Energy systems on submersible and aerospace vehicles are the key power unit for the vehicle and are designed to meet the stringent environmental conditions imposed upon these batteries; in particular those which result from acoustically induced random vibration as well as shock. Recently having won a contract to develop battery cell monitoring systems for three prototype submersibles, Curtiss-Wright was contacted by the manufacturer for a compact, lightweight, standalone Ethernet data acquisition & monitoring system. Each submarine will be equipped with two redundant Acra KAM-500 systems to measure the voltage drop and temperature across a battery stack and output the corresponding data over Ethernet as part of the safety system. Four modules are were developed for this project; a high voltage module is needed to monitor AD590 temperature sensors, an analog module that can support common mode voltage of 250V, an analog module that can support a ±200V input, and finally a bespoke utility module will be developed to monitor eight analogue channels, accept commands from a standard KAM-500 programming interface and drive a TTL line in response. As other vehicle systems make the switch to Lithium-ion technology they will also require monitoring solutions.