You won't have a problem as long as you understand the minimum charge times involved. However, you’re rarely charging an "empty" battery. Your only replacing what you last used. The size of the "hole" in the pack is what determines the fill time. A more extreme example is out 1650 TX packs. 90% (or more) of the people who own these are charging them on a traditional 50 or 60mah wall wart charger. Once you get the pack full, overnight will keep it full as long as you haven't deep discharged it. So, 42 hours to charge initially, but after a 4 or 6 hour trip to the flying field, it's not empty and 50mah overnight is plenty good enough to "top" top it off again.

Where these types of myths are started and perpetuated is a fellow buys a new pack. Lets say it's an 1800 Sub C RX pack for a new larger model he just finished. He charges the thing on his stock 50mah wall charger for 14 hours. Overnight always filled the stock factory pack so why wouldn’t it fill this one he thinks. Later he cycles the pack after some use and discovers it only has 600mah or so in it. He charges again overnight, cycles down again. Again it has 600mah in it. He tells his buddies you can't charge large packs on a small charger. He's totally 100% wrong. He just did not understand the concept that a bigger gas tank takes longer to fill. Problem is, the falsehood gets repeated so many times it becomes "fact" in peoples minds. Most people will not take the time to test such advice and presume there good buddy old “Albert” would never guide them wrong.