because it makes sense that it's safer(er) to charge batteries in 70*s-80*s air than at 90*s-100*+...
The event I was talking about, the battery wasn't hot when I plugged it in (so it did start charging) but it stopped charging before fully charged because it did get hot enough for the safety to kick in IE un-safe...
Why would it be more safe when the ambient temp is lower? You only mention that the batteries stopped charging because they got hot when the ambient temps were higher. In that they stopped charging did not make them any less safe.