What size EV charger do I need? 7kW vs 22kW
The 7kW-versus-22kW question sounds like it is about charging speed. Really it is about your electricity supply and for most Irish homes it answers itself.
For almost all Irish homes the answer is 7.4kW. A standard home has a single-phase supply, which caps charging at 7.4kW, and that already adds far more than a typical day's driving range overnight. 22kW charging needs a three-phase supply, which most homes do not have; it is mainly for workplaces and commercial sites. Fitting a 22kW charger to a single-phase home does not make it charge faster the supply still limits it.
It comes down to your supply
Charging power is limited by the electricity supply feeding the house. Single-phase supplies the norm in Irish homes top out at 7.4kW for a charger. Three-phase supplies, common in commercial premises but rare in homes, can support 11kW or 22kW. So the real question is not ‘how fast do I want to charge’ but ‘what supply do I have’.
7.4kW vs 22kW Compared
| Charger | Supply Required | Max Power | Typical Use |
|---|---|---|---|
| 7.4kW | Single-phase (standard home supply) | 7.4kW | Overnight home charging |
| 22kW | Three-phase (rare in homes) | 22kW | Workplace, depot or commercial car park |
Fitting a 22kW charger to a single-phase home does not increase charging speed the supply, not the charger, sets the limit.
Is 7.4kW fast enough?
For overnight home charging, comfortably. At 7.4kW a car gains far more range in a night than most people drive in a day, so it starts each morning full. The extra speed of 22kW mainly matters where cars turn around quickly during the day a workplace or fleet not on a driveway overnight.For more information, see EV charging power sizes
When 22kW Makes Sense
- 1 You have (or are installing) a three-phase supply.
- 2 Vehicles need topping up quickly during the day, not overnight.
- 3 A workplace, depot or commercial car park rather than a home.
The Bottom Line
Unless you have three-phase power and a genuine need for daytime rapid top-ups, 7.4kW is the right home charger. Talk to WEW about the right unit, and see the EV charger buyer's guide for the full decision.
Frequently Asked Questions
-
Can I get 22kW charging at home?
Only if you have a three-phase supply, which most Irish homes do not. On a standard single-phase supply the maximum is 7.4kW, and a 22kW charger will still be limited to that. -
Is 7.4kW enough for an electric car?
Yes, for overnight home charging it is ample. It adds well over a typical day's driving range in a night, so the car is full each morning. -
Will a bigger charger charge my car faster?
Only up to what your supply and your car can accept. On a single-phase home a 22kW charger is still capped at 7.4kW, so it will not charge faster than a 7.4kW unit.
Source it at WEW
WEW (Waveform Electrical Wholesale) is your electrical wholesaler and lighting expert in Meath, supplying trade and homeowners across the region. Call in to the counter or the lighting showroom for stock, advice and everything referenced in this guide.