I heard you can't take your phone/camera etc in light aircraft because the pressure makes the batteries expand. Is this true? What height would this happen?
Well it is possible unlikely though.
There is a safety factor on all of it though say if they say it will expand at a certain height it possibly wont for 5 times that height but the batteries will only expand if there really cheap and at a very high altitude higher than commercial planes so there is no need to worry.