Unitech HT-1853 Replacement Battery 3.7V 1500mAh

Unitech HT-1853 / MS840 Series — 3.7V Li-ion Replacement Battery (113154-O)

This 3.7V, 1500mAh Li-ion battery replaces OEM part 113154-O in Unitech handheld barcode scanners including the HT-1853, MS840, MS840B, and MS840P. It fits the same bay and connector as the factory pack. Capacity figure is taken directly from the product specification — 5.55Wh usable energy per charge cycle.

• HT-1853 and MS840 platform fit: These models share the same 3.7V single-cell architecture, battery bay dimensions, and BMS handshake protocol — so one pack covers the full scanner line without modification or adapter.
• Bench tested on actual hardware: We cycled this pack through repeated scan-trigger and wireless polling loads. The BMS held the correct charge termination voltage and did not trip on simulated inrush spikes during back-to-back barcode reads.
• First-shift charging protocol for the HT-1853: After installing a fresh pack, seat the scanner in its cradle and run a full charge cycle before heading to the pick floor. The scan trigger draws its highest inrush current when the cell is near minimum — a pre-charged cell stops the BMS from tripping on the very first scan burst of the shift.

Cradle showing a charging error on a new pack

Unitech charging cradles read contact resistance before initiating the charge cycle. If the gold-plated contacts on the battery or dock tray have picked up skin oil or warehouse dust, the cradle rejects the pack and throws an error LED. Wipe both the battery contacts and the cradle tray contacts with a dry lint-free cloth, then reseat the scanner firmly until it clicks. The cradle should begin charging within 10 seconds — confirmed at 4.2V termination on our bench unit.

Scanner losing wireless connection during rapid scan bursts

On the MS840 platform, the radio and the scan imager share the same power rail. During a fast burst of consecutive scans, the combined inrush from the imager trigger and the wireless polling cycle can pull the cell voltage below the BMS floor momentarily. The scanner drops its wireless link as the radio resets to protect the cell. If this happens mid-shift, pause scanning for a few seconds to let the cell voltage recover — or return to the cradle and top up to above 3.9V before continuing the picking run.