Battery Charging Hub. Features: Spark's Battery Charging Hub is designed to charge up to three Intelligent Flight Batteries in sequence or simultaneously. It optimizes charging based on their power levels and cell voltage. The Charging Hub will limit the charging current to prevent a hazard and prolong battery life when battery temperatures are low. Compatible battery charger: Spark Battery Charger (F1C50 Version 2). Compatible battery model: MB1, 1480mAh, 11.4V.