NOVELTY - Determining state of charge of at least one battery used in a battery-powered device involves electrically insulating terminal of battery from contact areas of the battery-powered device with an electrically insulating material; contacting battery terminals with first and second conductors; and determining the state of charge of the battery by attaching a measuring device to the conductors.    USE - For determining the state of charge of at least on battery installed in a battery-powered device, such as asset-tracking device or a locating device comprising a GPS system. It is useful in determining and communicating the location of mobile trailer (all claimed).    ADVANTAGE - The novel method can quickly and easily evaluate the state of charge of batteries without disturbing the surrounding environment of the batteries. The conductors and insulators are easily removed, thus allowing the terminals to come into contact with battery-powered device.    DETAILED DESCRIPTION - Determining the state of charge of at least one battery (11) installed in a battery-powered device without removing battery from the device, or otherwise altering the device, involves:    (1) electrically insulating terminals (20) of the battery from contact areas of the battery-powered device with an electrically insulating material (12);    (2) bringing a positive battery terminal into contact with a first conductor and a negative battery terminal into contact with a second conductor, where the first and second conductors extend from the battery;    (3) determining the state of charge of the battery by attaching a measuring device (24) to the first and second conductors; and    (4) deciding whether the state of charge is acceptable or unacceptable, based on predetermined criteria.    INDEPENDENT CLAIMS are also included for:    (1) An assembly comprising at least one battery, battery-powered device, first electrical conductor in electrical contact with a positive terminal of the battery, and second electrical conductor in electrical contact with a negative terminal of the battery, where the first and second conductors extend from the assembly and allow a measuring device to be placed in electrical contact with the conductors, and where the reading of the measuring device determines the state of charge of the battery; and    (2) A unit for determining and communicating the location of mobile trailer, comprising GPS receiver; communications satellite transceiver; and battery assembly which supplies electrical power to the transceiver, and which comprises battery, first metallic contact area (22), first and second wires (15, 16), ribbon comprising first and second stripes (13), and first and second targets (14) over the respective conductive stripes, where the targets indicate where the probes of measuring device are to be placed.    DESCRIPTION OF DRAWING(S) - The figure shows a battery, conductors, device contact areas, and measuring device.    Battery (11)    Insulating material (12)    Stripes (13)    Targets (14)    Wires (15, 16)    Battery terminals (20)    Contact area (22)    Measuring device (24)