[WBFAir]

Well I don't know about Li-Ion batteries for sure but I dealt with several other types such as Li-Po and Ni-Cad batteries in my RC-Helicopter hobby where people are dealing with $100 to $400 batteries powering thousand dollar machines so they don't mess around with pushing things and I can tell you that the general consensus is, when charging the batteries that they will charge fine till full an then start rising in temp and thats when you are supposed to disconnect them and if you don't this is a really good way to start causing some damage to the battery.

Again I don't know about these units but if there getting warm and even decently warm that you would notice

...this is not good.