ViKLi E05 V2015 Replacement Battery 3.7V 400mAh Li-Polymer

ViKLi E05 V2015 — 3.7V Li-Polymer Replacement Battery (V2015-E05)

This 3.7V, 400mAh lithium-polymer cell replaces the original battery in the ViKLi E05 V2015 compact flashlight. It matches the OEM part numbers V2015-E05 and PL-762229. The 30.10 x 22.00 x 8.00mm form factor fits the original battery compartment without modification.

• E05 V2015 platform fit: The V2015-E05 and PL-762229 references both point to the same flat lithium-polymer cell used across this flashlight variant. The compact driver circuit in the E05 runs directly off the 3.7V nominal rail, so voltage tolerance at the cell level matters — this cell holds within spec at both full charge and low-voltage cutoff.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the E05 driver board. The BMS cutoff triggered cleanly at the low-voltage threshold, and the cell accepted a full charge without thermal deviation above ambient.
• Li-polymer storage tip for compact torch drivers: If the E05 sits unused for more than two months, store it with the cell partially discharged — around 3.7V to 3.8V. Leaving a small lithium-polymer cell at full charge for extended periods accelerates capacity loss in thin-format cells faster than it does in cylindrical lithium-ion cells.

Flashlight driver stepping down output before the indicator reads low

The E05 driver uses a constant-current circuit that monitors cell voltage in real time. As the lithium-polymer cell drops below roughly 3.5V under load, the driver reduces output current to protect the cell — this appears as visible dimming before any low-battery indicator activates. The indicator threshold is measured at rest voltage, not under load, so the gap between dimming and the indicator can be noticeable. Switching to a lower brightness mode at the first sign of dimming extends usable output and prevents the driver from hitting hard cutoff unexpectedly.

Cell not taking a charge after the flashlight sat unused for several months

Thin lithium-polymer cells self-discharge at a higher rate than cylindrical cells. If the E05 has been stored flat for several months, the cell voltage may have dropped below 3.0V — the threshold where most standard chargers refuse to initiate a charge cycle. Some chargers have a recovery or pre-charge mode that applies a low-current trickle until the cell reaches 3.0V, at which point normal charging resumes. Check the cell voltage with a multimeter before concluding the cell is dead — if it reads between 2.5V and 3.0V, a charger with a recovery function can often bring it back.