How future proof is slow EV charging?

“How future proof is this” is something councils often ask us about slow charging on a lamppost. Will charging slower than 7kW be enough for the future or will it be obsolete?

At char.gy , we believe in sharing our field-based insights about the reality of public charging. So here’s an objective way to work out the answer.

We need to look at how people charge today and then work out how much that will change in future.?

Today

How much power can we get out of a lamppost? We install lamppost chargers with power outputs ranging from 3 to 5.3kW. The reason is some DNOs are more conservative than others and some lampposts have more power capacity than others. We always aim to offer the maximum power output possible per lamppost.

Today 75% of charging events on our network are 35kWh or less. What does that mean in charging behaviours??That's up to:

• 7 hours charging on a standard 5.3kW lamppost charger
• 10 hours charging on a 3.6kW charger where the local network requires the charge point to be downrated.?

An average charge is just over 22kWh. That’s between 4 and 6 hours of active charging, depending on the charge point’s power rating.

Drivers spend an average of 8.5 hours plugged in.?

35kWh is 120 miles of driving in an average EV with 3.5miles/kWh efficiency. That’s more than the weekly average mileage of private drivers.

What about the cars? How much is 35kWh as a proportion of the car’s battery?

• 50% of an efficient long-range EV, like a Tesla Model 3 / Y or Ionic 5 / 6
• 70% of a standard range EV like an MG4, ID3 or Vauxhall Corsa-e
• 100% of a city EV like a Fiat 500, Honda e or Mini.

Critical thinking

The critical factors are whether drivers need more kWhs per charge or have less time to charge at home.

Here are 5 reasons why that won’t be the case.?

Tomorrow

1. Vehicle efficiency

EV’s are likely to get more efficient, i.e. deliver more miles per kWh. Why? Because more energy dense batteries means EVs will need smaller battery packs. The weight saving will help them go further on those kWhs. And like heat pumps have replaced resistive heaters, there are probably other untapped sources of efficiency waiting to be unlocked.?This could include solar panels on the roof, like on the new Fisker Ocean unveiled at FullyCharged.SHOW & Everything Electric .

2.??Average mileage

We don’t drive as far as we used to. Annual average mileage fell from 9,200 in 2002 to 5,300 in 2021. Maybe mileage will bounce back post pandemic? Well, even before the pandemic, annual average mileage had fallen to 7000 miles. With active travel options becoming easier and more inviting (cheaper electric bikes, more cycle lanes), we're unlikely to go back to the high mileage years.

3.?Car prices

Average battery pack sizes will probably shrink. EVs won’t be premium forever. To enable car makers to hit lower price points and sell EVs to budget-conscious buyers, the most expensive component, the battery pack, will be smaller.

4.??Charging prices

Public charging prices are significantly lower on AC chargers than DC chargers. Zapmap ’s Price Index puts the average difference at 24p/kWh (April 2023). With the current average AC price of 51p/kWh and the DC prive at 75p/kWh, it costs about 50% more to charge on a rapid charge point than a slow/fast charge point.

Amongst the AC networks, the lamppost networks offer the lowest prices and were the first to offer significantly lower prices for overnight charging. Overnight charging on the char.gy network costs just 29p/kWh (May 2023). Since introducing that rate in December, we've seen a huge shift in our customers' charging patterns to take advantage of our cheapest rate.

5.??Habits endure, easy wins

In future, we’ll still have plenty of time to charge at home.

• Our sleeping habits won’t change. We’ll still need (or least desire) 8 hours sleep. This is the easiest time to recharge.
• Our cars will still spend most of their time parked. The RAC puts that at 96% of a car's life with 73% of that time parked outside our homes.?This is the easiest place to recharge.
• We’ll still favour convenience. A 1-2 minute walk from your front door to your nearest lamppost is far more appealing than a 5-15 minute walk to a council car park or bank of kerb-side charge points. ?

But wait! Whaddabout hybrids?

Today roughly half of all EVs on the road are plug in hybrids. (Self-charging hybrids aren’t EVs. They’re just more efficient ICE cars.)

Plug in hybrids have small battery packs - typically 12kWh or less. As the market moves to a higher proportion of BEVs where most batteries are in the 40-70kWh range, won’t that change things??

No. The five factors described above still apply.

We expect the average charging event to increase closer to 30kWh as the proportion of hybrids falls, but the other factors means most charging events should stay around or under 35kWh.

So there you have it.

Lamppost chargers may sound slow, but they'll be a steady part of the charging mix for people who can't charge on their private driveway.