Amprobe BAT-500 [3474946] Battery Impedance Tester Up to 40V with RS232 PC Interface. The Amprobe BAT-500 Battery Tester quickly and accurately tests batteries without taking the batteries off-line. This Battery Tester features a comparator function with pass/fail indication, and speed testing of batteries up to 500Ah. Amprobe BAT500 Battery Tester, compact and light weight, simultaneously measures battery resistance and voltage up to 40V.