Magnum Energy ME-RTR Router - Manual (Page 115)

Page 107
©
2014 Magnum Energy, Inc.
Using a BMK: Operation/Monitoring
8.2 ME-BMK Operation/Monitoring (with the ME-RTR)
This section explains how the ME-BMK (Battery Monitor kit) battery monitor works, and how to
use the ME-RTR to obtain battery bank information. It also covers the various LCD displays that
are related to the battery monitor and the status of the sense module’s LED indicator.
Info: Battery monitor menu items are accessed via the RTR router’s BMK Home screen.
For information on how to access the BMK Home screen refer to the Info in Section 8.1.
8.2.1 How does the ME-BMK Battery Monitor Operate?
The ME-BMK uses a precision resistor known as a shunt to measure current fl ow into and out of
the battery. The shunt provides a small voltage to the BMK sense module that is proportional to
the current fl ow. When the battery current starts fl owing, the sense module measures the amount
of current removed from and returned to the battery. The amount of current (or AHrs) removed or
returned is displayed as the METER: 05D Amp Hours In/Out value. This Amp Hours In/Out number
is compensated by the SETUP: 05A Charging Effi ciency value that accounts for energy loses while
charging, and is one of the factors used to determine the battery’s State Of Charge (SOC).
The battery’s state of charge—which is the best indicator of the condition of the batteries—is
indicated on the METER: 05A BMK SOC display. This display shows that the batteries are fully
charged (i.e., SOC = 100%) once the following three conditions have been met:
1. The charging voltage has stabilized over a period of time (see Figure 8-3).
2. The charging current has decreased to a low % of the AHr capacity—normally less than 2%.
3. The AHrs that were removed from the battery are within 1% of fully being returned.
When the BMK sense module is fi rst connected, the batteries will need to be fully charged (i.e.,
SOC = 100%) at least once to establish a SOC reference point. While this reference point is being
calculated, the METER: 05A BMK SOC display shows “Think’n” to indicate that the SOC reference
point is calculated. After the batteries are fully charged, the display changes from “Think’n” to
“100%” and begins to provide accurate SOC percentage values. After the batteries have reached
100% SOC and have discharged ≥ 0.5% of the battery capacity setting, the charge effi ciency value
is recalculated and the Amp Hours In/Out read-out resets to the recalculated value.
Info: To help maintain the accuracy of the METER: 05A BMK SOC display and keep the
batteries in good condition, they must be charged to 100% occasionally (~ once a week).
Figure 8-3, Ending Battery Voltage Versus Time