Understanding the Solar Power Kit
Page 7
U
NDERSTANDING
THE
S
OLAR
P
OWER
K
IT
You may be interested to know something of how the kit operates. Aside from
the installation hardware, the kit consists of three key elements—solar panel,
battery, and regulator circuit:
✦
Solar Panel
Converts solar energy to electrical energy. The unit provided is rated at
0.5 Watts. It provides about 50 mA of current in bright sunshine
(1000 W/m
2
). In 2 hours it will provide enough power to operate an a
SensorLink transmitter for 10 days.
Note:
You can clean the solar panel with a water spray, or with a soft cloth and soapy water fol-
lowed by a clean water rinse.
✦
Battery
The kit is designed to use the 1.2 Amp-Hour battery provided, but any
6-volt rechargeable battery may be used. The 1.2-Amp-Hour battery,
when fully charged, can supply power to operate a SensorLink
transmitter for 300 days without recharging, assuming an average
temperature of 68˚F (20˚C). It will run for about 250 days at 32˚F (0˚C)
and about 200 days at -4˚F (-20˚C).
CAUTION:
The battery is sealed, but it should be assumed that it (and any other rechargeable battery)
is capable of generating flammable gas. No spark, flame, or lighted cigarette should be allowed in
the vicinity.
✦
Regulator Circuit
In order to increase the efficiency and life of the battery, the circuit limits
the voltage to which the battery is charged, and it adjusts this voltage
according to the temperature at the rate of negative 7.5 mV per ˚C. This
ensures that the battery is fully charged for the conditions, but never
over-charged.