Your new electric car seemed to promise rapid charging speeds. But you’ve noticed it’s not quite living up to expectations. You’re not alone.
Many EV owners find their charging speeds vary significantly from what they expected. While manufacturers quote impressive charging times, the reality often differs due to various factors affecting how quickly your car charges. Just as your phone doesn’t always charge at the same speed, your electric car’s charging rate can vary for many different reasons. From the type of charger you’re using to the weather outside, numerous factors influence how quickly your battery fills.
These variations in charging speed aren’t necessarily faults with your car or charger. They’re normal characteristics of EV battery technology, built in to protect your battery and ensure safe, reliable charging. Slower charging can feel frustrating, but there’s usually a simple explanation… and often a solution.
While some factors lie beyond your control, understanding what affects your charging speed helps you make better decisions about when and where to charge. This blog explores the five main reasons your EV might charge slower than you’d expect.
Charging capacity vs charger output
Your car and your EV charging point must work together, but they don’t always match perfectly. Every electric car has a maximum charging capacity, measured in kilowatts (kW). This determines the fastest rate at which it can accept power. Meanwhile, charging points have their own maximum power output. Your charging speed will always be limited by whichever is lower.
For example, if your EV can accept 11kW but you’re using a 7kW home charger, you’ll only charge at 7kW. Similarly, if your EV accepts a maximum of 7kW but you’re using a 22kW charger, you’ll still only charge at 7kW. Understanding these limitations helps set realistic expectations for charging times.
Using a 3-pin socket instead of a proper EV charging point
A standard three-pin socket might seem like a convenient charging solution. But it significantly impacts your charging speed. These sockets, designed for household appliances, can only deliver a maximum of 2.3kW. That’s less than a third of what a proper home EV charging point provides.
This low power output means painfully slow charging times. While a dedicated 7kW charging point can add around 25 miles of range per hour, a three-pin socket manages just 8 miles. For a typical electric car with a 60kWh battery, charging from empty could take more than 24 hours through a standard socket.
Your granny cable (the special charging cable that connects to a three-pin socket) includes safety features that deliberately limit the power flow. These protect your home’s wiring but mean even slower charging. So, save three-pin charging for emergencies and consider installing a dedicated home EV charging point for day-to-day use.
Battery temperature
Your EV’s battery performs best within a specific temperature range, typically between 20°C to 40°C. When temperatures fall significantly below or rise above this sweet spot, charging speeds can drop dramatically.
In winter, cold batteries resist charging, forcing slower rates to prevent damage. Your car’s battery management system might need to warm the battery before accepting full charging power, using energy that could otherwise go into charging. This explains why winter charging often takes longer than summer charging.
Hot weather brings its own challenges. High temperatures can cause batteries to heat up during charging, prompting the car’s safety systems to reduce charging speed to prevent overheating. Your car might also divert some power to its cooling systems, extending the overall charging time.
Charge state
Your battery’s current charge level influences how quickly it can accept more power. EV batteries charge fastest when they’re between 20% and 80% full. Above 80%, charging speeds drop considerably as the battery management system protects against overcharging. This explains why rapid chargers often quote times to 80% rather than 100%.
This characteristic affects daily your charging patterns. For longer battery life and faster charging, many manufacturers recommend keeping your battery between 20% and 80% charge for everyday use, charging to 100% only for occasional long journeys.
Power sharing
When several EVs charge simultaneously from the same power source, they must share the available power. This affects both public charging stations and home setups with multiple charging points.
At public charging locations, two chargers might share one power supply. If you’re the second car to plug in, you might find your charging speed halved. Some charging networks show this information in their apps, helping you choose the fastest available charger.
For home installations with multiple EVs, your electrician can install load-balancing systems that manage power distribution between charging points. This prevents overloading your supply, but might mean slower charging when multiple cars charge together.
What can you do about it?
Understanding these factors helps you plan your charging more effectively, ensuring you get the fastest possible charging speeds from your electric car. While you can’t control all the variables that affect charging speed, you can take steps to optimise your charging routine. Installing a dedicated home EV charging point will make the biggest difference to your charging experience. A proper charging point delivers up to three times the power of a standard socket, transforming your charging speeds and giving you more control over when and how you charge.
For daily charging, try to keep your battery level between 20% and 80%. This sweet spot allows for the fastest charging speeds and helps preserve your battery’s long-term health. Only charge to 100% when you’re planning a longer journey that needs the extra range. If you’re using public charging points, timing matters. Choose off-peak hours when stations are less likely to be busy, reducing the chance of sharing power with other vehicles. Many charging networks offer apps showing real-time availability. Use them to find the quietest locations.
Weather plays a crucial role, too. When possible, park in covered areas during extreme weather to keep your battery at optimal temperature. If you’re charging in very hot or cold conditions, allow extra time, as your car’s battery management system might need to heat or cool the battery before accepting full charging power. These simple adjustments to your charging routine can make a significant difference to your charging speeds.
How can Electrical Innovations (Derby) Ltd help?
Need advice about your EV charging setup? Our qualified team can help you understand your options and find the best charging solution for your needs. We have vast expertise in installing market-leading, OZEV-approved residential EV charging points from manufacturers including Hypervolt, MyEnergi and Sync EV. We’ll ensure your home charging point is safe, convenient and efficient to help you get the most out of your electric vehicle.
