Intermediate

Solar Phone Charger

Create a small protected solar USB charger using ready-made charging and boost modules.

Safety first, always.

ElectroLab AI teaches theory, low-voltage electronics, and planning concepts. Mains voltage, switchboards, fixed wiring, high-current systems, and legal electrical work must only be performed by licensed electricians where required.

Open Safety Center

Build target

Learn solar input, battery protection, boost conversion, and load limits.

Build steps

1.Choose a solar panel that matches the charger module input range.

2.Connect the panel to a solar charge controller module.

3.Connect the battery pack with correct polarity and protection.

4.Feed the protected battery output into a USB boost converter.

5.Test charging current in sun before plugging in a phone.

What you are learning

1.Solar panels behave like variable current sources depending on light and load.

2.Battery charging requires chemistry-specific voltage and current control.

3.A boost converter raises battery voltage to 5 V USB output.

Bench tests

1.Measure panel open-circuit voltage in sun.

2.Measure USB output voltage with no phone connected.

3.Test with a dummy USB load before charging a device.

Fault finding

1.No USB output: check battery voltage and boost module enable pin.

2.Battery not charging: check panel polarity and sunlight level.

3.Module heats up: load current may be too high.

Upgrades

1.Add a fuse and power switch.

2.Add a voltmeter display.

3.Use a larger panel and battery with a rated enclosure.

Project safety

Use protected battery packs and approved charging modules. Lithium batteries can burn if shorted, overcharged, punctured, or wired incorrectly.