Learning Goals
- Students will be able to design a device that can charge a phone with 4 hours of sun a day.
- Students will use collected data and be able to support their design – i.e. the data will show that the unit will produce enough energy to charge a phone given it receives 4 hours of sun a day.
- Students will also be able to calculate efficiency from their power calculations.
- Students will be able to compare efficiencies of their circuit to others tested in this unit.
- Students can calculate how much energy 4 hours of sunlight can produce on the solar modules they will use.
Materials List
Group Supplies (2-4 students)
- Solar modules, assorted (3-6 V, 1-3 Watts) (about 2 each per group)
- Buck or boost converter – each group will receive one and they must work with this
- DC Power Plugs, male and female
- Shrink tubing and solder
- Wire strippers
- Battery Packs – depending on the group 2-AA, 3-AA, 4-AA, 6-AA, 8-AA and 10-AA
- (2-10) AA NiMH batteries, depending on the group (Warning: do NOT use Li-ion batteries for this activity!)
- Pelican waterproof case
- USB current/voltage meters
- Cell phone or device that uses a USB plug for charging – students can bring in a USB charging cord for their phone, or instructor can supply any USB charging device. I used LED bike taillights that charge with a USB.
Important Links
Next Generation Science Standards
Next Generation Science Standards
- HS-PS3-1. Create a computational model to calculate the change in the energy of one component in a system when the change in energy of the other component(s) and energy flows in and out of the system are known.
- HS-PS3-3. Design, build, and refine a device that works within given constraints to convert one form of energy into another form of energy.
- Off the Grid Lesson 7: Designing a Solar Phone Charger | Page 1 of 8
- HS-ETS1-2. Design a solution to a complex real-world problem by breaking it down into smaller, more manageable problems that can be solved through engineering.
- HS-ETS1-3. Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics, as well as possible social, cultural, and environmental impacts.
Featured Image Description
Drawn on a white board in red marker 12 V CAR CHARGER FOR USB DEVICE underneath is a circuit diagram showing a ATC Holder (empty) to battery pack (12V) with DC female power plugs coming off of it to the right the male plugs connect to a female cigarette socket. A male cigarette plug (car charger) connects to the USB meter with power lines connecting off the bottom of the image. All junctions are labeled as listed in the description.