Portable jump starter not charging: How to fix?

(Last Updated On: March 13, 2024)

A portable jump starter is designed to help you in emergencies. But what happens when this device itself malfunctions? Even though reasonably priced portable jump starters are available, continually buying new ones is not a cost-effective solution—especially if the jump starter lets you down during an emergency.

The good news is, you can fix a portable jump starter—and we’re going to tell you how. But first, let’s talk about how the jump starters work, how long they usually last, and what you can do to keep them ready for an emergency.

How long does the average jump starter last?

In the long-term, the average portable jump starter will last anywhere from 6-10 years. Basically, they’re portable batteries, and their average maximum lifespan is similar. 

How to Fix a Portable Jump Starter
These guys are life-savers, but they can also break!

As far as how long they’ll last between charges, that depends on a lot of factors. The self-discharge rate of a battery or portable jump starter goes up with the temperature. The hotter it is, the more power it will lose. Keep that in mind if you store your portable jump starter in the trunk, where it can get very hot in the summer in direct sunlight. 

The maximum capacity of the jump starter will also determine how long it lasts between charges. Most will hold enough charge to jump-start a vehicle for 3 months between charges. Others can last up to 6 months or more, but as a rule of thumb, you should check the charge of your jump starter every 3 months. 

Tips for Extending the Life of your Jump Starter

So how do you make sure your jump starter is ready when you need it? Before we get into repairs, here are a few simple things you can do to keep your jump starter in working order:

  • Keep it charged. This isn’t just to make sure the jump starter has a charge when you need it. Deep discharges damage batteries, reducing their overall capacity. Keeping the jump starter as close to full as possible is the best way to avoid this and extend its lifespan.
  • Charge it immediately after every use. Starting a car takes a lot of energy, and that means a big draw off of your jump starter’s stored electricity. Recharge the portable jump starter after every use, even if it hasn’t been a full 3 months, to avoid over-discharges. 
  • Protect it from heat, cold, and moisture. Anything that damages a battery will also impair the performance of a jump starter. Moisture can lead to corrosion, which reduces the jump starter’s ability to transfer electricity. As mentioned above, heat speeds up the self-discharge process, which can also increase sulfation and cause other damage to the battery. Conversely, extreme cold reduces a battery’s ability to produce energy, so it’s also important to protect it from extreme cold.
  • Store the jump starter securely. If the jump starter is rattling around in your trunk, it’s more likely to be damaged than if it’s secured in place. Tying it down and keeping all the cables wrapped up is the best way to avoid problems.

How to Fix a Portable Jump Starter: Step-by-Step

You’ve followed the tips above—but you still find your jump starter won’t turn on when you check it. What do you do? Let’s walk through the troubleshooting and repair process. 

What you’ll need:

  • Basic tool kit (screwdriver, wrench, etc.)
  • Pocket knife or another small knife
  • Electronics cleaner
  • Soldering gun (if replacing battery cells)

Step-by-step guide on how to fix a portable jump starter

  1. If the jump starter won’t turn on, there is a chance it’s simply completely depleted. Try plugging it into the wall to charge it. If it won’t charge, test if the charging cable itself is the problem by using it to charge another device. Replace the charging cable if necessary; should both the charging cable and outlet work correctly, move on to the next step. 
  2. Visually inspect the external housing of the jump starter. If you see any areas that look melted, cracked, or warped, the jump starter may have sustained catastrophic damage from overheating or an impact. You may want to take your jump starter to a professional for repairs in this case. If you do repair it yourself, wear protective gear like gloves and eye protection. This kind of damage could indicate a leak or other damage inside the jump starter.
  3. Remove any screws holding the housing in place. If you don’t see any screws, you can make shallow cuts along any seams or joints you see until you’re able to open the casing. A flat-head screwdriver can be helpful for prying. 
  4. Examine the circuit board, battery cells, and terminals for signs of damage. If you see plastic shavings or wrappings on the circuit board, clear them away. You can also clean away corrosion or rust using a solvent approved for use on electronic components.
  5. Visually inspect all the wires inside the jump starter. Check if any are loose, and replace any that are frayed or show signs of damage. Also check the connector jack, which may melt if exposed to high temperatures. If it is melted or damaged, replace it. 
  6. If you don’t see any corrosion or damaged wires, the battery cells themselves likely need to be replaced. You can buy replacement cells from an electronics shop. Match the new cells to the old ones, to make sure they’re compatible. Remove the old cells and replace the new ones in the same sequence, then solder them into place. 
  7. Reassemble the casing once all your repairs are made. If you had to cut to open it, you’ll need to use glue or tape to keep it held securely together. 

If your jump starter still won’t turn on or charge at this point, there is likely an issue with the circuit board itself. While those can be replaced, at this point buying a new jump starter is probably your best bet. 

Here are some options to consider:
NOCO GEN Vs. GX: Which Battery Charger Should You Choose?    
NOCO Genius Vs. Genius PRO: Which Is The Better Battery Charger Series?
NOCO GB500 Boost Max Lithium Jump Starter Review
Best Schumacher Jump Starters (Review and Buying Guide)
NOCO GB50 vs. GB40 vs. GB70: Choose the best jump starter for your road trip
NOCO Genius1 vs Genius5 vs Genius10: Who’s the real “Genius”?

The Bottom Line

When you take good care of your jump starter, it will serve you well for as much as 10 years (or more). The most common problems jump starters face can all be fixed at home, including dead cells and broken or melted connectors.

If your jump starter isn’t working, open it up and take a look inside. Since it’s broken already, you have nothing to lose—and you might find the fix is both quick and cheap.

Bonus: Check out our Lithium Battery Charger review!

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