5.2.2 Connecting a Battery to the
DXM Modbus Slave
When attaching a battery to the DXM Modbus Slave as a backup battery or as a solar battery, verify the charging algorithm
is set properly. The factory default setting for the battery charging algorithm assumes you are using 12 to 30 V dc to
recharge the battery.
The charging algorithm is designed to work with a sealed lead acid (SLA) battery only.
• When using 12 to 30 V dc, connect the 12 to 30 V dc + to pin 2 and connect the ground to pin 3.
• When using main dc power with a back up battery (default configuration), connect the incoming main power pin 2
(+) and to pin 3 (-). Connect the 12 V sealed lead acid battery to pin 4 (+) and pin 5 (-). The incoming main power
must be 15 to 30 V dc to charge the battery.
• When using a solar panel, connect the solar panel output to pin 2 and connect the ground to pin 3. Connect the 12
V dc SLA battery to pin 4 (+) and pin 5 (-). To change the charging algorithm, refer to
Supplying Power from a Solar
Panel
on page 10.
The battery charging algorithm defaults to a battery backup configuration. To charge the battery from a solar panel, change
the battery charging algorithm.
1. From the DXM Modbus Slave LCD menu navigate to Setting Config > I/O Board > Charger.
2. Select Solar for solar panel configurations or DC for battery backup configurations.
Modbus Slave ID
Modbus Register
Description
11 *
6071
Battery backup charging algorithm.
0 = Battery is recharged from a solar panel
1 = Battery is recharged from 12 to 30 V dc (default)
* The Modbus Slave ID for the base board is set at the factory and may be changed using the base board DIP switch
settings.
5.3 Working with Solar Power
A reliable solar system requires careful planning and monitoring to size the components correctly. The recommendations
provided are for the DXM Modbus Slave system as an autonomous system.
Adding extra components increases the power requirements and likely requires increasing the solar system components.
Depending upon the geographical location, the size of the solar panel and battery may vary.
5.3.1 Setting the
DXM Modbus Slave
for Solar Power
By default, the DXM Modbus Slave is set from the factory to charge a backup battery from a line power source. Use the
LCD menu on the front of the DXM Modbus Slave to change the charging algorithm to solar power.
Go to System Config > I/O Board > Charger. Use the up/down arrows to select Solar.
For DXM devices without an LCD, adjust the I/O board Modbus register 6071. Set the register to 0 to select battery
charging from a solar panel, and set to 1 to select battery charging from incoming 12 to 30 V dc supply.
Here are a few DXM configuration tips to help minimize the power consumption (may not apply to all models).
• If Ethernet is not being used, save up to 25% of the consumed power by disabling Ethernet. Set DIP switch 1 to the
ON position on the processor board then reboot.
• Instead of powering external devices all the time, take advantage of the switched power mechanisms to turn off
devices when possible.
• Minimize the number of cellular transactions and the amount of data pushed across the cellular modem.
5.3.2 Solar Components
The components of a solar system include the battery and the solar panel.
Battery
The DXM solar controller is designed to use a 12 V lead acid battery. The characteristics of a solar system require the
battery to be of a certain type. There are basically two types of lead acid batteries:
• SLI batteries (Starting Lights Ignition) designed for quick bursts of energy, like starting engines
• Deep Cycle batteries - greater long-term energy delivery. This is the best choice for a solar battery.
Since a solar system charges and discharges daily, a deep cycle battery is the best choice. There are different versions of a
lead acid battery: wet cell (flooded), gel cell, and an AGM (absorbed glass mat).
DXM150-Sx Wireless Modbus Slave
26
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