How to Properly Care for Your E-Bike Battery and Charger

With the increase in e-bike popularity, there's been more attention on the proper care and handling of lithium batteries - particularly following some well-publicised e-bike battery fires in 2023. Though these cases are rare, taking care of your battery and charger is essential for both safety and keeping your bike in top condition for as long as possible. Here’s a guide on what you need to know about looking after your e-bike’s power source.

What Causes E-Bike Batteries To Catch Fire?

In almost every case, lithium-ion e-bike battery fires are caused by thermal runaway, where a rapid increase in temperature and pressure releases flammable gas that can ignite.

This usually occurs due to three main reasons. The use of low-quality batteries, often due to cost-cutting manufacturing practices, can lead to defects like bulging and eventual rupture. Be wary of very cheap e-bikes, as these often skimp on quality and may pose serious safety issues. Additionally, physical damage, and improper charging practices - such as using a different charger in an attempt to fast-charge the battery - can raise the risk of fires.

However, with high-quality batteries that are properly maintained and handled, the risk of something going wrong is very low. When choosing quality and following safety guidelines, riders can confidently enjoy their e-bikes with minimal concerns.

Understanding Safety Marks: UK CA and European CE

Before we get into the nitty-gritty of battery care, it’s worth noting that your e-bike’s battery and charger should carry either the UK CA mark (post-Brexit) or the European CE mark. These symbols show that the products meet strict safety standards, so it’s important to check for these when purchasing an e-bike or replacement parts.

Charging Your E-Bike Battery

One of the first things you’ll do when you get a new e-bike is charge the battery, but there’s a correct way to do it that’s often overlooked. Always connect the charger to the battery first before plugging it into the mains. If you do it the other way around, there’s a chance you could short-circuit the system, which might blow a fuse or damage the charging port on the battery itself. And remember, once charging is complete, turn off the charger at the mains before disconnecting it from the battery.

When you plug in the charger, you’ll usually see a red LED light, indicating that charging is in progress. Once it turns green, your battery should be fully charged. However, if the green light shows and the battery isn’t fully charged, this could be a sign of a problem with the battery.

It’s also worth mentioning that you should only use the charger that came with your e-bike. Using a different charger could not only damage the battery, but it may also void the warranty, leaving you without cover in case of a fault.

Caring for Your E-Bike Battery

Lithium batteries are pretty robust, and one of the best things about them is that they don’t suffer from the old “memory effect.” This means you can top them up after every ride without needing to fully discharge them first. In fact, it’s better to avoid fully discharging your battery as it can cause damage to the cells, making the battery unusable. Most e-bikes come with a Battery Management System (BMS) that automatically shuts down the battery when it gets too low - usually around 30 volts for a 36V battery and 42 volts for a 48V battery.

With regular use and proper care, a good quality battery should last several years and handle between 500 to 1,000 charge cycles. However, if your bike sits unused for long stretches of time, you’ll want to charge the battery every couple of months to keep it healthy.

Recognising Battery Issues

If your battery starts taking longer to charge or doesn’t seem to reach full capacity, these could be early signs of wear and tear. Similarly, if your battery has been fully discharged and the BMS has shut it down, it’s important to at least partially charge it within 24 hours to avoid damaging the cells.

Cold weather can also affect battery performance. When temperatures drop below 10°C, you might notice reduced range and power from your e-bike. In these conditions, try to keep your battery warm before setting out and only fit it to the bike just before you’re ready to ride. If you’re storing your bike for a long period, charge the battery to around 70% and give it a top-up every couple of months.

Replacing and Repairing Batteries

Occasionally, a charger may fail before the battery itself. So if you’re having trouble charging, always test the charger first before assuming the battery needs replacing. It’s a lot cheaper to replace a faulty charger than an entire battery!

If your battery gets dropped or knocked, inspect it carefully. A cracked battery case can let water in, which will eventually cause problems. If you notice any damage, get it checked out by a professional. Don’t try to repair it yourself, as this could void your warranty.

Key Signs of a Faulty or Dangerous Battery

In rare cases, e-bike batteries can become fire hazards, but there are some tell-tale signs that will give you early warning:

• Excessive heat: While a battery can get warm during charging, it should never feel dangerously hot.
• Bulging or leaks: A swollen battery or any sign of liquid is a red flag, and you should stop using it immediately.
• Strange noises or smells: Hissing, cracking, or any unusual smell from the battery could be an indication that it’s failing.
• Smoke: If you see smoke coming from the battery, stop everything and follow emergency procedures - evacuate the area and call 999.

General Care and Storage Tips

Keep your battery and charger in a dry place, and avoid leaving them plugged in for long periods after charging is complete. If you ever need to replace the charger, make sure to get one from your e-bike’s manufacturer, as it’ll be matched to your battery and ensure safe, reliable charging. Using a non-official charger might cause issues and, as mentioned, void your warranty.

When cleaning your e-bike, avoid using high-pressure water, as this could force water into the battery compartment. If your battery gets wet, leave it in a warm, dry place for a few days to dry out before using it again.

Conclusion

With proper care, your e-bike battery can last for many years, providing reliable power for all your rides. Stick to the charger that came with your bike, keep an eye out for any signs of damage, and regularly charge your battery to get the most out of it. By following these simple steps, you’ll not only extend your battery’s life but also ensure your rides remain safe and trouble-free.