Abstract: A preferred thermal control system for a battery stack includes a flexible, thermally insulating, and electrically non-conductive cover supported by a frame to substantially thermally isolate a battery stack from other equipment in a telecommunication shelter. The cover is preferably arranged or cut for placement over existing battery connections so the batteries remain electrically connected to other equipment when the cover is installed on the frame. Cuts in the cover are preferably sealed using an adhesive tape. A heat transfer device is supported by the frame and provides thermal cooling to the battery stack while exhausting heat generated by the batteries from the battery stack enclosure into the interior of the telecommunication shelter. Both the frame and the flexible cover may be adjustable to fit over battery stacks of various sizes.