As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER PARKING AT GATE AN ACRID SMELL DEVELOPED IN THE MAIN CABIN AND FLIGHT DECK. GROUNDED - YES. PERFORMED SMOKE OR FUMES CONDITIONAL INSP IAW B737-800 AMM 05-51-56 AND FOUND THE AUX BATTERY CHARGER INOP. REMOVED AND REPLACED THE AUX BATTERY CHARGER IAW AMM 24-31-31. OPS CHK'D NORMAL.