May We Discuss Solar Cell Phone Chargers?

I attended what amounted to a survivalist lecture for older adults last week.  One of the items strongly recommended for purchase was a solar powered cell phone charger.  I can see the merit of having an alternative power source to electricity for powering what can be an essential means of communication during a prolonged power outage (I was out for 10 days following Superstorm Sandy as were many of you).  Question is do these things actually work?  Do they generate enough charge to keep the phone operating for long enough to prove a useful addition to my digital device supply?  My son recommended the big blue solar charger (which looks like the portable solar panel it is) coupled with an Anker series 5 power core, which is compatible with my cell phone.  Would this work?  What can I expect in terms of cell-phone time if I go this route?  What other questions have I not asked that need to be considered and what is the answer to those questions.  Thanks in advance for your input.  In replying, please keep in mind that the abacus was the predominate computer when I was growing up and all telephones had a wheel on the front which was used in dialing the party you wished to reach.  

I guess the answer depends on what caused the outage. Another Sandy with power out for a few days, your cell pho ---  I started to answer and then became overwhelmed by the variables.

Another Sandy, snow storm, east coast power failure, something else I ain't thought of. Then the age of your phone's battery. The number of cells in your solar charger. How many sunny days in which use the charger. The capacity of the power bank that will diminish with its age. Your phone battery capacity will also diminish with age.

AND how often you will use the phone. If power is out, you might use the phone more than usual because there is nothing else to do. OR You might be wise and save all the power for an emergency.

For a real emergency, I have an emergency signal beacon. But it needs to be outside in order to send a distress signal. It does work. I came on a hiker, face down on a trail and it contacted emergency services.

But in answer to your specific question, we have a four panel solar generator at the swamp. It charges the batteries for our power tools.

What else did the survivalist person recommend? 

Also, what did s/he charge? We might want to hire a senior survivalist for our hiking club.

Jack:  The program was hosted by Friday Friends, the weekly senior group meeting sponsored by the Township of Millburn. I don't know what the speaker's fee was. The speaker did bring a lot of recommended emergency preparedness items to show the audience but did not offer any of them for sale. Other items recommended by the speaker included three day supply of water and shelf stable foods, first aid kit, manual can opener, water purification tablets or equivalent, flashlight, crank radio, extra blankets etc.  These are items I already have with emergency preparedness in mind.  The solar cell phone charger is something I had not thought of.  Thus, starting this thread to explore the idea and get feedback.  

I live in a hurricane-prone state, and I keep a power bank charged for emergencies. It can charge a phone multiple times, along with other USB-A and USB-C devices (ebook reader, tablet, hearing aids).

This is the one I currently have https://www.amazon.com/gp/product/B08JV4W4NY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 It goes on sale, or Amazon offers coupons, pretty regularly

https://www.cnn.com/cnn-underscored/reviews/best-portable-solar-chargers

Jaytee said:

https://www.cnn.com/cnn-underscored/reviews/best-portable-solar-chargers

Thank you so much.  This article not only points to the value of having a solar charger on hand in the event of a prolonged emergency but recommends both pieces of equipment that my son recommended.  Highly encouraging.