We bought 4 Firefly batteries at our local Unique store 6 days ago... the girl told me not to charge them until they are red because they will get a memory. I read online that lithium ion batteries will not get a memory. So, today I went to grab 2 more batteries. While there, I asked if they are lithium ion and (the manager this time) she says yes. So I told her that I read online that they will not develop and memory. She said her boss told her they will... So... I'm at a loss. Anyone know for sure?