How to stay safe when using electric vehicles in extreme heat, rain

Various parts of Vietnam are reporting extreme weather conditions, with prolonged heat and showers alternating throughout the day. Abrupt changes in weather, temperature and humidity can affect EVs.

Operating electric motorbikes and cars safely has become a major concern since their performance is directly affected by environmental factors.

A person rides an electric motorbike in downtown HCMC. Photo by VnExpress/Thanh Tung

Heat waves have pushed ambient temperatures to 35-40 degrees Celsius. In such conditions, lithium-ion batteries, commonly used in both electric motorbikes and cars, are prone to overheating if left under the sun for too long or charged immediately after long trips.

Research shows that the optimal operating temperature range for lithium-ion batteries is 20-30 degrees Celsius. Higher temperatures can shorten battery life, cause faster degradation and, in some cases, reduce vehicle performance.

Batteries and control units in electric motorbikes are typically placed under the floor. Sudden downpours can short-circuit these components when traveling through water, especially if the waterproof seals have deteriorated with age. Charging ports and adapters left outdoors can also short-circuit in the rain.

Most modern electric cars are water resistant by design, but this protection can degrade prematurely if the vehicle is frequently driven through floodwaters or left outdoors for long periods of time.

To ensure safety during extreme weather, owners should tweak certain usage habits. For instance, they should avoid parking under direct sunlight for too long, especially at midday, and instead find shaded areas, covered parking or indoor parking wherever possible. For electric cars parked outdoors, use heat-reflective covers to reduce temperature buildup.

A charging electric vehicle in a shopping mall basement in Hanoi. Photo by VnExpress/Cuong Manh

After a long trip in hot weather, avoid charging the battery immediately. Charging while the battery is hot can reduce its lifespan over time. It is best to let the vehicle rest for 15-30 minutes in a well-ventilated place before plugging in.

Many electric cars are now equipped with battery cooling systems, which activate during charging or when battery temperatures rise to protect battery life. These are still rare in electric motorbikes.

In rainy conditions, owners should avoid flooded areas when possible. After riding in the rain, dry the charging port and plug area.

When charging electric motorbikes at home with a portable adapter, place the adapter in dry, well-ventilated locations. Keep it flat and its vents uncovered to prevent damage.

Plastic cover for EV charging gun. Photo by courtesy of Amazon

Electric car owners can buy plastic covers for their charging guns to use in the rain. But these products may cause overheating, reduce charging efficiency, trap moisture, speed up pin oxidation, and let rainwater collect if punctured.

Most charging guns and ports in electric vehicles already meet IP55 or higher water resistance standards, the international certification for ingress protection. They also have multiple safety layers to prevent short circuits.

Besides, EV owners should carry out regular maintenance. Batteries, controllers, electrical connectors, and waterproof seals are vulnerable to heat and humidity, and so should be inspected frequently at authorized service centers or reliable workshops.