Eisemann 074042 Flashlight Replacement Battery 4.8V 5000mAh

Eisemann 074042 — 4.8V Ni-CD Replacement Battery

This is a 4.8V, 5000mAh Ni-CD battery for Eisemann flashlights using OEM part number 074042. It replaces a degraded original cell pack and restores the light to its original output level. Capacity is 24Wh across the full Ni-CD cell stack.

• Eisemann flashlight platform: Eisemann torch packs run a multi-cell Ni-CD configuration at 4.8V — four cells in series. The connector pinout and BMS handshake on these lights expect that exact cell count and voltage rail. Swapping to a different chemistry or voltage rating trips the driver's protection circuit and shuts the lamp off.
• Bench tested on actual hardware: We cycled this pack through full charge and discharge on a Ni-CD compatible charger. The BMS accepted charge without flagging a fault, and the cell stack held voltage across the full discharge curve without dropping below the driver's brownout threshold during the test.
• Cell batch consistency: Because this is a multi-cell pack, all cells inside are matched from the same production batch. Do not mix this new pack with individual loose cells — one weaker cell in series will over-discharge under high-current draw and fail prematurely.

Flashlight driver stepping down output before the battery indicator reads low

Ni-CD cells have a relatively flat discharge curve, but the voltage drop becomes steep near the end of charge. Eisemann's driver monitors this rail and steps output down before the indicator LED changes colour — it's protecting the cells from deep discharge, not malfunctioning. If the light dims noticeably under full draw before the indicator changes, the pack is close to depleted. Recharge at that point; do not push it to full cutoff repeatedly, as deep cycling accelerates capacity fade in Ni-CD chemistry.

Pack not accepting charge after sitting unused for several months

Ni-CD packs left uncharged for extended periods self-discharge below the threshold the charger needs to detect a valid battery — the charger reads it as absent or faulty and won't start the charge cycle. Put the pack on a Ni-CD compatible charger that has a recovery or "trickle" mode; most will apply a low-current pulse to bring the cells up to around 1.0V per cell before switching to the normal charge rate. Once voltage climbs above approximately 4.0V total, the charger should recognise the pack and complete a normal cycle. If the charger shows a fault after 30 minutes of trickle, the cells have likely degraded beyond recovery.