wattage is just voltage x amperage so if the x2 does 100w, 100/14.8=~6.8ish amps at 100% efficiency so you are looking more at about 6 amps if you divert all the power in the x2 to 1 channel. The 1-2C rating you see in articles refers to the charge rate and the 75C on the battery is the discharge rate. In general, you should be less concerned about those numbers and more concerned about the quality of the cells. most battery brands buy cells from one of a few different manufacturers, so the cheaper batteries will be the cells that didn't meet the other companies' specifications. The x2 is a bit outdated and underpowered for the price, the x6 seems to be a good charger, just need an ac/dc power supply.