out and stand there holding the pump nozzle. After all that is done, I still have to go and pay before I can finally proceed out into the traffic and back to my intended route.

Instead, after I plug in, I just wander off to ‘do my thing’ with a rough plan of my time based around ‘what amount of charge will I have when I return?’

To help the new generation of EV owners coming through, I thought I would pass on the concept of ‘km charged per hour’ as a metric to use when you choose your charging means (and/or to help choose the EV that suits you best).

All new EVs come with a portable charger to plug into a standard 10A power point (I call these trickle chargers). With one of these, you get around 15 kilometres charged per hour. (I’ll abbreviate this to ‘km ch/hr’).

Trickle charging is great for smaller overnight recharges, or on the road to get you out of trouble – but it's really only the equivalent of the Roadside Assist van arriving to give you a small jerrican of fuel – enough to get to the nearest petrol station. (As an aside: don't use the trickle charger that comes with the car as your primary charger … or it will likely be left behind in the garage power point the one time you needed it as that ‘jerrican’!)

For a trickle charger, a half hour on a power point will give you 7-ish km of range. With any luck that will get you home, or at least to a faster charger. (With a whole lot less down-time than waiting for the roadside assist van to turn up with that jerrican of fuel).

The next step up is a 15A outlet (as found in caravan parks … or you can install one for EV charging use at home – starting from around $500). One of these will give approximately 25 km ch/hr. If you have a portable charger that switches between charging rates – then you can up the rate to the 15A setting and replenish 250km in 10 hours or around 375 in 15 hours. That’ll usually provide more than enough to get moving again on a weekend away – and will even cover many EVs for overnight home charging.

Moving on up from there, a dedicated home charger on 32A will give you around 50 km ch/hr (32A is the highest rate the typical single phase household can supply). For most EVs, this will give you a full charge within the usual off-peak rate period. (50 km ch/hr x 8 hrs = 400 km).

That is where AC charging for older (and many current) EVs maxes out. To go higher requires a DC fast charger. The same calculations apply, just you get much faster km ch/hr rates! (See table 1).

However, what I call the ‘EV charging Speed Advertising Battle’ is now hotting up, so more and more EVs are being advertised with ever higher AC (and DC) charging speeds.

The leader in all things EV, Tesla, has long done 11kW as their standard AC charge rate. However, virtually all the high-end marques (like BMW, Porsche, Jaguar, Audi and Mercedes) have caught up and now do 11kW AC charging as standard. Plus, to up the ante, several also offer 22kW AC as an option. Renault, by the way, is an outlier in this regard, as the Zoe sold here was always 22kW AC plus the coming e-tech Megane has 22kW as standard.

In recent times the upper-middle price category has started to follow suit with 11kW AC charging as standard. (These include the likes of the Hyundai Ioniq 5, Polestar 2, Volvo C40 and XC 40 and Kia EV6). Now even the cheapest EV on the market (the MG ZS EV) is offering 11kW AC as an option – so it is likely the others will soon follow to keep up in the advertising battle to offer the fastest AC charging speed.

So where will this particular advertising battle end? For AC, 22kW AC charging is, for a variety of reasons, the practical upper limit. For DC, that limit is probably going to be 350kW for passenger vehicles. (FYI: for trucks, that limit is looking to be 1MW DC – but that battle has yet to start).

So what does all this mean? To simplify all the above, I like to use the following table. You can either print it out, or (like me) use it for mental arithmetic as you wander off to lunch, or perhaps to bed in my personal 20 second recharge time. (By which I mean 10 seconds to plug in, and another 10 seconds to unplug once I return to my car).

Bryce Gaton is an expert on electric vehicles and contributor for The Driven and Renew Economy. He has been working in the EV sector since 2008 and is currently working as EV electrical safety trainer/supervisor for the University of Melbourne. He also provides support for the EV Transition to business, government and the public through his EV Transition consultancy EVchoice.

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