How to Safely Parallel Charge LiPo Batteries: Best Practices and Risks
While it is tempting to parallel charge LiPo batteries for convenience, it comes with significant risks. Parallel charging, which involves connecting multiple batteries in parallel to charge them simultaneously, can cause high currents to flow. This risk is especially pronounced when the batteries have different states of charge. In this article, we will explore the reasons why parallel charging carries risks, discuss the dangers involved, and provide guidelines for safe parallel charging practices.
The Risks of Parallel Charging LiPo Batteries
When you connect two LiPo batteries with different states of charge in parallel, high currents can flow for a short period. The battery with the higher state of charge will likely handle these high currents relatively well, but the battery with the lower state of charge will be charged at a rate far beyond its optimum. This can lead to premature battery failure, significantly reducing the lifespan of your LiPos. In the worst-case scenario, it can cause rapid overheating and even result in fires due to thermal runaway.
Why Not to Parallel Charge Large LiPo Batteries
People might parallel charge small LiPos, typically 1S cells with capacities less than 1000 mAh, due to the lower risks involved. Small batteries are generally cheaper, so the cost of occasional damage is relatively minor. However, for larger LiPos, such as 4S or 6S configurations, the risks are too high.
Practical Guidelines for Parallel Charging
Instead of parallel charging, the easiest and safest method is to use a board specifically designed for parallel charging. Before connecting the batteries, ensure that the voltage on the cells does not differ by more than 0.1 volts. If there is any doubt, it is best to not parallel charge at all and use a single-cell charger, which are relatively inexpensive.
Conclusion
While parallel charging LiPo batteries might save time, it comes with significant risks. It is crucial to ensure that the batteries have a similar state of charge before parallel charging. For most users, it is best to avoid parallel charging altogether and use dedicated parallel charging boards or individual chargers. Always prioritize the safety and longevity of your LiPo batteries to avoid potential accidents and costly repairs.