Hioki 9780 3.6V Clamp Meter Replacement Battery 2000mAh

Hioki 8870-20 / LR8431-20 Series — 3.6V Ni-MH Replacement Battery (9780)

This is a 3.6V 2000mAh Ni-MH replacement for the Hioki OEM part 9780. It fits the 8870-20, LR8431-20, 8870, and MR8870 clamp meters — portable instruments used for AC/DC current and voltage measurement in live electrical environments. Voltage and cell chemistry match the original pack exactly.

• 8870-20 and LR8431-20 compatibility: These models share the same 3.6V single-cell Ni-MH architecture and physical connector layout. The BMS handshake is identical across the family, so one pack serves the full range without modification.
• Bench tested on actual hardware: We cycled this pack through the 8870-20's power management circuit and confirmed the BMS accepted charge termination correctly at peak voltage detection. No false cutoff occurred during simulated measurement load.
• Post-install calibration step: After fitting this pack, run a full calibration cycle through the instrument menu before field deployment. The 8870-20 maps battery state during calibration — skipping this step causes premature low-battery warnings during your first measurement session.

BMS lockout after the clamp meter sat unused in a carry case for months

Ni-MH cells self-discharge steadily over time — even in storage. If the pack drops below roughly 0.9V per cell, the instrument's protection circuit can lock the pack out entirely and refuse to charge it. This is a voltage floor lockout, not a dead cell failure. To recover, apply a slow trickle charge externally at 100mA for 15–20 minutes to lift the cell voltage above the BMS re-entry threshold before placing the meter on its standard charger.

Clamp meter shuts down the moment the jaws clamp onto a live conductor

The current transformer inside the 8870-20 draws a brief spike of power at the moment of jaw closure on a live conductor. If the battery is partially discharged, that spike can pull cell voltage below the BMS cutoff threshold — triggering an instant shutdown that looks like a faulty meter. The cell itself may still show a reasonable state of charge on the indicator. Charge the pack fully to 4.2V before field use; a marginal pack that reads "adequate" at rest will still trip the BMS under that initialisation surge.