Manuel succinct, and not in French, English and Chinese only. Basically, each location is autonomous, but if you load 2 batteries at a time, the current is only 0.5A per location. Above each location: 3 LEDs. If after the test of the battery pack (test type and its good condition) 3 LEDs blink together, is that the battery is good to throw away. If only one LED flashes: it symbolizes the state of charge (low, medium, almost ready). If all 3 LEDs are fixed: it is loaded.
Practical: the power cable to cigarette lighter, in addition to taking 110 / 220v.