https://sierramadreresearch.zendesk.com/hc/en-us/articles/4487495014171-How-many-solar-links-do-you-need-to-charge-a-Powerpack-in-an-hour-

https://sierramadreresearch.zendesk.com/hc/en-us/articles/4487495014171-How-many-solar-links-do-you-need-to-charge-a-Powerpack-in-an-hour-

 

If you're trying to figure out how fast you can charge your Power Pack, here's how it works.
Take the total number of panels you have, multiply them by 7.
Now divide that number into your Power Pack's capacity,
The Power Pack UL (40.7 Wh) or Power Pack XL (81.4 Wh). This will give you the charge time in hours.
Let's say you have 3 panels (a Base + 2 Links) charging your Power Pack UL, so you multiply 3 x 7 = 21.
Now divide 40.7 by 21 = 1.93 hours. So with three panels, you can recharge your UL in about 2 hours.
Now keep in mind this would be under PERFECT conditions. We're not accounting for energy loss or clouds.
BUT that gives you a great starting point in thinking through how many panels you need to stay charged up!