Pentax DA020F Replacement Battery 7.4V 3400mAh

Pentax DA020F — 7.4V Li-ion Replacement Battery

This is a 7.4V, 3400mAh (25.16Wh) lithium-ion battery for the Pentax DA020F survey instrument. It slots directly into the DA020F battery compartment and powers the unit through image capture, data logging, and field measurement sessions. Voltage and cell count match the original pack specification.

• DA020F platform fit: The DA020F runs a 7.4V two-cell Li-ion architecture. This pack matches that voltage rail and the physical form factor — 70.50 × 38.30 × 20.10mm — so the BMS handshake completes without fault flags at power-on.
• Bench tested on actual hardware: We cycled this pack through cold-start power-on and sustained sensor-load draw. The BMS held voltage above dropout threshold under continuous measurement load and tripped cleanly at the correct low-cell cutoff without hard-locking the instrument.
• First-use calibration step: After installing this pack, run a full calibration cycle through the DA020F instrument menu before taking it into the field. The instrument maps battery state during that sequence — skipping it causes the low-battery indicator to fire early on the first real measurement session.

BMS lockout after the DA020F sat unused in a carry case for months

Li-ion cells self-discharge over storage. If the DA020F sat unused long enough, the pack voltage can drop below the BMS recovery threshold — typically around 2.5V per cell, or 5.0V combined. At that point the BMS enters a protection state and refuses to accept a charge signal from the instrument's internal charger. Connecting the pack to a lab bench supply or a compatible external charger at a low conditioning current (0.1C) for 15–20 minutes usually brings cell voltage back above the recovery floor. Once above approximately 6.0V combined, the BMS re-initialises and normal charging resumes.

DA020F shuts down mid-measurement with no low-battery warning

This is a voltage sag issue, not a capacity issue. Under sustained sensor load — particularly when probe modules draw initialisation current — the pack voltage can momentarily dip below the instrument's minimum operating threshold, triggering an immediate shutdown even though the charge indicator showed healthy. An aged cell with elevated internal resistance sags further under load than at rest, so the resting voltage looks fine but collapses under draw. If this pack shows the same behaviour after cycling, check that cell internal resistance hasn't climbed above roughly 150mΩ per cell — a battery analyser will confirm this in under two minutes.