Alpha Technologies FXM 650, 1100, 2000 UPS - Manual (Page 41)

39 017-230-B4 Rev B
NOTE:
The Battery Runtime Remaining algorithm attempts to calculate the health of the battery to get a more accurate
prediction of the remaining battery runtime. An accurate estimate of the battery health requires that at least one
battery discharge greater than 20% depth of discharge has taken place since the unit was switched on. When
the unit is powered up from an off state, the algorithm assumes that a new battery is connected to the unit. Each
discharge of greater than 20% will result in a new calculation for the relative battery health. This value is then
used in the Battery Runtime Prediction algorithm to compensate for an aging battery. We recommend that the
user set up a periodic (every 6 months) battery test with a depth of discharge of at least 20%.
The Battery Runtime Remaining algorithm relies heavily on the battery voltage to predict the remaining runtime.
This results in a less accurate predicted runtime during periods when the battery voltage is changing rapidly. The
battery voltage typically changes rapidly during the first few minutes of discharge when the unit switches from
charging to discharging while the unit is in the Inverter mode. The battery voltage may also change rapidly during
the last 20% of the discharge time when the battery is almost drained.
In the Battery Configuration table, Temperature Compensation (default 0.0mV/Cell/°C for bulk charger) and
Max Charger Current have the same function as the Standard charging method.
The following three parameters are only available when the Bulk battery charging method is selected:
Parameter 48V 24V
Default Minimum Maximum Default Minimum Maximum
Max Charger Voltage (Vdc) 53.5 52 56 26.8 26 28
Float Charger Voltage (Vdc) 53.5 52 56 26.8 26 28
Low Voltage Warning*(Vdc) 44 44 47 22 22 23
*Low voltage warning value has to be higher than Low Voltage Disconnect and lower than Low Voltage
Reconnect
Low Voltage Disconnect and Low Voltage Reconnect have the same function as the Standard charging
method.
Bulk Charging Method
The Battery maintenance page has two tables: Battery Primary Configuration and Battery Configuration.
In the Battery Primary Configuration table, select Bulk battery charging method.
Figure 23 — UPS Maintenance: Battery, Bulk charging method