When backpacking, camping, or preparing for an electrical grid-down scenario, solar power is one of the most reliable alternative power sources. Solar panels passively collect power from the sun with no other inputs or fuel. In full sunshine, this 21 watt fold out solar panel can provide 2.4 amp USB charging.
In the picture below you can see the solar panel securely attached to the backpack.
Devices and Batteries Charging Plan
In full sunshine, this solar panel would charge most cell phones and tablets. I recommend charging devices before charging backup batteries to prevent power loss. Charging a battery, then charging a device from that battery uses more power than just charging the device directly and skipping the battery. Batteries are very useful when the sun is not shining, so be sure to charge up backup batteries if the sun is still shining after charging devices.
Updated Charging Information:
Click below to watch the video of the Solar Panel charging a 20000 mAh battery.
Full Sun Charging (2.4 amp):
- 1.5 hours for tablet
- 1.0 hour for Samsung Note 2 cell phone
- 2.0 hours for 4000 mAh USB backup battery
- 5.0 hours for 10000 mAh USB backup battery
- More than 10 hours to charge a 20000 mAh battery
Cloudy Overcast Charging (1-2 amp):
- 2.5 hours for Samsung Note 2 cell phone
- 2-4 hours for 4000 mAh USB backup battery
- More than 5 hours for 10000 mAh USB backup battery
- Will not charge a 20000 mAh battery unless there is enough sun light to provide the required 2.4 amp
*Results may vary if the solar panel is charging while on a moving backpack.
You can see in the picture above that the solar panel has 2 USB PowerIQ outputs. I would recommend using both ports only when in full sunshine and with two devices that only require 1 amp for charging. If you try to plug two cell phones in at once - they will take a very long time to charge.
1 amp USB Chargeable Devices (from previous post)
In the picture below are many useful 1 amp USB chargeable devices: USB Chargeable battery, 2-way Radio, Cigarette Lighter, Pen Flashlight, Lamp Flashlight, Digital AM/FM Radio, Bluetooth Radio and Speaker, and Geiger Counter (not pictured).
In the video below you can see the solar panel charging a 1 amp chargeable 4000 mAh USB backup battery in overcast snow storm conditions.
You may find these previous posts useful:
- USB Induction Charging with BioLite Camp Stove - Burns Wood - Boils Water
- Back Acres: Small Knife Sharpening wit a Pocket Sharpener - Regular, Serrated, and Gut Hook
- Wilderness Survival: Starting a Fire with a Ferrocerium Rod - Multiple Methods
Have a great day!