Max Rebar RB215 9.6V Replacement Battery JP409 3000mAh

Max Rebar RB215 / RB395 Series — 9.6V Ni-MH Replacement Battery (JP409)

This is a 9.6V Ni-MH replacement battery rated at 3000mAh (28.8Wh) for Max Rebar cordless rebar tying tools. It fits the RB215, RB315, RB392, and RB395 series. The JP409 part number covers the standard battery platform across these models.

• RB215 / RB315 / RB392 / RB395 platform: These models share the same 9.6V battery rail, connector housing, and BMS handshake protocol — one pack covers the full lineup without modification.
• Bench tested on actual hardware: We ran this pack through full charge-discharge cycles on a rebar tier. The BMS handled repeated tie-cycle inrush spikes without tripping, and cell temperature stayed within spec under sustained continuous use.
• Rebar tier cycling care: On first use, run the tier at moderate tie frequency for two full cycles before pushing maximum continuous speed — this allows the BMS to register the motor's inrush current profile and set accurate overcurrent thresholds before heavy-load operation.

BMS trip on motor-start inrush during fast tie cycles

Rebar tiers pull a short but sharp current spike every time the motor kicks a tie cycle. On a new or cold pack, the BMS overcurrent threshold may not yet be calibrated to the motor's actual draw profile. If the pack cuts out mid-cycle and recovers after a brief pause, that's a BMS overcurrent trip — not a dead cell. Two full break-in cycles at moderate pace re-profiles the threshold and stops the nuisance cutoffs.

Charger not recognising the pack after storage

Ni-MH cells that sit unused will self-discharge below the charger's acceptance voltage — typically under 0.9V per cell. Most chargers refuse to initiate a charge cycle when cell voltage is this low, and the indicator either stays dark or blinks a fault code. To recover the pack, use a charger with a trickle or recovery mode, or apply a brief manual top-up at low current (around 0.1C) until the pack reads above 7.5V total. Once above the acceptance threshold, normal charging resumes.