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.
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