About this replacement
Fatboy Edison the Petit — 3.7V Li-Polymer Replacement Battery (PN704050)
This 3.7V, 1600mAh lithium-polymer cell replaces the original battery in the Fatboy Edison the Petit and LED Table Lamp Edison portable desk lamps. It restores cordless operation after the original cell has degraded through repeated charge cycles. Capacity matches the factory spec at 1600mAh (5.92Wh).
- Edison the Petit and LED Table Lamp Edison fit: Both models share the same battery bay dimensions, 3.7V charging circuit, and PN704050 connector configuration — one cell covers both.
- Bench tested on actual hardware: We cycled this cell through the lamp's charge and discharge stages. The BMS held stable voltage delivery across both low and high brightness modes with no unexpected cutoff.
- First-charge calibration: Charge the lamp fully before first use. The Edison the Petit's fuel gauge reads against a calibrated cell baseline — if the cell ships at storage voltage, the indicator can show low battery immediately after switching to maximum brightness, even with a healthy cell installed.
Why the Edison the Petit dims suddenly on maximum brightness
The LED driver in the Edison the Petit requires a minimum input voltage to sustain full brightness output. Maximum brightness draws significantly more current than warm dim mode — roughly three to four times higher. As the cell voltage drops under that load, the driver steps down output before the battery protection circuit fully trips. This is normal LED driver behaviour, not a fault with the cell itself.
Lamp brightness lower than expected right after fitting a new cell
A new lithium-polymer cell ships at storage voltage — typically around 3.6V — not a full charge of 4.2V. The Edison the Petit's brightness control draws on available cell voltage, so a partially charged cell produces visibly lower output at higher brightness settings. This is not a faulty battery. Connect the lamp to its USB charger and run a full charge cycle before testing brightness. Once the cell reaches 4.2V, full output is restored.