Optimum charging for any battery is C/5 where C = Capacity. I am using this charger to charge Ansmann 7.4V 6600 mAh NP-F970 batteries, so the high (H) setting of 1500 mA for a single battery or 800 mA x 2 when used to charge two batteries at the same time is perfectly adequate. So it should take around 4 hours to quickly charge a single battery pack. Any faster would only reduce the charge-recharge lifespan of the cells within each battery. I know people want to charge Li-Ion cells in as short a time span as possible, but this is not good for the longevity of the battery. Charging two batteries can easily be done overnight. The key to prolonged usage of Li-Ion cells is to not let the voltage drop too low, thus when capacity drops to around 30 percent or so, then they should be recharged. Even better is to recharge them when capacity is at 50 percent, plus will take less time to reach full again too.
I have not tested the USB-A charging port or the in-car portable lighter plug and cable, but having the option to recharge batteries on the move is an additional benefit.
So far, I am very pleased with this device, especially as the NP-F plates secure easily, the display is bright and clear, and overall the charger unit appears solid and well-constructed.
If you want more speed in charging, then buy additional chargers!