The health of an RC lipo battery is closely related to its performance and safety. Therefore, knowing how to check its health status with the right tools is crucial. Key health indicators include the battery’s actual capacity, internal resistance, the gap between cells, and C-rate. Additionally, some experienced users can roughly assess the battery’s health through their own judgment. In the following sections, I will comprehensively explain some simple methods to help you make informed decisions.
In the RC hobby, we have several tools available for checking battery health, including smart chargers, dischargers, and checkers. Among these, smart chargers are the most commonly used. So, let’s start by understanding how a smart charger can assess the health of an RC lipo battery.
A smart charger displays various data during the charging process, such as the charged capacity, the voltage of each cell, internal resistance, and charging time. Here’s what you should know:
RC Smart Charger
Capacity
The actual capacity of the battery is the amount of charge from 0 volts (3.3V per cell) to full charge (4.2V per cell).
Voltage Gap Between Cells
A small voltage gap between cells indicates good cell quality. A gap within 10mV is excellent, within 50mV is good, and beyond 300mV is unacceptable.
Internal Resistance
Lower internal resistance is better, though it varies with battery size. Smaller batteries have higher internal resistance. Typically, for a 5000mAh battery, an internal resistance under 2 milliohms is excellent, under 5 milliohms is good, and beyond 10 milliohms is poor.
Charging Time
Under the same charging conditions, longer charging times indicate a larger voltage gap between cells, requiring more time for the charger to balance them. Generally, a good battery can be charged from 0 to full in 1 hour at a 1C charging rate.
Checkers and Analyzers
We can use a compact and convenient voltage checker to examine the voltage gap between battery cells.
For more detailed health information, we can use a professional analyzer that provides real-time data during charging or discharging, including:
- Voltage gap between cells
- Current
- Capacity
- Power
- Temperature
- Time
Other Methods
Besides using tools, we can also gauge the battery’s health by observing the following signs:
- Damage, deformation, or leakage
- Swelling
- Overheating during operation
- Shorter run time compared to before
- Longer charging time compared to before
- Reduced power output compared to before
If you notice the first or second signs, it is advisable to stop using the battery due to safety concerns. For the third to sixth signs, while the battery’s performance has degraded, it can still be used.
