Electric vehicles like Teslas rely on lithium-ion batteries to power the car. There has been some concern that hot temperatures can cause faster battery drain and reduce driving range. In this article, we’ll look at how heat impacts Tesla batteries and what drivers can do to maximize battery life and driving range in hot weather.
Do Tesla batteries drain faster in heat?
Yes, heat does tend to increase the rate of battery drain in Teslas and other electric vehicles. There are a few reasons for this:
- Chemical reactions inside lithium-ion batteries speed up at higher temperatures. Faster chemical reactions lead to faster battery drain.
- The electrolyte fluid inside lithium-ion batteries becomes less efficient at conducting electricity when hot, forcing the battery to work harder.
- Tesla battery management systems take steps to actively cool down the battery when it gets hot. This battery cooling requires extra energy use.
Research has found that a Tesla battery can lose around 1% of its range for every 3°C (5.4°F) of increase in ambient temperature above 20°C (68°F). So in very hot 50°C (122°F) weather, a Tesla might lose 10% or more of its range.
How much range loss is typical in hot temperatures?
The amount of driving range loss in heat depends on factors like:
- How hot is it? – Range loss increases significantly at temperatures over 35°C (95°F).
- How is the car used? – Aggressive acceleration and driving up hills uses more battery.
- Is cabin air conditioning used? – A/C requires battery power to run.
- Does the car sit in the sun? – Interior temps can become extremely hot.
- Battery size – Larger batteries have more thermal mass and are less impacted.
Under real-world mixed driving conditions, most Tesla owners report an average range loss of 10-25% in very hot weather over 35°C (95°F) compared to more mild temperatures. Aggressive driving can shorten range further. Parking the car in the shade helps minimize heat buildup.
Does battery drain stabilize after driving for awhile?
Yes, the rate of battery energy drain in a Tesla does tend to stabilize after driving for awhile. Here’s why:
- The battery reaches a stable operating temperature after heat soaking while driving.
- The cabin cools down reducing A/C power draw.
- Tesla battery management systems scale back cooling efforts once a stable temp is reached.
So while range may be lowest immediately after driving starts in hot weather, the rate of energy use should stabilize after about 20-30 minutes of driving time. However, total range will still be reduced compared to cooler conditions.
Does parked Tesla battery drain faster in heat?
Parked Teslas do see more passive battery drain in hot weather compared to cool temperatures. For example, Tesla reports that its cars have average idle battery drain of just 1% over 24 hours when parked. However, parked drain can double to 2% per day in very hot climates.
Reasons parked Teslas have higher drain in heat include:
- Battery cooling systems activate more frequently to prevent heat damage.
- Some automatic background processes like data logging may run more often.
- Chemical reactions in the battery speed up.
To minimize parked battery drain, avoid leaving Teslas sitting in the sun or use solar shades to keep the interior cooler if possible.
How Much Battery Drain is Normal When Parked?
| Ambient Temperature | Expected Battery Drain |
| Under 21°C (70°F) | 1% per day |
| 21° – 38°C (70° – 100°F) | 1-2% per day |
| Over 38°C (100°F) | 2-4% per day |
Does AC use impact Tesla battery life?
Yes, running the air conditioning in a Tesla can indirectly reduce range and battery life over time. This is because the A/C compressor and fan use energy from the battery pack. Some estimates indicate the A/C can use 5-10% of battery capacity just to cool the cabin on hot days.
Driving with the windows down avoids using the A/C compressor, but reduces aerodynamics and wastes even more energy at highway speeds. So it’s generally most efficient to use A/C when needed, even though it cuts into battery range.
Do high temperatures damage Tesla batteries?
Extreme high temperatures above about 60°C (140°F) can start to damage Tesla lithium-ion battery cells. However, Teslas have robust thermal management systems to proactively cool the battery and prevent overheating damage:
- A liquid cooling system circulates chilled coolant to remove heat.
- Cooling plates and fins help transfer heat out of battery cells.
- The battery management system will limit power during excessive heat as a protective measure.
As long as the cooling systems are operating normally, the battery should stay in safe temperature ranges even in hot ambient conditions. Most battery damage from heat is seen when cooling systems fail or are overwhelmed.
Tips to Reduce Tesla Battery Drain in Heat
Here are some tips Tesla owners can use to maximize battery life and driving range during hot weather:
When Parked
- Park in shade or use solar reflective windshield sunshades.
- Set climate control to keep the cabin cooler.
- Schedule charging to complete just before departure to minimize idle time.
- Consider a lower state of charge target if parked for weeks.
While Driving
- Reduce energy demands by using chill mode and limiting acceleration.
- Crack windows instead of heavy A/C use when comfortable.
- Travel shorter distances and minimize stops to keep moving.
- Plan a route with more downhill sections to help regenerative braking.
General Tips
- When possible, avoid peak heat by running errands early or later in the day.
- Use darker tinted windows to help reflect sunlight.
- Get a ceramic coating or window tints to reduce cabin heat soak.
- Stay within speed limits and drive efficiently to reduce energy use.
Conclusion
In summary, Tesla batteries can experience greater energy drain rates in hot ambient temperatures, potentially reducing range by 10-25% or more compared to cool conditions. The impacts are more pronounced at extremes over 35°C (95°F). However, Tesla’s thermal management and battery systems are designed to keep temperatures within safe limits and avoid heat damage, even in hot climates. With smart charging, parking, and driving practices, Tesla owners can maximize driving range and battery life through hot summer weather.