About this replacement
Ryobi 40V Li-ion 6.0Ah Replacement Battery (OP4026A)
This is a 40V 6000mAh lithium-ion replacement battery for the Ryobi 40V tool platform. It fits the RY40210, RY40200, RY40610, RY40600, and over 76 additional Ryobi 40V cordless tools. Voltage is 40V nominal; capacity is 6000mAh (240Wh) as specified in our product data.
- 40V platform fit — RY40210 and related models: These tools share a common 40V battery rail, connector geometry, and BMS handshake protocol. Any tool in the Ryobi 40V lineup that accepts an OP4026A-type pack will accept this battery without hardware modification.
- Bench tested on actual hardware: We ran this pack through motor-start inrush events on a circular saw and drill. The BMS held overcurrent thresholds correctly on each trigger pull and did not trip during cold-start events at controlled load.
- First-use load conditioning: On first use, run the tool at half load for two cycles before applying full torque. This lets the BMS observe the motor's inrush current draw and set accurate overcurrent protection thresholds before you push maximum load.
BMS cutoff on motor-start inrush surge — RY40210 and circular saw use
When a high-draw tool like a circular saw starts under load, the motor draws a current spike that can be three to five times the running current. If the BMS hasn't profiled that inrush pattern yet — especially with a new or recently stored pack — it may read the spike as a fault and cut power. This is not a defective battery. The BMS is doing exactly what it should. Starting the tool unloaded for the first two cycles allows the BMS to record the inrush signature and relax the overcurrent threshold to the correct operating window.
Tool bogs under load or loses torque mid-cut
This symptom usually points to voltage sag rather than a failing cell. High resistance at the battery rail contacts — caused by debris, corrosion, or a worn connector — drops the voltage under load before the cells themselves are depleted. Remove the pack, inspect both the battery and tool terminals for oxidation or carbon buildup, and clean with a dry brush or isopropyl alcohol. If the pack reads above 36V at rest but drops sharply below 32V under load, the contact interface is the first place to check before assuming the cells are at fault.