Charge and Discharge Current Limit Calculation

While many BMS units simply provide an on/off switch to allow and prohibit discharge and charge currents, the Orion BMS carefully calculates the actual maximum amperage limits such that it prevents the application from drawing the battery voltage above or below the voltage limits.

Other BMS systems simply respond to over-voltage or under-voltage conditions by cutting the limits after the fact.  In contrast, the Orion BMS provides the application an accurate view of how much power is available for charge or discharge by actively calculating the values ahead of time.

Pre-calculated current limits are very important in a vehicle application where the main drive computer needs to quickly make decisions based on the power available from the electric system. Failure to have reliable limits can allow the main control computer to draw too much current from the battery, causing the limits to suddenly dive. In order to respect the new limit, the main drive computer would be forced to reduce current, leading to a jerky or possibly dangerous driving experience.

The limit calculations take into account the health of the battery pack, internal resistance, battery temperature, and also enforce the maximum pre-set limits in the programmable battery profile for current draw at various temperatures. Values can be expressed in amps or kilowatts for automotive applications.


Ewert Energy Systems, Inc
120 Easy St. Suite #14
Carol Stream, IL 60188

Phone: (630) 868-3173
Fax: (866) 657-5667

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