Typhoon MyGuide 3500 Mobile Replacement Battery 3.7V 1300mAh

Typhoon MyGuide 3500 Mobile / 6500 Series — 3.7V Li-ion Replacement Battery

This 3.7V, 1300mAh Li-ion battery replaces the original cell in the Typhoon MyGuide 3500 mobile, 3500 Lidl, Guide, and 6500 series portable GPS navigation units. These are handheld PDA-class devices from the mid-2000s. Dimensions are 50.00 × 35.90 × 8.50mm — measure your original before ordering if you are unsure of your exact variant.

• MyGuide 3500 and 6500 platform fit: These models share the same battery bay dimensions, connector orientation, and 3.7V single-cell architecture. One replacement cell covers the full range listed above without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a PDA-class test rig. The protection circuit handled over-charge cutoff and low-voltage lockout correctly at both ends of the curve.
• RAM state before you pull the battery: Sync all open files and application data to a host PC before removing the old cell. The MyGuide stores active map state and user waypoints in RAM powered directly by the main battery. A full power loss — even for a few seconds — clears that data permanently.

Why the MyGuide 3500 won't boot after a new battery is fitted

A replacement cell ships with a partial charge — typically 40–60% state of charge for transport safety. The MyGuide boot sequence draws a short high-current spike to initialise the display and GPS module. If the cell voltage is below roughly 3.5V at power-on, the protection circuit trips and the unit appears dead. Charge the new battery fully before attempting the first boot — connect to the OEM charger or a USB source and leave it until the charge indicator clears.

MyGuide 3500 reporting shorter battery life after a replacement swap

A new Li-ion cell sometimes under-performs for the first few cycles because the electrodes have not yet reached full ion mobility. Run two or three full charge-to-discharge cycles with the GPS active before judging capacity. Also check that the device is not left in map-rendering mode with the backlight at maximum — the LCD backlight is the single largest current draw on this platform and cuts usable charge significantly. After the break-in cycles, battery life should stabilise at or near the 1300mAh rated capacity.