About this replacement
Ryobi ZRP813 Series — 18V Li-ion Replacement Battery (P104)
This is an 18V 3000mAh Li-ion battery that replaces the Ryobi P104 and a wide range of compatible OEM part numbers including P102, P103, P107, P108, and BPL1820. It fits the Ryobi ZRP813 compact drill-driver and over 150 additional 18V ONE+ platform tools. Voltage and connector are matched to the original Ryobi 18V ONE+ interface.
- Ryobi 18V ONE+ platform fit: All models in this family share the same 18V rail, physical slide-in connector, and BMS communication protocol. One battery pack works across the entire ONE+ range without adapters or rewiring.
- Bench tested on actual hardware: We ran this pack on a ZRP813 drill-driver through repeated trigger cycles including full-torque fastening runs. The BMS held stable across high-inrush start events and did not trip under normal clutch-load sequences. Cell voltage after discharge settled consistently above 15V at rest.
- First-use conditioning on the ZRP813: On first use, run the drill at half load for two cycles before applying maximum torque. This lets the BMS profile the motor's inrush current draw and set overcurrent thresholds before you push into full-speed fastening or driving tasks.
BMS cutoff on ZRP813 motor-start inrush surge
When you pull the trigger on a drill-driver, the motor draws a spike of current before it reaches running speed — this is inrush current. On a new or recently stored pack, the BMS overcurrent threshold may not yet reflect the ZRP813's specific motor signature. If the BMS reads that spike as a fault, it cuts power before the motor finishes starting. Running two break-in cycles at half load lets the BMS log the inrush profile and adjust its trip threshold accordingly.
Charger showing red and refusing to accept a new pack from storage
If the pack has sat unused for several months, individual cell voltages can drop below the charger's minimum acceptance threshold — typically around 2.5V per cell on 18V Li-ion packs. The charger reads this as a fault and blinks red rather than starting a charge cycle. To recover the pack, place it in the charger and leave it connected for 15–20 minutes — most Ryobi chargers include a trickle pre-charge mode that slowly raises cell voltage until the main charge cycle can begin. If the charger still does not progress after 30 minutes, check that each cell group is reading at least 2.5V before attempting further recovery.