About this replacement
Skil 2587 / 2587-05 — 14.4V Ni-MH Replacement Battery (SB14A)
This is a 14.4V, 2100mAh Ni-MH replacement battery pack carrying OEM part number SB14A. It fits the Skil 2587 and 2587-05 cordless drill/driver. Swap it in when the original pack no longer holds a charge or refuses to accept a charge cycle.
- 2587 and 2587-05 platform fit: Both model variants run the same 14.4V rail and use the same slide-in battery contact geometry and latch mechanism, so one pack covers both. No adapter or modification needed.
- Bench tested on actual hardware: We cycled this pack through repeated trigger-pull events on a 2587 body and monitored the BMS response to inrush current spikes. The overcurrent threshold held without nuisance trips across full discharge cycles.
- Half-load break-in on first use: On the first two cycles, run the drill at medium torque settings — not full torque into hard materials. This lets the BMS log the motor's inrush current signature before it sets its overcurrent protection thresholds. Skipping this step on Ni-MH packs can cause early cutoffs under sudden load.
BMS cutoff on motor-start inrush during hard drilling applications
When you drive a large bit into dense material, the 2587's motor pulls a short but sharp inrush current spike at trigger pull. On a new or cold Ni-MH pack, the BMS may interpret that spike as an overcurrent event and cut power before the motor reaches speed. This is not a faulty pack — it is the protection circuit doing its job with incomplete data. Running two break-in cycles at half load trains the BMS to distinguish normal inrush from a genuine fault. After break-in, full-torque applications should proceed without nuisance trips.
Charger not recognising the new pack after storage
Ni-MH packs lose voltage during storage, and if a cell group drops below the charger's acceptance threshold — typically around 0.9V per cell — the charger refuses to initiate a charge cycle and may blink an error. This does not mean the pack is dead. Place the battery in a warm environment (18–25°C) for 30 minutes, then retry the charger. If the charger still does not engage, a brief trickle charge using a compatible Ni-MH trickle charger can bring cell voltage up to 1.0V per cell, at which point the main charger will recognise the pack and begin a normal cycle.