The importance of a faster internal charger

LIDL offering free charging with solar panels

Now that electric car batteries with a capacity between 40 kWh and 60 kWh are getting more mainstream we frequently think about 100-150 kW DC fast chargers and tend to forget how useful faster internal chargers are. Having the capability to charge at 150 kW would be great in few occasions like emergencies or that long trip on vacations. But the internal charger is the one we tend to use much more frequently. To me it’s obvious, if I had to choose I would choose the electric car with the faster internal charger, how fast it charges on DC fast chargers is secondary to me.


A faster internal charger not only saves you time and makes your life easier but it can also save you some money.

Let’s see some examples of this kind of situations:

  • you can put more kWh in your battery when you have limited time to charge for free. For example when you are at work or shopping.
  • you can more frequently avoid the DC fast chargers that are more rare, expensive to use and put more stress on the battery  – especially if the battery doesn’t have active cooling.
  • you can easily fully charge your battery at night during off-peak hours when electricity rates are cheaper.


I’m not a proponent of charging only at night, because I think that the electric car should always be ready to go. Every time that it’s stopped it’s a good opportunity to charge, regardless the time of the day. The real reason why I think that the internal charger can save you some money is because you can put more kWh in you battery for free while you’re shopping.

Some European retailers such as LIDL, E.Leclerc and Auchan allow free charging at 22 kW EVSEs. This is a trend that’ll see becoming mainstream, especially since these retailers are also investing in solar panels. Offering customers free charge is a great marketing strategy, as it attracts affluent buyers (with high purchasing ability) and makes the brand more green to their eyes.

Of course that some retailers will have some expensive DC fast chargers, but the majority will be simple EVSEs – that supply AC to the internal charger -, since they are cheaper to buy, install and servicing. With that free charging we want to charge as much as possible while we are shopping. If you spend half an hour at shopping and charge at a 22 kW EVSE you get 11 kWh if your internal charger is also 22 kW (three-phase 32 A), but if it’s only 3,6 kW (single-phase 16 A) you get 1,8 kWh in half an hour.


In the long run I can only see paid charging working with DC fast chargers, not many persons will be willing to pay for the EVSE’s access since there will be many free at retailers. What can work is paid parking with free access to EVSEs, also in this case you want to charge as fast as possible.


For example let’s assume you live in Germany and pay 0,295 € per kWh at home, if you charge everyday half an hour at LIDL you get 9,2 kWh more if your internal charger is 22 kW instead of 3,6 kW. This free 9,2 kWh charge corresponds to 10,469 € saved. In a year with 365 days you can save as much as 3.821 € if you charge for free everyday…

This is why I think that every electric car should have a standard 7,4 kW internal charger and an optional 22 kW charger.

For example the popular Brusa NLG664 22 kW charger weighs 12 kg and have an efficiency of 94 %, while the 3,6 kW Brusa NLG513 Air charger weighs 6,3 kg and have an efficiency of 93 %. Only 5,7 kg of difference.


How much would you be willing to pay more to have a 22 kW charger?

Which more retailers do you know that offer free charge? In Portugal, IKEA gives free access to 7,4 kW EVSEs, not as good as 22 kW but not bad.



More info:

Pedro Lima

My interest in electric transportation is mostly political. I’m tired of coups and wars for oil. My expectation is that the adoption of electric transportation will be a factor for peace and democracy all over the world.

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5 years ago

Sorry, but your strongly opinionated post is also very incorrect.
The internal chargers are only for overnight charging. Currently they are used at charging stations because there are not many DC chargers and because there are a lot of cars without DC charging.
Once most EVs get batteries above 50 kWh, there will be no need to keep your car topped-up at all times and the internal chargers will also not be able to keep up to the large battery.
Charging a 60 kWh battery with a 22kW AC charger will take 2-3 hours. This is way to slow for charging stations but also needlessly fast for other scenarios like destination charging (restaurants, hotels, malls) or overnight charging. I personally would prefer four 6kW chargers at the local mall/restaurant instead of a single 22Kw charger that will be always taken by a car with a fill battery that was left there hours ago.
large AC chargers are an outdated concept and we should stop wasting money and time on it.

5 years ago

Buying a 22 kWh internal charger only because you could use it at LIDL and save a couple of bucks is quite idiotic. Once 20-30% of the cars on the road are electric no mall/restaurant/store will install free chargers that are more than 3-4 kW. There is no LIDL on the planet with a grid connection that could handle 20 X 22kWh. And having only a single 22kWh charger when 20-30% of your customers have EVs is pointless.

5 years ago
Reply to  tosho

Lidl was obviously just an example, and the point expressly made was that it’ll be in many places. So pretending to argue against using it “only at Lidl” is what’s “quite idiotic”.

22 kW chargers cost almost exactly the same as 3,6 kW ones. So even if you used only 3,6 kW most of the time it’d be well worth it.

Renault gets it. And the ZOE proves it isn’t expensive.

5 years ago
Reply to  Terawatt

I guess I didn’t explain it well. Once we have millions of EVs on the road no-one will install 22kW destination chargers. Most stores/malls/hotels will have to install multiple chargers to keep customers happy. There will be no point to have a single 22kW when you have hundreds of customers that want to charge their cars every day. But installing 10-20 or more 22kW chargers is very difficult. The chargers themselves do not cost much money but both the strong connection to the grid and the monthly electricity bill will be to costly for a “free extra” service.
And stop giving the ZOE as an example – it has a large AC charger only because it has a large battery and no DC charging.
Anyway, most manufacturers have started putting smaller AC chargers in their cars. This won’t change in the future because there are no real reasons for large AC chargers anymore. Even the next ZOE will probably have DC charging and a smell AC charger. So this discussion is pointless.

5 years ago

I completely agree. Not sure how applicable this is in the US or Asia, but for Europe where the grids are universally 400V 3-phase this is almost as simple as connecting to the grid (nearly all the electronics being in the car).

Only Renault is currently supplying an onboard charger appropriate for Europe! If customers paid more attention to this aspect Nissan and all the others would follow suit.

With wireless charging the onboard charger becomes even more important. There’s no such thing as wireless DC, so the onboard charger will define the upper limit for wireless charging speed. I’d love to be able to charge wirelessly at a restaurant or the mall – places where I may spend anything from twenty minutes to a few hours.

Because of wireless this also matters for destination charging. 3,6 kW isn’t enough for overnight charging from a low SoC to 100% when you’ve got 60 kWh! But with 22 kW (tapering off at the end) it can be done in 3-4 hours.

Autonomous cars and wireless charging are two complimentary events that will happen sooner rather than later. The car will be able to drive itself, but it won’t be able to plug itself into a fast charger. You drive to the door of the restaurant, and the car drives itself to the wireless charger nearby, coming back to pick you up when you summon it…

Renault ZOE proves a proper onboard charger isn’t expensive. Before, it could even go all the way to 43 kW – something that isn’t practically very valuable however because type 2 EVSEs hardly ever support more than 22 kW.

5 years ago

I can agree that a 22KW charger will give you more freedom of choise, but it will definitly not save you money. Peak load is a challenge for the power companies. The investments needed to make the power grid more robust will have to be payd for by the custommers. In Norway most of the power companies plan to use peak load as a criteria for how much the custommers are going to pay for electric power in the future. That means that 22KW home charge will be a lot more expensive than using 3.6KW.

Most people will only need to charge 5-10 KWh a day to cover the daily driving distance. That means that 4-5 hours at 2,2kW will be sufficient. So why do they need 22kW AC charging? For longer road trips you will prefer fast DC charging anyway.

3 years ago

Brusa NLG664 is almost $7000 dollars!