105 Radio/Serial Telemetry Module
User Manual
Page
14
©
January 2004
Upon failure of the normal supply, the 105 module may continue to operate for several hours from a
backup battery. The 105 module includes battery charging circuits for charging up to a 12 AHr
sealed lead acid battery. The battery is connected to the "BAT+" (positive) and "GND" (negative)
terminals. The positive lead from the battery should be protected with a 2A fuse, installed as near to
the battery terminal as possible. On return of main supply, the unit will switch back to mains
operation, and recharge the battery. To provide adequate current to recharge the backup battery, an
AC supply of 15V minimum or a DC supply of 17V minimum must be used. Typically, a 6 AHr
battery will supply the 105 for 1 - 3 days, depending on I/O loads.
2.3.3
Solar Supply
The 105 power supply also includes a 12 V solar regulator for connecting 12V solar panels of up to
30W, and solar batteries of up to 100AHr. An 18W solar panel is sufficient for most solar
applications. The size of the solar battery required depends on the I/O used. Batteries are sized for
a number of sunless days with 50% battery capacity remaining as follows:
No. of sunless days = Battery capacity (AHr) x 0.5
Module load (A) x 1.2 x 24
The Module load depends on the I/O connected and can be calculated as follows:
Module Load(A) = 0.07 + (0.01 x No. of DI’s) + (0.025 x No. of DO’s)
+ (2 x Analogue loop load).
The analogue loop load is the total signal current for the AI’s and AO’s which are powered from the
internal 24V supply. Externally powered loops are not included in this.
The solar panel is connected to the "SOL" (positive) and "GND" (negative) terminals and the battery
connected to the "BAT+" (positive) and "GND" (negative) terminals. Solar panels must be installed
and connected as per the panel manufacturer's instructions. The positive lead of the battery should
be protected by a 2A fuse installed as near as possible to the battery terminal.
Where a panel larger than 30W is required, an external solar regulator should be used.
Note: The unit must not be powered from a solar panel without a battery.
For maintenance,
disconnect the solar panel first before disconnecting the battery
.
_
+
SUP1
SUP2
GND
SOL
Power
Supply
DC Out
BAT+
GND
105U
11.5 – 15 VDC
Fuse 2A
_
+
SUP1
SUP2
GND
SOL
BAT+
GND
-
+
105U
Solar Battery
Fuse 2A
Solar Panel