What to do When My Electric Mountain Bike Battery Dies

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An electric mountain bike is one of the most planet conscious methods of travel. It is also one of the planet’s safest means of moving around. No doubt, electric mountain bikes are known to amplify your pedaling power while increasing the amount of fun you have while biking. These bikes allow you to enjoy a satisfying amount of everything that makes mountain biking amazing. Apart from being small in size, sturdy and durable, an electric mountain bike is preferable, as your main mode of transportation, for any alternative.

If for whatever reason your mountain bike battery dies there are several steps you can take to resolve it:

  1. Let the battery and bike cool down.
  2. Remove and charge the battery properly.
  3. Turn the battery pack off. Wait several minutes and turn it on.
  4. Try your spare battery.
  5. Check the age of the battery.
  6. Jump-start the Battery Management System.
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Wanna know what happens when your mountain bike battery dies? Here is a guide through the world of electric mountain-bike batteries. In this article, you’ll find the different types of batteries used on electric mountain bikes, how to charge them, and how to solve common issues when your mountain bike batteries die. By the end of this article, you’ll know the basics of everything mountain bikes.

Important remark: Lithium-Ion (Li-Ion) and Lithium Polymer (LiPo) can be really dangerous and can explode when handled incorrectly. If you do not know what you are doing please consult a specialist.

Types of Electric Mountain Bike Batteries

Considering an electric bike, there are two major features that you should look at, they include- the motor and the battery. The motor controls how much power is delivered throughout the bike, while the battery is the beating heart of the bike. Without a good battery, the motor cannot function properly, and this affects the major purpose of having a pedal-assist bike in the first place.

Being the power source for uphill and flat-out single-track blasts, it is quite easy to recognize the battery as a fundamental part of any electric mountain bike’s system. So, if you are planning to cover long distances on your electric mountain bike, having a good battery with long life is essential. However, you may run into battery problems as this is mostly inevitable.

The first and important step here is knowing the type of battery that is most suitable for your electric bike, and how they are able to power the machine. For instance, there are some batteries that need be taken out of the bike to charge, while some require being left inside the bike.

There are two main types of batteries that are fitted to electric mountain bikes, they include Lithium-Ion (Li-Ion) or Lithium Polymer (LiPo) batteries. There’s a general belief that a lithium-ion battery is the best type of battery for your electric bike, however, there are types that also come in lead-acid and cadmium-nickel. In fact, there are several other types of batteries on the market today, but it’s important to know the most common ones.

What is a Lithium-Ion Battery?

A Lithium-Ion battery is a type of rechargeable battery that is usually much lighter than a similar-sized battery, especially when you compare it to the cheaper lead-acid type. Li-ion batteries are usually the most stable of all the batteries, which make them a little more expensive than the others. Asides these, they are easy to charge and tend to hold a charge for a long time.

What is a Lithium Polymer battery?

A Lithium polymer battery is a type of Li-Ion battery that is encased in a soft polymer shell. This soft polymer shell allows the battery to be more flexible, and this is why they are gradually becoming more popular for use on electric mountain bikes. Li-Po allows manufacturers to come up with ideas that will allow the electric mountain bike to look more like regular bikes.

What are the Common Problems of Electric Mountain-bike Batteries?

Electric bike batteries often have problems that fit into one of two categories:

  • Charging issues: in this case, your battery won’t charge or won’t hold a charge (for example, you charge it for about 10 hours and it doesn’t charge or is low).
  • Discharging issues: These come in two varieties as well, firstly your battery appears to be dead. When you take it out and reconnect it, it works again. The second one is that a fully charged battery dies very quickly.

Now, if you place your electric mountain bike battery on charge and it does not seem to charge, you may need to check the charger first. There are different ways to do this, you could use a light bulb and voltmeters to check. You can also check for a charger issue by trying to power your electric bike with the charger.

You’ll first need to remove the battery pack, then hook the charger directly up to the power wires. If doing this makes the power display to come on and the motor to spin with your wheel, then you may have a battery problem instead. If the charger passes the above test, this doesn’t mean that there is nothing wrong with it, we’ve only just made it less likely to be the charger. Next, you’ll definitely need a voltmeter test. These tests will work for both charging and discharging issues.

Diagnosing Your Mountain Bike Battery

There is an important tool you’ll need to diagnose your dead motorcycle battery, and that is a Multimeter. This tool will make you see the standing voltage of your battery. To diagnose, remove all the bodywork, and connect your Multimeter to your battery terminals. Always note that red is positive and black is negative. After connecting the leads, turn your Multimeter on and set it to read volts. (Some Multimeters auto-detect the voltage while others require setting— you can check your Multimeter manual to get a good idea for what settings you need).

On hardpack batteries, it is important that you first remove the battery from your bike. On the other side of your battery, you’ll find 2 to 4 or even 5 terminals where you can plug your voltmeter. (You can plug into any 2 of these terminals to get a reading). On soft pack batteries, however, you’ll see that manufacturers have included an XT-60 adaptor. You may see 2 cables that look the same. Just know that the XT60 is the larger of the 2 cables. Next, you’ll want to plug in your voltmeter.

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Once you’ve plugged it, if your battery reads above 35 volts, then it is good to go. If your battery is below 35 volts, you may need to give your battery a charge. If it reads below 27 volts, it means you need a new battery. Although your mountain bike may start with a standing voltage of 27 volts, it might be hard to start, and this can cause wear on the electrical system. But if you’re on a time crunch and need to get somewhere in a hurry, you can jump-start the battery.

How to Fix Your Electric Bike Battery if it Dies

If you want to fix your battery issues, you can either take it to your local dealer and have it fixed for a price, or you can take a little DIY time and fix it yourself.

  1. Cooled down: Make sure the battery and bike have cooled down. If you have asked a lot from your battery in a hot environment the battery and the Battery Management System can get very hot and even shutdown.
  2. Remove the battery and try to charge the battery properly. You can also double-check the battery charging procedure in your manual, and then plug the charger into your battery.
  3. Turn the pack off: If the battery pack has an on/off switch, turn the pack off. Wait for several minutes and turn the pack on again, and check if it works.
  4. Check the age of the battery, it can be that your battery is just too old and does not have enough capacity left. Normally you will notice this, similar to your phone battery, as it will last less and less. But there can be cases where you do not really notice this until you use it under different circumstances (like colder weather, different terrain). Batteries can only be changed a finite amount of time.
  5. Spare battery: If you have a spare battery, try if that battery works (make sure it is charged). If your bike does not run, there is probably something wrong with the electrical system on your bike. If the bike runs, your battery or the Battery Management System is probably broken or faulty. As lithium-ion and lithium polymer batteries are really dangerous it is advisable to replace it. Don’t forget to check your manual if this can be done under warranty.

There are certain battery packs that can be full and still do not work. A spark can cause the Battery Management System to shut down the battery pack and enter a sort of fault mode. If this is the case there is a trick to jump-start the pack.

How to Jump-Start your battery pack

Before continuing: jumpstarting a battery pack is dangerous and should only be done by somebody that knows what he is doing. If something goes wrong your battery can explode.

Some battery packs, like the Luna Shark Battery pack, do not have an on/off button to rest the battery pack. When the Battery Management System detects a spark or another strange condition it can turn itself off. Similar to your surge protection in your home. Not having an on/off button or switch means that you can not reset the Battery Management System and the pack is dead.

of the battery pack has entered a fault state it is not possible to reset it. To resolve this, you’ll need to try a jump-start your battery for just a few seconds. Think of it as using a defibrillator on the heart.

The exact procedure depends on the battery pack and involves using another power source. This can be a power supply or even another battery. After jump-starting, you’ll want to charge your battery normally. As a result, your battery should charge and then discharge normally once you’ve put it back on your bike. Always remember not to use the discharge port for more than a minute for charging as it can cause a series of problems. Especially burning your house down.

If jump-starting still doesn’t work, you may need to look into advanced options that involve cutting your battery open. Naturally, that’s not something you want to be doing as it is a job for experts. Also, you wouldn’t be reading this guide if you know how to do that. So, you will need to revisit option 1: Take your electric bike back to a dealer. This time, they will have to decide if your battery can be saved or if you need to get a new battery instead.

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Final remarks

We hope that this guide has been helpful in fixing the basic problems you tend to encounter with your electric mountain bike battery. Good luck!