[Jeremy Harris]

Isn't it possible to buy a charger that combines 3 phases into 1 and achieve the 7,4kW speed?

To replace the one in the car, you mean?

There are cars that do this, the Tesla Model 3 for example has three 16 A chargers, and can use two of them in parallel on a single phase supply, or all three separately on a three phase supply. Other cars have chargers that do something similar, varies from model to model.

Bear in mind that the box you have in your home for connecting to the car is not a charger, it's just a power outlet that can either supply single phase or three phase mains power to the charger(s) that are in the car.

 

[meetyg]

Isn't it possible to buy a charger that combines 3 phases into 1 and achieve the 7,4kW speed?

Not that easy to implement. Combining 3 AC phases into one isn't feasible, unlike DC where you can just connect in parallel.
I looked into this issue, as I have 3 phase AC at home, but my Corsa-e accepts only one phase (so charges at a maximum of one phase, meaning 16 Amps, 3.6 kw in my case).

I have come around to a charger which takes two phases and treats them as one higher voltage phase. They use a custom built toroidal transformer to do this.
You can get more info at:

EVTUN | Chargers, wallboxes and range extenders

evtun.com

But since I already had an EVSE installed, replacing it with this 2 phase charger seemed costly to mee, so I gave up on the idea. But it seems like a nice solution.

 

[Orrery]

I have a single phase 16 amp charger and it is fine. I have no need of anything bigger. The only time I notice the limitation is then I arrive home with less than 20% battery and wake up to find it has only charged to 90 odd %, and that is with the charge time limited to 7 hours 'economy 7'.

 

[meetyg]

In the end my "solution" for a bit faster charging was to upgrade my RCBO from 16 amps to 20 amps.
I can control the output of my EVSE from an app, so now I can charge up to 20 amps, giving around 4.2kwh. Still not that fast, but if I keep the battery above 10%, the charge time is more acceptable.

 

[b789pilot]

In the end my "solution" for a bit faster charging was to upgrade my RCBO from 16 amps to 20 amps.
I can control the output of my EVSE from an app, so now I can charge up to 20 amps, giving around 4.2kwh. Still not that fast, but if I keep the battery above 10%, the charge time is more acceptable.

Did you get your car with the 7kW or 11kW charger?