10 Mistakes EV Drivers Make on Long Summer Road Trips

Author: Dmytro Dellert

Source: KW-Kilowat Video Blog

Date: 10.02.25

Introduction

Summer is the perfect time for road trips, but if you’re driving an electric vehicle (EV), high temperatures can pose significant challenges. Extreme heat can cause battery overheating, slow down charging speeds, and reduce overall driving range. On top of that, air conditioning can drain up to 20% of your battery, and overheated charging cables may become less efficient.

I’m Dmytro Dellert, the author of the KW-Kilowat blog, and I’ve experienced multiple long EV journeys in extreme heat. In this article, I’ll cover 10 common mistakes EV drivers make during summer road trips and explain how to avoid them for a smooth, stress-free journey.

📹 Video Experiment: Driving an EV in Extreme Heat

🎥 A real-world test of how high temperatures affect an EV’s performance will be included here.

• How does heat impact an EV’s range?
• How much slower does charging become at 37°C+?
• What settings help maximize efficiency?

1. Underestimating the Impact of Heat on the Battery

When summer temperatures exceed 35°C, EV batteries suffer. They overheat faster, reducing efficiency, and the thermal protection system slows down charging speed. Additionally, high temperatures accelerate cell degradation, especially in EVs that frequently use DC fast charging.

If the battery temperature reaches 45–50°C, the cooling system consumes extra energy, further reducing range. At 55°C, some models—like the Nissan Leaf—may enter a power restriction mode, limiting acceleration and charging speeds.

✅ How to avoid this issue:

• Charge early in the morning or late in the evening when temperatures are lower.
• Use monitoring apps like LeafSpy to track battery temperature.
• If available, enable battery cooling before charging.

2. Overusing the Air Conditioner

Running the air conditioner at full power in extreme heat can drain up to 20% of your battery, especially if the cabin has been sitting in the sun for hours. This issue is particularly critical for EVs without a heat pump, such as older Nissan Leaf and Renault Zoe models.

📌 Real case:

During a road trip in Morocco at 38°C, I noticed that the AC was consuming up to 4 kW, reducing range by 15–20%.

✅ How to save energy:

• Ventilate the cabin before driving to release trapped heat.
• Use the eco mode on your AC system.
• Set the AC to cool only the front seats instead of the entire cabin.
• If your EV supports preconditioning, cool the cabin while plugged in before starting your trip.

3. Charging an EV in Direct Sunlight

Charging an EV under the scorching sun can cause the battery temperature to exceed 50°C, significantly slowing down the charging process.

📌 Real case:

In Namibia, while charging my Hyundai Kona Electric at 42°C, the charging power on a 50-kW station dropped to just 30 kW instead of the usual 75 kW due to battery overheating.

✅ How to avoid this issue:

• Look for shaded or covered charging stations.
• Charge your EV at night or early morning when temperatures are lower.
• If the battery overheats, allow it to cool down before charging.

4. Driving Too Fast on the Highway

Higher speeds significantly reduce EV range, especially in hot weather. For example:

• At 90 km/h, a Nissan Leaf 40 kWh can travel about 250 km.
• At 120 km/h, that range drops to 170–180 km.

Hot weather increases tire rolling resistance and aerodynamic drag, which further increases energy consumption.

✅ Best driving strategies:

• Maintain speeds between 90–100 km/h for better efficiency.
• Use cruise control to optimize energy use.
• Enable regenerative braking to recover energy when slowing down.

5. Ignoring Tire Pressure

In hot weather, tire pressure fluctuates. Underinflated tires increase rolling resistance, which raises energy consumption and reduces range.

✅ How to avoid this issue:

• Check tire pressure before every trip and adjust as needed.
• Inflate tires 0.2–0.3 bar above the recommended level to compensate for heat.
• Use summer tires instead of all-season ones to reduce resistance.

6. Overheated Charging Cables

🔌 What happens?

When temperatures exceed 35°C, charging cables—especially at DC fast charging stations—can overheat. This can lead to:

• Power loss – charging slows down.
• Automatic shutdown – if the cable gets too hot, charging may stop.
• Connector wear – high temperatures can damage the charging plug.

📌 Real case:

During one of my summer trips in a Hyundai Kona Electric, I encountered an issue where a 50-kW DC fast charger at 42°C dropped its power output to just 15 kW due to cable overheating.

✅ How to avoid this issue:

• If the cable is hot, wipe it with a damp cloth before plugging it in (a trick used at Tesla Superchargers).
• If your EV allows it, reduce the charging power (e.g., from 50 kW to 30 kW).
• Use charging stations with liquid-cooled cables (such as Ionity or Tesla V3 Superchargers).

7. Running the Battery to 0% Before Charging

Fully depleting the battery before charging reduces cooling efficiency, making the charging process even slower in hot conditions.

✅ How to do it right:

• Start charging when battery level drops to 15–20%.
• Never leave an EV with a low battery parked in direct sunlight.

8. Ignoring Battery Cooling Systems

🛠️ Why is this important?

Most modern EVs (Tesla, Hyundai, BMW i3) use liquid cooling for their batteries, but many drivers neglect maintenance. If coolant evaporates or becomes contaminated, the cooling system loses efficiency, and the battery overheats faster.

📌 Which EVs require cooling system checks?

• Liquid-cooled EVs: Tesla Model 3/Y, Hyundai Kona, Kia EV6, BMW i3.
• Air-cooled EVs (require ventilation): Nissan Leaf, Renault Zoe.

📌 Real case:

During a summer trip in a Nissan Leaf 30 kWh, the battery temperature exceeded 50°C due to the lack of a liquid cooling system.

✅ How to prevent overheating?

• Check coolant levels before summer trips (if applicable).
• For air-cooled EVs, avoid charging in enclosed garages with poor ventilation.
• Charge at night when temperatures are lower.

9. Misusing Solar Panels on EVs

☀️ How can solar panels be beneficial?

Some EVs (Hyundai Ioniq 5, Toyota Prius Prime) come equipped with solar panels that can help charge the battery.

📌 What do they actually provide?

• In hot climates, they can add up to 10 km of extra range per day.
• They help charge the 12V auxiliary battery, preventing it from draining.
• They reduce air conditioning power consumption by powering auxiliary systems.

✅ How to use them correctly?

• If your EV has solar panels, park in sunlight, but ensure the battery doesn’t overheat.
• Enable solar charging mode if available (e.g., Hyundai Ioniq 5).
• If your EV doesn’t have solar panels, park in the shade to avoid cabin overheating.

📌 Myth:

Some drivers believe solar panels can fully recharge an EV battery—this is not true. They provide small energy boosts but are not a replacement for regular charging.

10. Assuming Charging Stations Will Be Available

In summer, high demand for charging can lead to long wait times at popular tourist destinations.

✅ How to avoid this issue:

• Check station availability via PlugShare or ABRP before heading out.
• Plan multiple charging stops as backups.

Conclusion

Extreme summer heat can reduce your EV’s range by 20–30% if you’re not prepared. To avoid overheating, slow charging, and excessive energy consumption, plan your route carefully, monitor battery temperature, and optimize your driving habits.

🚗 Now you know how to prepare your EV for hot weather!