In this article, we break down the Reference Performance Test (RFT). Learn more about how the RPT helps monitor a battery’s fundamental health markers and makes sense of it.
In battery development and lifecycle management, data is only as good as its context. While continuous monitoring gives you a stream of information, the Reference Performance Test (RPT) provides the “anchor points” necessary to make sense of it.
Think of a battery like an athlete. You can monitor their heart rate during every workout (operational data), but to truly know if they are getting faster or losing stamina, you need a standardized stress test under controlled conditions. That is the RPT.
What is a Reference Performance Test?
An RPT is a highly standardized, periodic procedure used to measure a battery’s fundamental health markers—specifically Capacity and Internal Resistance. Unlike operational data, which is “noisy” due to varying temperatures and load profiles, an RPT is conducted under strict lab conditions (fixed temperature, specific C-rates, and rest periods).
Why the RPT is Essential
1. Decoupling Noise from Degradation
In the field, a battery might show a voltage drop because it’s cold, or because it’s being pushed too hard, or because it is actually dying. By pulling the cell into an RPT environment (typically at a stable 25°C), you remove the environmental variables. This allows you to see the true State of Health (SOH) of the chemistry, separate from the “operational weather.”
How often are you currently “checking in” on your cells with standardized tests
versus relying on live operational telemetry?
2. Calibration of the BMS SOH (State of Health)
Battery Management Systems (BMS) use algorithms to estimate how much energy is left (State of Charge). Over time, these algorithms “drift.”
– Resetting the Baseline: The RPT provides a ground-truth measurement that allows engineers to recalibrate the BMS.
– Accuracy: Without periodic RPTs, the BMS’s estimation of remaining life becomes a guess, which can lead to premature system shutdowns or, worse, safety risks.
3. Identifying Failure Modes Early
An RPT doesn’t just tell you the battery is degrading; it can hint at how. By looking at the change in the voltage curve during a standardized RPT discharge:
– Capacity Loss: Suggests Loss of Lithium Inventory.
– Resistance Spike: Suggests degradation of the electrodes or electrolyte breakdown.
Summary: The Cost of Skipping RPTs
Skipping Reference Performance Tests is like flying a plane without periodically checking your instruments against a known horizon. You might feel like you’re level, but you could be drifting into a stall.
For any serious battery program, the RPT is the only way to turn “raw data” into “actionable intelligence.” It ensures that when you say a battery has 90% health, you aren’t just guessing—you’re measuring.