Tools
Charger sizing tool: what size EV charger do I need?
Answer a few questions about your car, your supply and your parking time to see which charger power makes sense.
Our suggestion
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- Energy needed per day
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- Time to recharge daily use
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How we size
How the sizing tool works
The charging speed you actually get is limited by the lowest of three things: the charger's rated power, your car's onboard AC charger and your electrical supply. A single-phase supply typically supports up to about 7 kW; a three-phase supply can support 11 or 22 kW if the car can accept it. The tool compares these limits, then checks the energy you need to replace each day against the hours you are usually parked. Results are a guide only. Your actual supply capacity, DB board and cable run must be confirmed during a site assessment.
Three limits that set your charging speed
Your car, your supply and your charger each have a maximum. Charging runs at whichever is lowest. Many EVs and plug-in hybrids sold in South Africa accept around 7 kW or 11 kW on AC, and most homes have a single-phase supply. That is why a 7 kW wallbox suits the majority of households.
When a bigger charger makes sense
Three-phase sites with cars that accept 11 kW or 22 kW, shared bays where several cars charge in a day, and workplaces with short dwell times can justify a higher-power charger. In complexes and offices, load management lets several chargers share the available supply. For a fuller explanation, read our guide to single-phase vs three-phase EV charging.
Next steps
Compare home AC chargers and commercial AC chargers, or book a site assessment so we can confirm your supply before you buy.
Is a 22 kW charger worth it on a single-phase supply?
No. A single-phase supply cannot deliver 22 kW, so the charger would run at a much lower power. A 7 kW charger is the sensible choice for most single-phase homes.
My car only accepts 7 kW AC. Should I still buy a 22 kW charger?
Only if you expect a future car with a larger onboard charger and you have a three-phase supply. Otherwise a 7 kW or 11 kW unit will charge your car just as quickly.
How do I know if I have a three-phase supply?
Look at your main breaker in the DB board: a three-pole main switch usually means three-phase. Your electricity bill or our site assessment will confirm it.
Talk to StrataCharge
Get a clear, itemised quote
Tell us about your site and the vehicles you need to charge. We reply to messages within one business day.