Batteries are the most expensive and essential parts (lifeline) of an electric bike as it powers the entire bike but what if the battery dies suddenly while riding an ebike?
Would you be able to ride it again using the battery power? Well, the answer is NO! You can’t turn on the battery if it dies without reviving it. You need to revive your dead battery and then charge it. But how?
Reviving and charging a dead ebike battery is very complex and dangerous too. But don’t worry I have explained the process step by step of How to charge a dead ebike battery after reviving it.
Along with that, I have also covered the common causes of dead ebike batteries and how you can prevent your battery from being dead.
Read this article to learn more about e-bike batteries, the charging process of dead e-bike batteries, and tips to make them last longer.
Dead Ebike Battery: What it Means
An ebike battery is called dead when the battery’s electric power (voltage) comes down the minimum voltage limit and is thus not able to power the ebike or any electrical device. Therefore, a dead battery cannot restart the electric bike.
Symptoms of a dead ebike battery
As I have already mentioned that a dead ebike battery does not have the minimum power to restart anything. So when your ebike battery is dead, your ebike display, headlights, motor, throttle, and many more electric devices of ebike will not turn on.
Hence, you won’t be able to restart your bike using the battery because the battery has become dead and is not capable enough to supply the power to the motor to assist you while pedaling.
We will surely discuss the possible reasons why ebike batteries become dead but before that, let’s know whether you can charge your dead ebike battery or not.
Can you charge a dead ebike battery?
If your ebike battery is dead, you can’t charge it normally as you always do. It means you can charge a dead electric bike battery but there is a different method to do it.
Actually, when the battery is dead the BMS of that battery stops receiving and supplying the electric power and hence you are not able to charge a dead battery normally.
Therefore, you need to open the battery and cut out (exclude) the BMS and then charge the battery to the minimum voltage level then you can connect it to BMS again and recharge it normally.
But this process is not as easy as it sounds because this process is very risky and may lead to the ebike battery catching fire or exploding. Scroll down to learn the entire process of how to charge a dead ebike battery step by step.
Can you revive a dead electric bike battery?
Reviving your electric bike battery means trying to restore the battery and fix the problem. Yes, it is possible to revive a dead e-bike battery by charging the battery with its compatible charger.
But there is some twist in the process, otherwise, your battery won’t revive.
You need to remove the battery management system from the charging line. I have explained the process in detail of reviving a dead ebike battery later in this article. But before that let’s know what are the reasons that cause ebike battery dead.
Why Does an Ebike Battery Dies? Common Reasons
There are a lot of reasons why your e-bike battery is dead such as an incompatible charger, undercharging the battery, exposure to extreme weather, and so many more.
1. Exposure to Extreme Weather
It is one of the suspected causes of dead ebike batteries because ebike batteries are built to survive in extreme environmental conditions, but if you give your battery extreme exposure and keep it in an extremely hot or extremely cold environment, it will affect the battery’s temperature and lifespan.
Therefore, It’s suggested that you don’t ride the electric bike in the rain or snow and store it at room temperature, or 40–60 degrees Fahrenheit. (Source)
2. Undercharging the Battery
How much you charge the battery also determines and affects the overall lifespan and performance of the e-bike battery. It is recommended to charge the battery after every ride to ensure its longevity if the battery level is around 20% or 30%.
Don’t let your battery deplete completely or drop below 20% – 30%. If you are not using the bike, even then don’t let it completely discharge.
3. Damaged and Poor BMS
A BMS, or battery management system, performs many functions and protects the battery from catching fire or exploding. The BMS controls the charging and discharging of the e-bike battery.
If this battery management system fails and gets damaged or breaks, it makes the ebike battery dead and thus affects the overall performance of the battery and can reduce its lifespan.
4. Battery’s Lifespan
There is no doubt that lithium-ion batteries are one of the best ebike batteries used in electric bikes. But these batteries also have a lifespan, and after every charge, they degrade.
Generally, Lithium-ion batteries last up to 500 to 800 charge cycles and more or have a lifespan of about 3 to 5 years, whichever is earlier. If your battery has completed its lifespan, it is more likely to be dead.
5. Overload on the Battery System
It is important to understand that e-bikes also have power limits; if you keep overloading them, it will impact the battery and its lifespan in the long run or also degrade the battery faster.
E-bikes work well if you use them moderately without overloading them. Don’t be too hard on them otherwise, they may catch fire or become dead.
6. Due to Cheap-Quality Charger
When you charge your battery with a local charger, it rather transfers current to the battery fastly or very slowly as a result it damages the cells or the entire battery pack including the BMS, and hence the battery becomes dead.
How to Charge a Dead Ebike Battery?
Warning: reviving a battery with a jump starter is very risky and it may cause your ebike battery to catch fire or explode if something goes wrong. Don’t do this process unless you know what’s right and wrong.
We are going to revive the dead electric bike battery so we need some tools for this process. I have got a charger, screwdriver, and a voltmeter. Follow the following steps:
Step 1: Take out the battery off the ebike & remove its cover
The first step is to take out the battery and remove the cover using a screwdriver. Take out all the volts carefully and put rubber gloves on your hands so that you don’t get shocked.
Step 2: Measure the voltage of the battery
The next step is to measure the voltage of the battery using a voltmeter from the BMS side. You need to place the positive probe on the positive end of the BMS and the negative probe on the negative end of the BMS.
Step 3: Measure the voltage of each cell
Also, measure the voltage of all the battery cells one by one and find out the lowest voltage cells. Using the voltmeter, place the positive probe on the positive end of the cell and the negative side on the negative end of the cell.
Once you find the cells with the lowest voltage, mark them using a pen or marker.
Step 4: Disconnect the Battery Management System (BMS)
Once you have identified the cells with low voltage in the battery pack the next step is to disconnect the BMS from the battery pack so that it doesn’t stop the inflow of current to the battery pack while reviving the battery.
Step 5: Start charging all the cells
The next step is to charge the cells slowly using a low-amp charger. There are two ways to charge the cells, the first way is to charge the cells separately using a slow charge but it’s time-consuming and needs some specialized devices.
So it’s best to go with the second method in which we would connect the charger directly to the entire battery pack and charge the cells at a low charging rate.
Do charge your battery to 50% only because the rest of the charging will be done using the BMS.
Step 6: Reconnect the BMS to the battery pack
Simply reconnect the BMS by attaching the wires to the negative and positive terminals. And check whether the required voltage has crossed the minimum voltage from the BMS points.
Step 7: Put the battery cover and reattach it to the ebike
And in the final step, you just have to put the battery cover and reattach the battery to the bike frame and connect the required wires and try to restart the ebike. If your bike display starts working, it means your dead battery is revived.
What to do if the dead ebike battery is not revived after applying the above process?
Yes, there is a possibility that your dead ebike battery may not get revived after applying the process. And this may happen due to various reasons such as:
- The battery has completed its lifespan (replace the entire battery),
- Few cells could be damaged completely (need to replace them),
- Due to some loose connections or you are using a local or damaged charger
So make sure to check and tick these points before proceeding further.
How long does it take to charge a dead ebike battery?
Charging a dead ebike battery is a time-consuming process because you have to follow the above steps which may take around 4-5 hours. Once you are done with this process, then you have to charge the battery for 4-6 hours as you always do.
So, overall it would take around 10-12 hours for charging a dead electric bike battery. You can reduce the charging time if you charge your battery with a high-amp charger. But I don’t recommend it.
How to Prevent a Dead Ebike Battery? 5 Tips
- Give a regular charge to your e-bike battery; don’t overcharge it, but whenever you come home after riding your e-bike, don’t charge it immediately as it is heated.
- Utilize pedal assist mode while riding; it will help reduce battery strain and also add extra power to your pedaling.
- Avoid e-bike battery exposure to extreme heat and high temperatures, as most e-bikes have lithium-ion batteries that are sensitive to extreme temperatures.
- Keep the battery free of any kind of dirt or debris. By doing this, you are ensuring that your e-bike and battery have a good connection.
- Avoid fully discharging your battery, as if you charge a fully discharged battery, it will use one charging cycle. You should not let your battery discharge completely (not less than 20%).
You can charge your dead electric bike battery using a jump charger and jumping cable with another live bike. Follow all the tips we discussed above.
As a quote says, “Precautions are better than cure,” “so you must take all the necessary precautions and take care of your electric bike and its battery properly to make it last longer.
Must know: What is Ebike Battery Voltage Sag?
FAQs: How to Charge a Dead Ebike Battery after Reviving It
Can you ride your electric bike with a dead battery?
Yes sure! You can ride your electric bike with a dead battery by pedaling only. The only thing is that you would not be able to use the throttle or pedal assistance when your ebike battery is dead because the battery is not capable enough to turn the motor, or even lights on. Therefore, in that case, you have to pedal hard in order to ride your ebike.
What to do if your ebike battery dies while riding?
When your ebike battery dies while riding, your motor will turn off. The very first thing your should do is to park your bike at a safe spot and check the battery for any damage.
If your battery is extremely heated, it may be dead. Turn off the battery and try pedaling your bike if you can or push your ebike home.
Can you recharge a dead ebike battery?
Yes, but you need to revive it first. Learn more in step-by-step guide!
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