PROJECT: Introduction to Solar Panel Project

Introductory post about possible project:

Installing Solar Panels behind Rear Headrests

Dashboard trickle chargers are being introduced to keep the 12V car battery. It would be useful in situations like camping and road-trips but would not be necessary for most Joe's. Nevertheless, solar power might be of some use for a Joe and let's look into it. Instead of the dash, placing solar panels behind the rear headrests of a medium sized sedan seems more appealing. Less clutter and possibly a safer option if wiring is not an issue.

Possible uses for the extra electrical power:
- Running a small fan to cool the car while ignition is off.
- Charging your smartphone (Androids in particular).

PROs:
- Extra power source
- Time is not a concern in charging battery
- Cool factor
- Educating experience

CONs:
- Additional sprung weight
- possible glare
- Costs vs Benefits
- Tinted windows reduce the amount of power received in solar panels
- Time
- safety (ie glare while driving, overheating, fire)

Rechargeable battery life is a priority. Possible places to place the battery would be in the center compartment, glove compartment, or trunk.
These are some options for consideration:
i) Lead / Acid battery packs
ii) Lithium-Ion or Nickel-Metal Hydride (pulled from old laptops or cordless and cell phones)
iii) Wire rechargeable batteries in series

The specifications for the HTC wall charger, battery output to USB cable should be 5V & 1.0A.
Therefore 5 Volts x 1 Amp = 5 Watts maximum should be transmitted to the smartphone.

Suggested specifications of the project:
- With a maximum input of 5 Watts charging a cell phone battery, a solar panel receiving about 5 Watts is sensible. Tinted windows supposedly reduce the power solar panels receive through glass by about 20%. Therefore: 5 Watts / 80% = 6.25 Watts maximum. A 6V / 5W solar panel, like the KS-M200200G, would be a good starting point.
- For a daily driver content with an extra charge in the car, wiring 3 rechargeable D batteries could work (Each battery gives an output of 1.5V, therefore 3 x 1.5 V = 4.5 V).
- Would need to attach a heat sink to the transistor for cooling.

Figure 1: Basic circuit diagram for solar panel project (suggested to me)

USB Layout:

Figure 2: Layout of different Universal Serial Bus receptacles

For 4 pin receptacles:	For 5 pin receptacles:
Pin 1: VCC, +5V Pin 2: D-, Data - Pin 3: D+, Data + Pin 4: GND, Ground	Pin 1: VCC, +5V Pin 2: D-, Data - Pin 3: D+, Data + Pin 4: ID, not connected Pin 5: GND, Ground

Conclusion: Right now the prices of solar panels are too expensive to justify a project like this. If solar panels become cheaper or a great deal for one is found somewhere, this project would be worth considering.