Battery monitoring system improves military vehicle reliability

June 17, 2014 // By Paul Buckley
The next generation Battery Monitoring System (BMS) from Raytheon is now capable of using sensorless current measurement to provide military vehicle users with more reliable and more accurate State-of-Charge (SOC) and State-of-Health (SOH) information.

The data can be used to help extend the life of batteries, reduce the number of unnecessary battery replacements and give greater confidence on how long engines can remain inactive during Silent Watch.
Raytheon’s BMS also features an integrated Battery Equalizer, for improved on-platform battery availability, and does not require external current shunts which reduces installation and maintenance costs. The BMS also incorporates an operational feature whereby the equipment intelligently reverts to a hibernation mode when the platform is not in use to minimise the platform power drain to 30 mW per Battery Monitoring Unit (BMU).
The improved accuracy is the result of a number of refinements and developments made by Raytheon into battery measurement. Battery voltage measurement is now resolved to 0.25 mV, with an error of ±1% over the range 0 to 16.6 V.
Battery current is measured typically to ±1% or better. In addition, battery impedance measurements can now be resolved to 6.4 μΩ, and battery temperature can be measured to a resolution of ±0.5°C
Neil Glachan, Business Development Executive for Raytheon’s Integrated Power Systems, comments: “Other battery monitoring systems have had problems tracking the battery State-Of-Charge due to issues with complex calibration requirements at set-up, compounded with basic measurement accuracy shortcomings. When in Silent Watch, the crew needs to know battery condition with high confidence to avoid unnecessary engine running. Automatic BMS calibration and accurate current and voltage measurement are key to robust monitoring of the battery State-of-Charge and State-of-Health.”
Raytheon’s next generation BMS will be able to monitor up to eight 12 V batteries – connected in series-parallel – simultaneously and it will interface to other vehicle systems via a MilCAN or J-Std-1939 interface. The BMS will also operate reliably down to 5.5 V.
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