About this replacement
Samsung Series 5 ChromeBook — 7.4V Li-Polymer Replacement Battery (AA-PLPN4AN)
This 7.4V Li-Polymer battery replaces the OEM cell in the Samsung Series 5 ChromeBook, Series 5 535U3C, XE500C21-A04US, and XE500C21-H04US. It carries 8200mAh (60.68Wh) — the same rated capacity as the original. It fits the existing battery bay and connector without modification.
- Series 5 ChromeBook platform fit: The XE500C21 and 535U3C share the same battery bay dimensions, connector pinout, and BMS communication protocol — that is why a single cell covers this range. The AA-PLPN4AN and AA-PLPN6AN designations reference the same physical pack with minor OEM revision codes.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on a Series 5 ChromeBook. The BMS handshake completed without error codes, charge current tapered correctly at 100%, and the protection circuit triggered cleanly at the low-voltage cutoff threshold.
- Post-install calibration on ChromeOS: After fitting this battery, let the ChromeBook discharge fully until it hibernates, then charge it uninterrupted to 100% without powering on mid-cycle. ChromeOS uses this first full cycle to recalibrate the fuel gauge IC against the new cell's actual capacity curve.
Why ChromeOS reports poor battery health immediately after a cell swap
The ChromeBook's embedded controller reads health data from EEPROM registers on the battery pack. When a new cell is fitted, those registers hold factory default values that do not match the old cell's learned discharge history. ChromeOS interprets the mismatch as a degraded or unknown battery. Running one full discharge-to-hibernate cycle followed by an uninterrupted charge to 100% forces the embedded controller to rewrite the EEPROM learn data against the new cell. After that single calibration cycle, the health indicator updates correctly.
Fuel gauge jumping erratically during the first few charge cycles
The fuel gauge IC inside the ChromeBook calculates state-of-charge by tracking cumulative current in and out of the cell — a method called coulomb counting. With a new cell installed, the IC has no reference baseline, so percentage readings swing 10–20% in either direction under load. This is not a fault with the replacement battery. Two to three full discharge-and-charge cycles give the fuel gauge IC enough data to build an accurate model of the new cell's voltage-to-capacity curve. After the third full cycle, readings typically stabilise within ±3% at the 3.7V nominal midpoint.