Mobile Devices - Solar Charging Solution

So, I have three scenarios in which I would like to be able to charge various mobile devices:

1) While voyaging under sail
2) When backpacking
3) As an emergency power solution if the grid should fail (earthquake, etc.)

Here are some new bits of gear that I ordered today (happily, I was able to cover just about the entire order cost with Citi Visa ThankYou Reward Points, that Amazon now allows you to use to complete a purchase).

Anker 21W 2-Port USB Solar Charger PowerPort Solar 

• "charging speed up to 2.4 amps per port or 3 amps overall under direct sunlight. 21 watt SunPower solar array is 21.5-23.5% efficient, providing enough power to charge two devices simultaneously"
• "Compact size (11.1 × 6.3in folded or 26.4× 11.1in opened)"

[Most Compact 20000mAh Portable Charger] Anker PowerCore 20100 - Ultra High Capacity Power Bank with Most Powerful 4.8A Output

• "Weighs as little as a can of soup (12.5 oz"
• "charge up to 2.4 amps per port or 4.8 amps overall. Recharges itself in 10 hours with a 2 amp charger, phone chargers (generally 1 amp) may take up to 20 hours"

DROK USB 2.0 Digital Multimeter, Ammeter Voltmeter Capacitance & Watt Meter, 7 Modes Multi Tester, DC 3A 12V Amp Voltage Power Meter, Charging System Tester, Fast Charging and Data Sync Dual USB Ports

  

2016-03-06 Sunday Update:

I was able to test the equipment today, in the brief window of sunshine that appeared in Seattle this morning.  I noted ~5.1 volts, and 0.24-0.26 amps, at about 10:30am