Fromm P326 Replacement Battery 18V 4000mAh Li-ion

Fromm P326 Series — 18V Li-ion Replacement Battery (N5-4349)

This is an 18V 4000mAh Li-ion battery for the Fromm P326, P327, P328, and P329 cordless strapping tools. It replaces OEM part numbers N5-4349 and N5-4349-A. The pack slots directly into the tool handle and powers both the tensioning motor and the welding or sealing cycle.

• P326–P329 platform fit: These four models share the same 18V battery rail, connector pinout, and BMS handshake protocol. One pack covers the full range without adapter or firmware difference.
• Bench tested on actual hardware: We ran this pack through full tensioning cycles on a P326 unit. The BMS held stable through repeated peak-draw events at maximum tension setting, and the charger handshake completed without fault codes.
• Cold warehouse use: If the tool sits in a loading dock or freezer corridor below 10°C, bring the battery above that threshold before strapping. The tensioning motor pulls a sharp current spike at max tension — cold cells trigger the BMS overcurrent cutoff before the cycle completes.

BMS cutoff during the tensioning cycle on a new pack

The tensioning motor on the P326 series draws a short, high-current spike when it reaches maximum strap tension. A new or recently stored battery with partially depleted cells can hit the BMS overcurrent threshold at exactly that point, cutting power mid-cycle. This is not a faulty pack — it is the protection circuit doing its job on a cell that has not yet reached full charge. Charge the pack to 100% on the Fromm charger before first use and the spike stays within the BMS window.

Charger shows a fault light on a pack that has been in storage

Li-ion cells that sit unused for several months can drop below the charger's minimum acceptance voltage — typically around 2.5V per cell. The Fromm charger reads this as a fault and refuses to initiate a charge cycle. Some chargers include a recovery or wake-up mode; check the charger LED sequence in the manual for a slow-flash pattern that indicates recovery mode rather than a hard fault. If the charger has no recovery mode, a compatible Li-ion charger with a boost or pre-charge function can bring the cells back above 3.0V per cell, after which the Fromm charger will accept the pack normally.