Finding the Right Balance
Following on from our previous article we’ve established that keeping a lithium battery fully charged isn’t ideal and neither is letting it run completely flat. Even getting close to either extreme fully charged or nearly empty can speed up wear and shorten the battery’s lifespan.
For most lithium batteries, whether in portable devices or electric vehicles the ideal state of charge (SOC) sits between 30% and 70%. Staying within this range offers the best chance of maximising battery life. Many modern devices and EVs are designed to support this kind of battery management. However, it’s not a guaranteed solution on its own.
The challenge is that consistently staying within this range locks out around 60% of the battery’s usable capacity. Over time, this limited usage can lead to another issue: calibration errors.
What Is a Calibration Error?
Battery management systems (BMS) estimate a battery’s state of charge based on known voltage ranges. But if the battery never reaches its maximum SOC, this estimate can drift over time. Without occasional calibration, charging the battery fully, the BMS may report inaccurate readings or allow the battery to operate outside safe limits.
This is why fully charging your battery every now and then is important. While 100% SOC shouldn’t be the daily norm, it plays a role in keeping the system accurate. PowerPlus Energy recommends performing a full charge at least once every 7 to 14 days to keep things on track.
Use the Battery, Don’t Just Preserve It
If you keep your battery between 30% and 70%, and regularly calibrate it, chances are it will maintain excellent health even after a decade. But it’s also important to remember that lithium batteries have a “calendar” life, they age with time, regardless of how carefully they’re used.
This means that if you’ve only used 40% of your battery’s capacity in an attempt to protect it, you might still face degradation once its warranty period ends. In short, you risk underutilising the asset you paid for.
PowerPlus Energy recommends using your Eco4847P between 100% and 20% SOC*. This range provides a practical balance, offering a long lifespan while ensuring you get real value and performance from your investment. For EV users, regularly charging to 80–90% is often a smart compromise for daily driving, with a full 100% charge only needed once a month for calibration.
Key points summarised:
- Charging to 100% too often accelerates degradation.
- Discharging to 0% is even more damaging.
- Keeping the battery between 30% and 70% may extend life but limits usable capacity.
- Occasional full charges are needed for accurate calibration.
- Striking a balance between battery health and practical use is key.
By understanding how lithium batteries work and adjusting how we use them, we can get the best of both worlds, longer battery life and better day-to-day performance.
*For all other PowerPlus Energy rack-mounted batteries check out their specifications here.
