Emporia BTY26155 Elson EL510 Replacement Battery 3.7V 500mAh

Emporia Elson EL510 — 3.7V Li-ion Replacement Battery (BTY26155)

This is a 3.7V Li-ion cell rated at 500mAh (1.85Wh), built to the same electrical spec as the original BTY26155. It fits the Emporia Elson EL510 mobile phone. If your EL510 won't hold a charge or dies unexpectedly under normal use, this is the direct swap.

• Elson EL510 fit: The EL510 uses a compact 39.53 x 40.80 x 3.86mm cell with a low 500mAh draw profile. The BMS on this handset expects a specific voltage curve — a mismatched cell causes early cutoff or erratic percentage readings. This replacement matches the discharge profile the charge IC is calibrated against.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the bench. The BMS accepted the cell without triggering a fault, charge current tapered correctly at end-of-charge, and voltage held above the low-battery cutoff threshold under screen and modem load.
• Fuel gauge recalibration after swap: On first use after installation, disable fast charging if available and run one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's actual discharge curve before making percentage estimates — skipping this step causes the OS to report incorrect battery levels for the first several cycles.

Why the EL510 reports wrong battery percentage after a cell swap

The EL510's fuel gauge IC stores a learned discharge curve from the original cell. When you install a replacement, that stored model no longer matches the new cell's actual voltage-to-capacity relationship. The IC reads voltage and maps it to a percentage using old data, so 40% on screen may reflect a cell that's actually close to cutoff. One full discharge down to automatic shutdown, followed by a full uninterrupted charge, forces the IC to relearn the curve. After that cycle, percentage reporting stabilises.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops below the BMS protection threshold under load — typically during a screen-on spike or a background data burst — even though the displayed percentage still shows capacity remaining. The fuel gauge IC hasn't yet mapped the new cell's voltage cliff accurately, so it doesn't warn the OS in time. The fix is the same recalibration cycle: run the phone down to auto-shutdown, charge fully to 4.2V without interruption, and repeat once more if shutdowns persist. After two full cycles, the IC's low-voltage prediction aligns with the replacement cell's actual behaviour.