Hi there,
The built-in solar panel is mainly designed to maintain daily power, so we strongly recommend giving it a boost via USB:
Remove the battery pack from the back of your Pixie and plug it into a standard 5V USB charger using a USB cable to bring it back to full charge before reinstalling it in direct sunlight.
If the battery was completely drained for an extended period, it may experience capacity degradation. If you find the battery no longer holds a charge well, you can trade it in for our latest Pixie-2 with an upgrade discount. Feel free to contact us at support@netrohome.com with your device details if you’d like to explore the trade-in option!