Dolphin CT40 Replacement Battery 3.8V 4000mAh 318-055-001

Dolphin CT40 / CT40XP — 3.8V Li-ion Replacement Battery (318-055-001)

This 3.8V, 4000mAh (15.2Wh) lithium-ion battery is a direct replacement for the Dolphin CT40 and CT40XP rugged handheld mobile computers. It fits the same battery bay and uses the same connector as the original pack. Swap it in when the original cell no longer holds a charge through a full warehouse shift.

• CT40 and CT40XP compatibility: Both devices share the same 3.8V battery bay, BMS handshake protocol, and physical connector — OEM part numbers 318-055-001, 318-055-002, and CT50-BTSC all cross-reference to this cell configuration.
• Bench tested on actual hardware: We ran this pack through a full charge-discharge cycle on the CT40 platform. The onboard BMS accepted the cell without error flags, and charge termination triggered correctly at capacity.
• First-shift cradle protocol: Place the CT40 in its charging cradle for a complete charge cycle before using it in pick-and-pack. Scan trigger inrush current spikes highest when the cell is near minimum — a fully charged pack prevents false BMS trips on the opening shift.

Cradle showing a charging error on a new pack

The CT40 cradle communicates with the battery over pogo-pin contacts on the base of the device. If those contacts have oxidation or debris from warehouse use, the dock reads an incomplete handshake and throws a charging error — even with a brand-new cell installed. Remove the device from the cradle, wipe the gold contacts on both the battery door and the dock with a dry lint-free cloth, then reseat firmly. If the error clears, the contact surface was the issue, not the battery.

Scanner dropping wireless connection during rapid scan bursts

The CT40 runs its 802.11 radio and the imager simultaneously during high-frequency scan sequences. The combined draw from both subsystems causes a voltage sag on a degraded or low cell — the radio stack loses enough rail voltage to drop its association before the BMS triggers a hard cutoff. If the scanner reconnects immediately after the burst slows, the issue is cell voltage sag rather than a radio fault. Charge the replacement pack fully before the shift and confirm the battery indicator reads 100% before starting high-frequency scan work.