Amorphous Solar Power Battery Charger Kit by Harbor Freight
Watch the harbor frieght solar power battery charger part 2 here.
DS briefly runs through a series of current and voltage tests on the Harbor Freight 1.5 amorphous watt solar battery charger kit.
The harbor freight amorphous solar battery charger kit includes:
*One mountable solar panel with hard plastic bezel measuring 14-3/4″ L x 6-1/2″ W x 7/8″ thick
*Detachable vehicle adapter with activity LED (12V)
*Documentation
Formulas used to calculate the wattage from the solar panel:
Variables:
V=Voltage
I=Current
R= Resistance
W= Watts
V=IR (ohms law) (to double check calculations)
W=(I^2) R (reads: (watts = current squared * resistance))
Current measured (100 ohm resistor in series) 25 — 35 mA
Output wattage calculated in overcast skies (100 ohm resistor)=
W@ 25mA= 0.0625 (62.5mW)
W@ 35mA=0.1225 (122.5mW)
W@ 120mA= 1.44
Assuming you reach the advertised max current from the solar panel of 120mA you seem to max out at 1.44 watts theoretically. This is close to the 1.5 watt rating of the solar panel, but slightly less.
As a vehicle battery trickle charger, the Harbor Freight 1.5 watt amorphous solar panel- solar battery charger kit will work as advertised, however local conditions will always affect the efficiency of any solar panel. When designing a solar panel system, is it always best to overestimate the necessary wattage to compensate for environmental factors. The Harbor Freight Solar Battery Charger Kit is a great piece to familiarize yourself with solar energy, at a low cost. For $20, harbor freight has put together a neat, potentially outdoor use (need silicone caulk) solar panel perfect for powering small electronic devices or trickle charging batteries. Wire leads can be used in lieu of the 12V car adapter
to more easily power/charge other electronics.
Harbor Freight 1.5 watt amorphous solar panel- solar battery charger kit Product link as of 03/19/201:
http://www.harborfreight.com/15-watt-solar-battery-charger-44768.html
Stay tuned for updates, and a test run under better lighting conditions!