Batteries used in medical devices don’t always perform as expected, but Abbott Laboratories has issued an advisory to users of its Freestyle glucose monitoring systems in connection with overheating of the batteries used in the device’s readers, a problem the company said is not related to the batteries themselves. Abbott Park, Ill.-based Abbott has received reports of battery swelling and overheating in the reader unit, but advised users that use of non-Abbott charging cables seems to drive the risk of such episodes, urging users to stick with the USB charging cables that came with the readers.