Tecdesk Model 5 Compatible Battery 3.7V 1200mAh TD/BAT1000

Tecdesk Model 5 — 3.7V Li-ion Replacement Battery (TD/BAT1000)

This is a 3.7V, 1200mAh (4.44Wh) Li-ion replacement battery for the Tecdesk Model 5 smartphone. It fits the original battery bay directly, using OEM part references TD/BAT1000 and TD/GEN1000. If your Model 5 no longer holds charge or shuts down unexpectedly, this cell restores full operation.

• Tecdesk Model 5 fitment: The Model 5 uses a single-cell 3.7V nominal architecture with a fixed connector pinout. This replacement matches that voltage rail and connector layout, so the charge IC communicates with the cell without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Model 5 platform. The BMS accepted the cell without fault flags, and the charge IC completed a full constant-current/constant-voltage cycle without interruption.
• Fuel gauge recalibration on first use: On first installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes load into an uncalibrated coulomb counter.

Why the Model 5 reports wrong battery percentage after a cell swap

The Model 5 uses a fuel gauge IC that builds a charge model against the original cell's impedance and discharge curve over hundreds of cycles. When a new cell goes in, that stored model no longer matches the physical chemistry it's measuring. The gauge reads state-of-charge against the wrong curve, so it can show 40% and drop to 0% with no warning, or sit at 100% long after the cell has peaked. One full slow-charge cycle — from under 10% to 100% without fast charge — forces the coulomb counter to reset and relearn against the new cell. After that cycle, percentage readings stabilise.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops sharply under high-current load — modem transmit bursts, screen at full brightness, or GPS active simultaneously. A fresh cell with an uncalibrated fuel gauge has no accurate low-voltage floor mapped yet, so the device hits the hardware cutoff without the OS issuing a low-battery warning. The BMS trips to protect the cell once voltage sags below approximately 3.0V under load. Run the recalibration cycle first; if shutdowns continue after that, check the screen brightness and background sync settings to reduce simultaneous peak draw.