Peaktech 3440 Multimeter Replacement Battery 7.4V 1200mAh

Peaktech 3440 / P3340 Multimeter — 7.4V Li-ion Replacement Battery (PT603450-2S)

This is a 7.4V 1200mAh Li-ion replacement battery for the Peaktech 3440 and P3340 digital multimeters. It slots into the battery compartment using the same connector and cell format as the original PT603450-2S pack. If your meter is shutting down unexpectedly or the original cell no longer holds a charge, this is the direct swap.

• 3440 and P3340 shared platform: Both meters run the same 7.4V two-cell Li-ion rail with an identical connector pinout and BMS handshake protocol — that is why a single pack covers both models without any wiring modification.
• Bench tested on actual hardware: We cycled this pack through the 3440's power-on sequence and active measurement load. The BMS held voltage within spec across probe initialisation and sustained continuity testing without tripping into protection mode.
• Post-install calibration tip: After fitting this pack, run a full calibration cycle through the meter's calibration menu before field use. The 3440 maps battery state during calibration, and skipping this step causes the low-battery indicator to trigger prematurely on the first measurement session.

BMS lockout after the 3440 sat unused in a carry case for months

Li-ion cells self-discharge during storage. If the pack voltage drops below roughly 2.5V per cell — around 5.0V combined — the BMS enters a protective sleep state and blocks charge input entirely. The meter will not power on and the charger shows no activity. To recover, apply a low-current trickle charge at around 5.2–5.5V using a bench supply for 10–15 minutes before reconnecting to the standard charger. Once the BMS sees voltage above the recovery threshold, normal charging resumes.

Readings resetting or dropping out mid-session during sustained logging

When the 3440 logs continuously across multiple input channels, the combined draw from the display, measurement circuitry, and data buffer can cause a brief voltage sag. If the pack is already partially depleted, this sag can dip below the BMS cutoff threshold and reset the active session. The meter restarts and any unsaved log data is lost. Keeping the pack above 50% charge before starting a long logging session prevents this — check the indicator reads at least two bars before you begin.