PS150/CH150 12 V Charging Regulators
14
6.2 Maximum Power Point Tracking
The current and power versus voltage for a 70 W solar panel are illustrated in
FIGURE
6-1
. As can be seen from the figure, a Maximum Power Point of
operation exists for solar panels. Adjusting the load on the solar panel so it
operates at this Maximum Power Point is referred to as Maximum Power Point
Tracking (MPPT). MPPT is beneficial when insufficient power is available
from the charge source, which is the case during current limited charging. The
somewhat noisy charging current and voltage during the initial current limited
charging stage is due to the MPPT algorithm of the PS150/CH150 searching
for the maximum power point of the associated solar panel.
FIGURE 6-1. 70 W solar panel I – V and power characteristics
7. A100 Null Modem Adapter
The A100 adapter has two 9-pin
CS I/O
ports with a null modem between
them. The ports are used to connect two 9-pin devices (e.g., modems or RF
radios) that would normally be connected to the
CS I/O
port of a Campbell
datalogger. The charger supplies 12 Vdc and 5 Vdc to the appropriate pins on
the connector for powering the connected devices. This functionality is
required in a station where a datalogger will not be present, such as a phone-to-
RF base station. The A100 cannot be used as a null modem between two
RS-232 devices.
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
0
0.9
1.8
2.7
3.6
4.5
0
10
20
30
40
50
60
70
Voltage (Volts)
C
ur
re
nt
(A
m
ps
)
Po
w
er
(W
at
ts)
4.5
0
I
m
70
0
P
m
21
0
Vc
m
