The interior of a car can reach 70-80°C (158-176°F) on a hot sunny day without too much trouble. But even if the battery pack doesn't set your car on fire, it's still a bad idea to keep it inside the car because heat will degrade Li-Ion cells. If you store a fully charged battery at high temperatures, that's one of the best ways to kill it. Most Li-Ion batteries specify a maximum storage/discharge temperature of 50-60°C (122-140°F).
If you live somewhere that doesn't get extremely cold winters, and your car battery is in good shape, and there is nothing wrong with your car, there isn't really a reason to keep a car battery booster pack around.
Storing a jump starter in the car is perfectly fine, especially with the newer lithium-ion batteries that are much more compact than the older, bigger lead-acid jump starters. There's no safety risk, although extremely cold temperatures may weaken the battery, so make sure that you check your car battery jump pack regularly.
Here are a few factors to consider when you need to keep a portable car battery jump starter in car:
- Temperature: car jump starters typically contain lithium-ion batteries, which are sensitive to high temperatures. If a power bank is exposed to extreme heat inside a car, it can lead to thermal runaway, causing the battery to overheat, leak, or even catch fire.
- Direct sunlight:Prolonged exposure to direct sunlight can significantly increase the temperature inside a car, leading to potential damage or malfunction of the power bank. It is advisable to avoid leaving any electronic devices, including car battery jump starter pack, in direct sunlight.
- Safety precautions:Car jump starters should be handled with care and stored properly to prevent physical damage or short-circuits. Leaving them loose in a car's cabin or trunk increases the risk of accidental impact or damage, which can compromise the battery's safety.