I-Mate K-Jam Compatible Battery 3.7V 2800mAh WIZA16

I-Mate K-Jam — 3.7V Li-ion 2800mAh Replacement Battery (WIZA16)

This is a 3.7V Li-ion cell rated at 2800mAh (10.36Wh), built to replace the original power cell in the I-Mate K-Jam. The K-Jam is a Windows Mobile smartphone from the mid-2000s that combined phone and PDA functions in a sliding QWERTY form factor. This replacement matches OEM part numbers WIZA16, 35H00062-00M, and 35H00062-03M.

• K-Jam battery compatibility: The K-Jam shares its battery footprint and connector pinout across its OEM part revisions — 35H00062-00M and 35H00062-03M are hardware revisions of the same cell, same dimensions (51.86 × 38.97 × 12.48mm), same 3.7V nominal rail. All three OEM numbers fit the same battery bay without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the K-Jam platform and monitored BMS communication. The protection circuit engaged correctly at low-voltage cutoff, and the charge IC accepted the cell without error flags on the second charge cycle.
• Fuel gauge recalibration after swap: On first use after installing this cell, run one complete discharge down to automatic shutdown, then charge uninterrupted to 100%. This gives the K-Jam's fuel gauge IC a full discharge curve against the new cell before it starts reporting percentages you can trust.

Why the K-Jam shuts down suddenly at 20–30% charge remaining

This happens when the fuel gauge IC's stored discharge curve no longer matches the actual cell's voltage-versus-capacity behaviour. The K-Jam's modem radio draws a sharp current spike during a call or data session. If the cell voltage drops below the BMS cutoff threshold under that load — even momentarily — the phone shuts down to protect the cell, regardless of what percentage the OS was showing. After a full recalibration cycle, the gauge learns where the real voltage cliff sits and the OS percentage tracking tightens up considerably.

K-Jam not powering on after the replacement cell sat in storage

Li-ion cells self-discharge slowly in storage. If this battery sat below 2.5V per cell before installation, the BMS locks out charging as a protection measure and the phone will not respond to the charger or power button. Connect the K-Jam to a charger and leave it undisturbed for 20–30 minutes — the charge IC trickle-charges the cell below the BMS threshold until voltage recovers to roughly 2.9V, at which point normal charging resumes and the device powers on.