About this replacement
Hypercom M4230 / T4230 Series — 7.4V Li-ion Replacement Battery (400037-001)
This 7.4V 1800mAh Li-ion battery replaces OEM part 400037-001 and 400037-002 in Hypercom portable payment terminals. It fits the M4230, T4230, T4240, and T4220 EFT terminals — the compact handheld units used for tableside and on-site card processing. Voltage and cell dimensions match the original factory spec.
- M4230 / T4230 / T4240 / T4220 EFT platform fit: These four models share the same battery bay geometry, 7.4V nominal rail, and BMS handshake protocol. One replacement battery covers the entire family without any adapter or connector modification.
- Bench tested on actual hardware: We cycled this cell through charge and full discharge on the T4230 platform. The BMS accepted the cell without a fault flag, the charge IC reached top-off correctly, and the terminal held through a full transaction sequence including receipt print and wireless comms.
- First deployment on the terminal floor: After installing the battery, run one complete transaction cycle — including a receipt print — before going live. The M4230's charge indicator maps capacity during normal operation and needs at least one full power cycle to display an accurate charge level.
Why the M4230 reboots mid-transaction after a battery swap
The receipt printer motor draws a short but sharp current spike the moment it fires. On a new battery that hasn't completed its first full charge-discharge cycle, the BMS can read that spike as an overcurrent event and trip the output. The terminal loses power for a fraction of a second — just long enough to trigger a reboot. Run the terminal through two or three complete transaction cycles, including receipt prints, after the first full charge. Once the BMS has mapped the cell's internal resistance, those spikes fall within the expected window and the trip threshold is no longer breached.
Terminal won't power on after sitting unused in a drawer
Li-ion cells self-discharge slowly over time. A terminal left unused for several months can drop below 2.5V per cell — the threshold where most BMS circuits lock the output to prevent damage. The terminal appears completely dead and won't respond to the power button. Connect the terminal to its dock charger and leave it for at least 90 minutes without pressing anything. Most charge ICs include a trickle-charge recovery mode that brings the cell back above 3.0V per cell, at which point the BMS releases the lock and normal charging resumes.