Yakumo Delta 300 Replacement Battery 3.7V 1300mAh

Yakumo Delta 300 / 300GPS / GPS 2L — 3.7V Li-ion Replacement Battery

This 3.7V 1300mAh Li-ion cell replaces the original battery in the Yakumo Delta 300, Delta 300GPS, and Delta GPS 2L handheld PDAs. These are early-2000s pocket computers running Windows Mobile, used for contacts, calendars, and document access on the go. Fit, voltage, and connector match the original — no modification needed.

• Delta 300 series compatibility: All three variants — Delta 300, 300GPS, and GPS 2L — share the same battery bay dimensions and 3.7V supply rail. The GPS 2L adds an active GPS receiver, which draws more current than the base model, but the battery interface is identical across the series.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Delta 300 platform. The BMS accepted the charge profile without fault flags, and the device held stable voltage through the full discharge curve without unexpected shutdowns.
• RAM and data state before swap: Sync all open data to your host PC before removing the battery. The Delta 300 stores active application state and unsaved records in SRAM powered directly by the main battery. Pulling the cell without a full sync will wipe anything not committed to flash storage.

Why the Delta 300 loses data every time the battery is changed

The Delta 300 uses SRAM for working memory — contacts, calendar entries, and open files live there while the device is running. SRAM needs continuous power to hold its state. The moment the battery is removed, that memory clears. Some units include a small backup capacitor that buys a few seconds, but it is not reliable enough to cover a full battery swap. Always sync to ActiveSync or a memory card before pulling the cell.

Delta 300 stuck on the boot screen after fitting a new battery

A fresh replacement cell ships at a partial state of charge — often below the minimum voltage the bootloader needs to complete its POST sequence. If the device stalls on the Yakumo splash screen or loops through the boot animation, low cell voltage is the most likely cause. Connect the charger and leave the unit plugged in for at least 30 minutes before attempting to power on again. Once the cell reaches approximately 3.6V, the boot sequence will complete normally.