I haven’t used any of my Hitec dual chargers on DC yet, only AC. Both chargers consistently charge a pair of H batteries, and even larger batteries at a 1C rate in between 00:43 to 01:05. Cell voltages usually start out between 3.7 to 3.94v/cell.
You cannot “fast charge” a lipo battery. Attempting to do do is dangerous, reduces the final state of charge due to excessive heat generation, and reduces the battery lifespan. Never remove a depleted battery from the aircraft to immediately recharge it. That also damages a battery due to excessive heat. Let a used battery cool for at least 30 minutes before recharging. Take the time to review the battery information contained in the linked article previously provided. Your questions indicate your understanding of lipos is short of where it needs to be and the linked article will assist expanding that knowledge and help prevent burning down your car or home charging lipo batteries.