Signs your e-bike battery may need replacement

When to replace your electric bike battery? Generally speaking, whenever you notice the first worrying signs, such as light overheating, excessively rapid loss of charge, or erratic changes in battery behavior, it might be time to look into E-bike battery replacement. These issues could indicate a declining battery capacity or functionality and should be promptly addressed. In this guide, we cover all E-bike battery replacement signs and explain their significance to help you better understand when to replace your electric bike battery.

Understanding the inner workings of e-bike batteries

Before we tackle the signs that your E-bike battery might need to be replaced, let’s first grasp the essence of the technology behind it all.

Most modern E-bikes use Lithium-ion batteries, which are renowned for their efficiency and overall performance. It is precisely for that reason that Li-ion batteries find so much use across a number of diverse industries, including transportation, manufacturing, power tools, the medical sector and many, many others.

However, though they are produced and designed to provide consistent power, they have their limitations. One of them includes a finite number of charge/discharge cycles.

What does that mean? Essentially, when you charge an E-bike battery, a chemical reaction occurs within the battery cells that causes free ions to move around between the anode and cathode. Over time, though, through what we call general wear and tear, which increases resistance of cells (which limits maximum power you can get and increase heat) and lowers capacity (so battery is depleting faster), also the cells can become imbalanced, meaning they no longer discharge/charge all at the same rate. Since the battery management system bases the device’s charge level on the lowest cell’s state, one cell underperforming can translate to the entire unit becoming less and less efficient. This last effect can be minimized if BMS have balancing circuit. In result battery can underperform or no longer provide acceptable runtime. With cycles also risk of general failure of cell increases.

Common e-bike battery replacement signs

Once the previously described problems start to occur, many other performance-related problems may start to stack and become noticeable. These are, in fact, your typical signs that an e-bike battery replacement is in order.

So, what do you need to be on the lookout for? Take a look at this list:

Loss of range

If you notice that your battery drains after much shorter distances (~30% or more) during rides compared to when it was new on, it’s a clear indicator of battery degradation.

Erratic changes in displayed battery levels

Similarly, if you find that the reading on your display no longer reliably predicts how much further you can go or that it changes rapidly, seemingly at random, it signifies that the cell imbalance problem has become quite significant. Also, if battery shuts down or limits power significantly under load (especially while climbing uphill) it means that you should think about replacement.

Swelling or bulging

Physical symptoms, like swelling, also point toward potential replacement needs, as they can indicate internal battery damage. At that point it’s crucial to look into the matter promptly, as this compromises the safety of the E-bike battery.

Excess heat

If the battery unit heats up a lot during use or during charging, that’s also a grave concern. If battery shuts down due to overheating during charge or discharge it should not be used anymore.

Longer charging time or inability to reach full charge

You should be paying attention to how your battery charges. If you notice that it takes significantly longer to reach full charge or if it’s impossible, that signals a potential problem with the cells and suggests that they may not be operating at optimal capacity.

Preventing battery issues for long-term health

To properly care for your device and avoid all of these E-bike battery replacement signs, you should always use the best practices for optimal battery health:

• Store it in a cool and dry place, if plan to store for longer time (e.g. winter) best to charge to 30-60% or as instructed in manual;
• Avoid letting the battery drain completely, ideally not to let below 20%, if full charge is not needed, charging only to 80-90% (if supported by the charger / battery) also prolong battery lifetime
• Protect it from extreme temperatures, e.g. don’t leave it in heated car, in direct sunlight, in unheated space in winter (especially for below 0 Celcius degrees), especially charging in low / high temperatures is not recommended.
• Use a manufacturer-recommended charger instead of a generic replacement,
• Regularly inspect it for early warning signs

However, when you spot any of the signs we list in the previous section, then, inevitably, it might be time to have your battery replaced.

The takeaway

Understanding when to replace your E-bike battery is crucial to maintaining your safety. If you’re experiencing multiple signs mentioned in this guide, consult with a professional E-bike to obtain a definitive assessment of your battery’s health.