About this replacement
Fluke Scopemeter 120 Series — 4.8V Ni-MH Replacement Battery (B11483)
This 4.8V, 3000mAh Ni-MH battery pack replaces the OEM B11483 and BP120 units fitted to the Fluke Scopemeter 120 portable oscilloscope and multimeter. It also fits the Fluke 43, 43B Power Quality Analyzers, and Fluke 123 units running firmware below V2.0. Capacity is 14.4Wh — matching the original pack specification from the product data.
- Scopemeter 120 and Fluke 43/43B platform fit: These models share the same 4.8V rail, B11483 connector footprint, and BMS handshake protocol. The pack slots directly into the battery bay and the instrument recognises it without any firmware prompts.
- Bench tested on actual hardware: We cycled this pack through charge and discharge on a Scopemeter 120 chassis. The BMS held cutoff voltage correctly under both scope acquisition load and simultaneous multimeter probe draw without tripping into protection mode.
- Firmware and calibration note for Fluke 123 users: On Fluke 123 units below firmware V2.0, run a full calibration cycle through the instrument menu after installing this pack. The instrument maps battery state during calibration — skipping this step causes premature low-battery warnings during the first measurement session in the field.
Scopemeter 120 shutting down mid-measurement with a charged pack
The Scopemeter 120 draws a current spike when it switches between oscilloscope and multimeter acquisition modes. If the cell impedance is elevated — common in older or deeply discharged Ni-MH packs — voltage momentarily sags below the instrument's low-voltage cutoff threshold. The instrument interprets this sag as a depleted battery and shuts down, even when the pack reads charged at rest. A fresh pack with low internal resistance eliminates this voltage sag and keeps the instrument running through mode switches.
Pack will not charge after sitting unused in carry case for months
Ni-MH cells self-discharge during storage. If the pack has been sitting unused for several months, cell voltage can fall below the charger's detection threshold — the charger sees no minimum voltage response and refuses to initiate a charge cycle. Place the pack in the Fluke BC190 or compatible charger and check whether the charge LED activates within two minutes. If it does not, the BMS needs a recovery pulse — connect and disconnect the charger three times in succession to trigger trickle-charge entry, then allow a full charge cycle to complete before inserting into the instrument.