How to Charge eBike Battery without Charger?

A mechanical engineer became an active blogger, and it’s James Miller. Well, the journey of his blogging started more than a decade ago. As a...Read more

Are you miles away with your electric bike and you forgot your charger back home. Maybe the charger is broke and you just can’t get another right now? There’s nothing more irritating than not being able to use your e-bike only because you don’t have a charger.

Turns out, you can charge your ebike battery even without a charger! Of course, it won’t be the standard charging procedure as a charger would offer. All you need to know is how to charge ebike battery with key, with some safety precautions.

We’re discussing exactly that today. We’ll look into the major and minor details of charging ebike battery. You’ll also get to know the rules and regulations that come into place.

Key Takeaways:

  • Charging e-bikes without a charger isn’t an easy task. However, it can be done by two methods- car’s battery and power supply.
  • Charging regularly without the original charger may damage the battery life.
  • You can find different charging options while riding off-shore and run out of charge.

Charging with The Car Battery

Charging from the car battery is the safest option available other than charging directly from your e-bike charger. For doing that, you have to make some setup. Once you make the setup, you can easily charge your e-bike without any charger.

Even if you’re on a road trip long outside your house. However, your battery must be removable, or it would indeed be challenging to make this process work.

Charging with The Car Battery

Step 1: Gather Things

You have to buy an inverter that will not cost more than 100 bucks. You will need a power tracking device just to tell you that it’s working. Lastly, you would need a Powerfix battery level tracker. That tells you the state of the battery.

Step 2: Check the Connection

Now, connect these devices with your car’s battery and see if the light is on, indicating that you’re up and running. Once the green light is on in the Powerfix, it’s ready to roll!

Step 3: Charge the Battery

Now, just plug in your e-bike’s battery and you’re all set! Once you confirm your battery is taking charge, you can put it there and even go for a walk. Mostly, all the batteries of e-bikes are lithium-ion batteries. So do not necessarily fear the overcharging issue. Once the battery is fully charged, it will stop taking charge automatically!

Safety tips: I don’t know if there are any bikes that have lead-acid batteries. If you’re holding an ebike with a lead-acid battery, which I believe you don’t, you have to make sure you’re standing there until full charge.

Pro tip: Start your car’s engine to charge the e-bike’s battery fast and efficiently.

Charging via Power Supply

Charging your ebike battery from a power supply is like charging your smartphone via a USB cable. Unlike smartphones, it requires extreme care. It also requires a lab bench power supply with a steady current and voltage.

Step 1: Set up The Voltage

Once you get the power supply, it’s time for you to start the process by setting up the voltage. Most e-bikes are built with a lithium-ion battery, and that requires 4.2V. If your battery isn’t lithium-ion, then see the battery voltage printed on its body and set it accordingly.

Step 2: Set the Current

Set the current to around a tenth of the battery’s capacity in Amp-hours. This is necessary because you need to supply only the right amount of power through the battery terminal.

Step 3: Check the Voltage with Multimeter

Measure the battery voltage with a multimeter before connecting the power supply leads to the battery terminals. If the battery’s Open Circuit Voltage is the required 4.2 Volts, you can safely charge it. It will take around 10 hours to be fully charged.

Safety tips: Never leave the charging setup alone. Sometimes it might get overheated. You have to immediately plug it off in such cases.

How to Charge Your Ebike Battery if You’re Off-Grid?

People who use the e-bike for mountain hiking rather than regular commuting face this problem often. It’s no big deal if you’re far for a few miles from your home. However, it is a tense situation when you’re in the middle of a mountain and far away from your home. I have a few solutions for you in case this happens to you.

How to Charge Your Ebike Battery

Find a Power Station

There are lots of power companies building small power stations in remote areas. You can simply search on the map for the nearest power station. Once you find one, go there and plug it in for free. Have a walk until your battery gets fully charged or whatever charge you need to get back in your tent.

Power Station

Find a Church

Church is a very helpful place to go for charging your ebike battery. This is applicable for either you’ve left with less charge, or have no charger on you at all. iF the church has a charging booth, that’d be your best chance. You can stay there until your battery gets fully charged. And guess what? You don’t need to pay a dime for that.

Find Nearest Restaurants or Pubs

When you wouldn’t find a power station or a church, restaurants or pubs come into handy. You can look for the nearest restaurant and walk there to seek help. But let me tell you, they aren’t there for charity. You might need to buy something to stay there for a while and get your thing done!

When Do I Charge My Electric Bike?

Simply, you charge your battery when you’re out of power. But leaving your electric bike’s battery entirely blank isn’t a wise choice. It will harm your battery life, and therefore you will lose it at the earliest.

Always try to charge your battery before it runs out entirely. You should fully charge your battery every day. Charging for random hours could also harm your battery. At least charge them for 4-6 hours until full charge.

Should I Charge My Ebike Battery Without Charger?

If you have your manufacturer-provided charger with you, then it is wise to charge with it. But in an emergency case, you can use the car’s battery or power supply to charge your e-bike’s battery.

Remember that charging in conventional ways is not recommended by manufacturers as it may damage your battery slowly. To keep your battery healthy, always charge with the regular charger.

In case you lose it, let your manufacturer know and order another one. They will surely provide you with the best.

What Happens If I Charge My Ebike Battery Without A Charger?

If you don’t charge the battery with the proper charger, it will eventually lose its ability to hold charge for a long time and will need to be replaced soon. It is not wise to charge without the conventional charger regularly.

If you lost your charger, bring another one immediately to keep your battery safe. Who would want to lose their battery over a little-pricey charger? However, it won’t damage much if you charge without the charger only in emergencies.


Now that you know how to charge ebike battery without charger, you won’t get stuck while you’re out there without charger on you. However, it has some serious harmful effects if you regularly charge in such methods. It can harm your battery life as well as battery mileage.

However, these methods will be handy in emergency situations and help you recover efficiently. So, if you’re an offshore enthusiast, make use of any of the methods that would suit you perfectly from the above-mentioned ones.

A mechanical engineer became an active blogger, and it’s James Miller. Well, the journey of his blogging started more than a decade ago. As a mechanical engineer, he started his professional career as a technical assistant in a renowned automotive industry and later joined an e-bike manufacturing company as a quality in charge. James created this site “Bikerreview” to share his decade of experience with e-bikes. He wants to help the people who are newly looking for an e-bike and doesn’t have any prior knowledge about that.

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