About this replacement
Symbol ES400 / ES405 — 3.7V Li-Polymer Replacement Battery (BTRY-ES40EAB00)
This is a 3.7V, 3000mAh Li-Polymer battery for the Symbol ES400 and ES405 mobile barcode scanners. It replaces OEM part numbers BTRY-ES40EAB00, 82-118523-01, and 82-118523-011. The ES400 series is widely used in warehouse pick-and-pack, retail inventory, and logistics scanning environments where scanner uptime is critical.
- ES400 and ES405 compatibility: Both models share the same battery bay dimensions, contact layout, and BMS handshake protocol. The same 3.7V cell and protection circuit works across both units without modification.
- Bench tested on actual hardware: We ran this pack through the ES400's BMS handshake sequence and confirmed the protection circuit communicates correctly with the scanner's charge controller. Capacity was verified at 3000mAh under controlled discharge.
- First-shift preparation: After installing this pack, place the ES400 in its cradle for a full charge cycle before using it in pick-and-pack. Scan trigger inrush current is highest when the cell is near minimum — a pre-charged cell prevents false BMS trips on the first shift.
Cradle showing a charging error on a new pack
A charging error on the cradle dock does not always mean a faulty battery. High contact resistance between the pack's gold contacts and the cradle's charging pins is the most common trigger. Dust, skin oils, or oxidation on either surface can raise resistance enough for the dock's fault detection to flag an error. Wipe the battery contacts and cradle pins with a dry cloth, reseat the pack firmly, and confirm the charging LED changes state within 30 seconds.
Scanner losing wireless connection during rapid scan bursts
The ES400 draws from the same cell to power both the wireless radio and the scan imager simultaneously. During rapid consecutive scans, the combined inrush from the imager trigger and the radio's polling cycle can cause a momentary voltage sag on a partially depleted cell. The BMS interprets this sag as an undervoltage condition and briefly interrupts output, which drops the wireless link. Keeping the pack above 50% charge during high-frequency scanning shifts eliminates this sag — check the battery indicator before starting a burst-scan session.