John is correct. And normally the Futaba wall chargers will have the output printed somewhere on them. Somewhere around 75 ma is common, so divide the capacity of the battery, for instance a 750MaH pack, by the output to get the time required to charge it. In this case it would be 750 divided by 75 or ten hours. And what he was saying by not having enough hours in the day to charge them is that if you have a 2100MaH pack, it would take 28 hours to charge so if you fly every day, you will never get it fully charged with a 75ma charger.