OutBack Power FLEXmax 100 User Manual

Installation
900-0209-01-00 Rev A 21
Battery Sense Terminals
The remote Battery Sense terminals are used for accurate voltage monitoring. These terminals connect
directly to the batteries. Using the controller’s main battery cables for voltage sensing is less accurate.
This is due to voltage rise caused by charging currents on the battery conductors.
Aux terminals 7 and 8 are the – and + terminals for the Battery Sense function. These terminals are
colored black (–) and red (+) for easy reference. A twisted-pair cable is recommended. (See page 19 for
wire sizes.)
IMPORTANT:
The MATE3s system display shows the overall system voltage as measured at the battery
terminals of various devices. (See Figure 26 on page 35.) This voltage is used for generator
starting and other functions.
 If no other devices are present, it will show the reading of the FLEXmax 100. Unless:
 If OutBack inverters are present, the inverter voltage replaces the FLEXmax 100 as the
system voltage reading. Unless:
 If the FLEXmax 100 Battery Sense terminals are in use, this reading replaces the inverter
or the regular charge controller readings as the system voltage. Unless:
 The FLEXnet DC Battery Monitor is the highest priority and will replace the Battery Sense
reading as the system voltage.
The Battery Sense reading is still shown on the Charge Controller screen. (See Figure 27 on
page 36.) This reading is still used to adjust the FLEXmax 100 charging.
This function operates automatically when it detects a voltage within 2 volts of the battery voltage reading
at the charge controller’s main terminals. If the reading varies by more than 2 volts, the Battery Sense
function is disabled. The assumption is that the terminals are not connected. (If the terminals are
connected, there may be a wiring problem.)
The Battery Sense function has several advantages apart from accurate battery readings.

The more accurate charging may increase battery life.

A single set of readings can be used by multiple FLEXmax 100 controllers.

Conflict between controllers due to differing readings is eliminated.

The need for calibration is eliminated. If Battery Sense is not in use, the user can calibrate the battery meter
at the charge controller’s main terminals. See page 50 and the system display literature for more information.
(If Battery Sense is in use, calibration changes are not needed and will have no effect.)
Figure 13 Battery Voltage Sensing
NOTE: Overcurrent protection
is not shown. Recommended
protection for sense conductors is:

Fast-acting device

80 Vdc or greater

1 A or smaller

Cold resistance 10 ohms
or less
PV+
P
V
–
BAT
–
BAT+
DC TERMINALS

OutBack Power FLEXmax 100 Specifications

General

Brand	OutBack Power
Model	FLEXmax 100
Category	Controller
Language	English