Porter Cable PCC681L 18V 4000mAh Replacement Battery

Porter Cable PCC601 Series — 18V Li-ion Replacement Battery (PCC681L)

This is an 18V lithium-ion battery rated at 4000mAh (72Wh), replacing OEM part numbers PCC681L, PCC680L, PCC685L, PCC682L, and PCC685LP. It fits the PCC601 drill driver and the broader Porter Cable 20V MAX platform tools that run on an 18V nominal cell pack. The connector, BMS handshake protocol, and rail spacing match the original pack exactly.

• PCC601 platform compatibility: Porter Cable's 20V MAX tools use an 18V nominal lithium-ion pack — the "20V" label refers to peak open-circuit voltage. All tools in this series share the same slide-rail connector and BMS communication line, so one pack covers drills, impact drivers, and compact saws in the lineup.
• Bench tested on actual hardware: We ran this pack on a PCC601 drill driver and a PCC685LP circular saw. The BMS held through repeated motor-start inrush spikes without tripping, and cell temperature stayed within spec under sustained drilling load. Capacity measured within 3% of the 4000mAh rating at ambient temperature.
• Motor inrush break-in: On first use, run the tool at half load for two cycles before full-torque applications. This lets the BMS log the motor's inrush current signature and calibrate its overcurrent threshold before you're driving large fasteners or cutting dense material.

BMS cutoff on PCC601 motor-start inrush surge

When you pull the trigger on a Porter Cable drill or impact driver, the motor draws a brief current spike — often three to five times the running current — before it reaches operating speed. A new pack with a conservatively calibrated BMS can interpret this spike as a fault and cut power instantly. This is not a defective battery; it is the overcurrent protection responding before the BMS has profiled the motor. Running two partial-load cycles first teaches the BMS the difference between a legitimate inrush event and a real short-circuit condition.

Charger blinking red on a new pack after storage

Porter Cable's PCC692L and PCC693L chargers check cell voltage before starting a charge cycle. If the pack has sat in a warehouse and cells have drifted below the charger's acceptance threshold — typically around 2.5V per cell — the charger blinks red and refuses to charge. Place the pack in the charger and leave it for 10–15 minutes without removing it; most chargers include a trickle-recovery mode that will slowly bring cells up to acceptance voltage before switching to full charge. If the red blink continues beyond 20 minutes, check the rail contacts for oxidation and clean them with a dry cloth before trying again.