Why "Rapid Charge Paradox"?
AC charging is often the most convenient option
The Origin of a Name
When launching a consultancy focused on Electric Vehicle (EV) (Charging) strategy, I needed a distinctive name (not least for Google) and wanted one that would instantly convey a degree of insight about EV charging behavior - and how it differs from refueling an internal combustion engine vehicle. So I picked the name of a paradox I had previously coined.
What Is "McKemey's Rapid Charge Paradox"?
McKemey's Rapid Charge Paradox states: "The faster the charger, the longer you spend waiting."
This seemingly contradictory principle captures an essential truth about real driver behavior and convenience.
Home/Work Charging vs. Rapid Charging
The paradox began with understanding the fundamental difference between two charging approaches:
Home/Work Charging (usually 7kW AC)
Adds ~25-30 miles of range per hour
Happens while you're sleeping, working, or otherwise engaged
Material waiting time: Zero
Rapid Charging (DC Fast Charging)
Adds range significantly faster (see below)
Requires a dedicated trip to a charging station
Material waiting time: The trip to and from the charging station, and the whole charging time
The original level of the paradox emerges here: while technically slower in charging speed, home/work (and often destination) charging results in less material waiting time because the charging happens in the background of your life. You're not actively waiting for your car to charge, you're living your life while the car charges.
This insight leads to my own recommendation for EV drivers: "Charge where you park, park where you can charge." By integrating charging into normal activities whenever possible, you minimise your material waiting time regardless of the actual charging speed, maximising your convenience.
The Evolving Paradox: Rapid vs. Ultra-Rapid Charging
As DC rapid charging technology has advanced, a second level of the paradox has emerged within the rapid charging experience itself:
Rapid DC Charging (~100kW)
Adds ~40-60 miles of range per 15 minutes
Typical session lasts 30-45 minutes
Creates an often useful waiting period - enough time to grab lunch or coffee
Perceived waiting quality: Moderate, but relaxed/productive
Ultra-Rapid DC Charging (~350kW)
Adds ~100-200+ miles of range per 15 minutes
Typical session lasts 10-15 minutes
Often too short to comfortably engage in other activities
Requires vigilant monitoring due to higher costs and potential overstay fees
Perceived waiting quality: Short but intensely felt
This evolution of the paradox reveals that within rapid charging itself, the fastest option doesn't always provide the best user experience. The ultra-rapid 350kW session creates what might be called "stranded time" - too short to meaningfully engage in another activity, but long enough to feel the wait acutely.
Why This Matters
Understanding the Rapid Charge Paradox helps both EV drivers and charging infrastructure providers make better decisions:
For EV Drivers
New EV owners are often surprised by how rarely they need rapid charging in daily use
The most convenient charging is often the one that fits naturally into your existing routine
Different charging speeds are optimal for different scenarios and contexts
For Charging Providers
Charging location selection should consider dwell time at different types of destinations
User experience design needs to account for the psychological aspects of waiting
Amenities and facilities should be tailored to the typical charging duration
The Critical Role of DC Rapid Charging
It's important to emphasize that the Rapid Charge Paradox is not an argument against DC rapid charging. There is no such argument. Rapid charging infrastructure is absolutely essential to the EV charging ecosystem for several reasons:
Enabling long-distance travel - Without DC rapid charging, EVs would be materially limited to half their range - they need to get there and back
Supporting commercial fleets - Highly utilised taxis, delivery vehicles, and other such vehicles may need quick turnaround times
Providing flexibility - Everyone gets caught short now and then - e.g. forgot to charge home/work, driven more than expected - DC charging solves this
Potentially providing regular charging for those without home charging - Some residents without regular access to home/work charging may choose to regularly use DC charging, though there may be more affordable and convenient alternative
Conclusion
The name "Rapid Charge Paradox" is both unique for the firm, whilst capturing both a fundamental insight about EV charging behavior and a philosophy about how we should approach charging infrastructure design. As EVs continue to replace internal combustion engines, understanding this paradox becomes increasingly important for driving adoption and improving user experience.
Faster isn’t necessarily better, the right infrastructure means finding the optimal intersection of technology, economics, and human factors. A balanced charging ecosystem needs the right charging options in the right places.
