Is It Safe to Leave a Jump Starter in Your Car? A Quick Guide for Drivers

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Is It Safe to Leave a Jump Starter in Your Car

Is it safe to leave a jump starter in your car? Keep your battery charged and your mind at ease with the right information.

Have you ever found yourself stranded on the side of the road with a dead car battery? It’s a frustrating experience that can leave you feeling helpless. As a driver, I always want to be prepared for any situation on the road. That’s why I carry a jump starter in my car, just in case my battery dies unexpectedly.

But is it safe to leave a jump starter in your car all the time? The answer is Yes, in most circumstances. But there are some caveats. In this quick guide, I’ll answer that question. I’ll give you the information you need to keep your jump starter safe and ready to use when you need it.

Key Takeaways

  • Keep a jump starter in your car, but be mindful of factors such as temperature and moisture.
  • Safely storing a jump starter is crucial for the tool’s performance and lifespan.
  • It’s important to follow the manufacturer’s instructions for the proper use and storage of the device.

Is It Safe to Leave a Jump Starter in Your Car

Let’s have a look at the pros and cons.

Convenient in case of emergencyRisk of battery drain
Always available when neededSafety risks if not stored properly
Can help others in needRisk of theft or damage to the jump starter
Peace of mind and independence, reducing reliance on othersMay not be suitable for extreme temperatures
Can be used for other purposes, such as charging devicesMay require regular maintenance and monitoring

When it comes to keeping a jump starter in your car, there are both pros and cons to consider. I’ve compiled a list below to help you make an informed decision.


  • Emergencies: A portable jump starter can be a lifesaver during those unexpected moments when your car battery dies. Trust me, it’s better to have it in your car than in storage!
  • Independence: No need to rely on strangers to help you jump-start your car. I can’t emphasize enough how convenient this is for me. And I am always ready to offer assistance to others who may need it.
  • Compact size: Many jump starters are small enough to fit in your car without taking up much space.
  • USB Ports: They almost always have USB ports, which you can use to charge other devices. This alone has gotten me out of a couple of scrapes.


  • Temperature sensitivity: Some lithium-ion batteries can become dangerous at high temperatures, like the 60ºC (140ºF) threshold for thermal runaway.
  • Battery maintenance: You’ll need to periodically recharge the jump starter, even if it’s not in use. This is because of the phenomenon of self-discharge. All batteries lose charge over time, even when unused.

As you can see, there are pros and cons to keeping a jump-starter in your car. Geographic location, climate, and the type of battery technology your jump starter uses can all influence whether it’s a wise choice for you.

Factors to Consider When Leaving a Jump Starter in Your Car

Remember those pros and cons we talked about? Let’s go deeper.

Temperature and Climate

One important factor to consider is the temperature and climate. High temperatures can damage lithium-ion batteries. During summer, the inside of your car can get very hot. It’s safer to keep the jump starter in a cool area, like a garage. This will keep things nice and safe, and jump starters are small enough to grab and go when you’re off out.

In cold weather, the battery can get affected too. Anything under 32ºF can adversely affect your battery. Just be mindful of extreme temperatures when storing your jump starter in the car.

Battery Life and Maintenance

Keeping your jump starter charged is essential. A dead jump starter can’t revive a dead battery. Remember to check its charge regularly and charge it when you need to. It is important to remember not to leave it in your trunk for ages and assume it will work when you need it.

Mitigating Safety Concerns

There are safety concerns when storing a jump starter in your car. Lithium-ion batteries can experience thermal runaway. This leads to overheating and can be hazardous.

Most Li-Ion batteries can handle up to 122-140°F. Unfortunately, car interiors can reach up to 158-176°F on hot sunny days. That’s not safe for your portable jump starter.

You want to avoid leaving it exposed to direct sunlight. Keep it in a shaded spot, like the glovebox, under a car seat, or in the trunk. This will help keep the temperature down. Better still, keep it in a garage to keep it cool and grab it on the way out with your keys.

Although the chances of something bad happening are low, it’s better to err on the side of caution.

Pro tip: Look for jump starters that use LiFePO4 (lithium iron phosphate) batteries. These batteries are safer and more stable in hot temperatures.


Lastly, think about security. Keep your jump starter in a safe place. Hide it from prying eyes and potential thieves. I always keep my jump starter in the trunk or glove box so it isn’t visible to opportunist thieves.

Charge It Regularly

A jump starter won’t be helpful if it’s not charged. Make sure to check the battery level regularly. Connect it to a USB port or wall charger to top it off. Don’t forget to unplug it once it’s fully charged.

By following these steps, you reduce the risk of damaging your jump starter. By avoiding heat and moisture, you can keep it functioning well for a longer time.

Which type of Lithium Battery for Me?

Did you know several types of lithium batteries are used in car jump starters? Not all are created equal in the way they react to temperatures. Let’s take a look at the main ones.

Lithium-ion Batteries: The Temperamental Ones

Lithium-ion batteries are like the friend who gets moody when the temperature changes. They’re often used in jump starters because of their high energy density and long cycle life. But they can be sensitive to temperature changes.

When exposed to high temperatures, they can experience thermal runaway. In turn, this can lead to swelling, leakage, or even a big bang. Store them in a cool, dry place to keep them happy and avoid exposing them to extreme temperatures.

Lithium-polymer Batteries: The High-Maintenance Ones

Lithium-polymer batteries are like that high-maintenance friend who always needs extra attention. They have a gel-like electrolyte that can expand when heated. This can lead to internal pressure buildup and swelling or explosion.

High energy density and low profile make them popular. But they are also more prone to swell and explode due to high temperatures than Li-ion batteries. Store them in a cool, dry place to keep them happy and avoid exposing them to extreme temperatures.

Lithium Iron Phosphate (LiFePO4) Batteries: The Reliable Ones

LiFePO4 batteries are like that reliable friend who always has your back. They can withstand high temperatures and are a safer option for leaving in your car.

They have a higher thermal stability than other types of lithium batteries. So they are less prone to thermal runaway or explosion.

Battery TypeTemperature RangeOptimal Performance
LiFePO4-20°C to 60°C (-4°F to 140°F)0°C to 45°C (32°F to 113°F)
Lithium-ion 0°C to 45°C (32°F to 113°F)15°C to 35°C (59°F to 95°F)
Lithium polymer-10°C to 50°C (14°F to 122°F)10°C to 40°C (50°F to 104°F)

Final Recommendations

  • Check your jump starter’s temperature range and follow proper storage guidelines.
  • Instead of leaving it in your car during hot weather, bring the jump starter inside.
  • Regularly inspect your jump starter for signs of damage or wear.
  • Ensure your car has proper ventilation to avoid extreme temperature fluctuations.

By following these tips, you can make the most of your jump starter while keeping it safe and effective.

Before You Go …

Before you go, let me remind you that jump-starting your car is only half the battle. To ensure that your car is running smoothly and safely, it’s important to follow the proper procedure after a jump start.

In our next article, “How Long Should You Drive After a Jump Start? Don’t Make This Huge Mistake,” we’ll explain why this step is so crucial and what can happen if you don’t do it.

Don’t risk leaving yourself stranded on the side of the road. Click on the link and read on to learn how to jump-start your car properly.

Frequently Asked Questions

Here’s the FAQs

Can I store a jump starter in my car’s trunk during extreme temperatures?

Yes, you can store a jump starter in your car’s trunk. However, be mindful of the temperature range. Most jump starters are rated for up to 140°F. If you live in a hot climate, check the temperature limits of your jump starter.

How long can a jump starter be left plugged in?

While charging times vary, don’t leave your jump starter plugged in for too long. Overcharging may cause damage. Check the user manual for guidelines on how long to charge it.

Do lithium jump starters pose a safety risk?

Lithium jump starters are generally safe. Quality jump starters have built-in safety features. But, like any device with a battery, always handle it with care and follow the manufacturer’s instructions.

How frequently should a jump starter be recharged?

A jump starter should be recharged every 3-6 months. Keep it topped up to ensure it’s ready if you need it.

Are portable jump starters safe for use on all vehicles?

Portable jump starters work on a variety of vehicles. However, double-check your owner’s manual. Some manufacturers don’t allow jump-starting, and doing so might void the warranty, says YourMechanic.

What factors affect the longevity of a jump starter battery?

Temperature and usage matter. Extreme temperatures might shorten the battery life. Storing your jump starter properly and recharging it regularly will help. Avoid letting it sit for long periods without use.

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Steve Brown


Steve is a gadget enthusiast who's always been intrigued by batteries. The founder and editor of Battery Chargers Info, he's assembled a group of like-minded experts to cover every facet of portable power His aim is to help you learn more about your favorite gadgets and their batteries so you can maximize both their performance and their life. Follow him on Twitter: @batterycharge1

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