Dale from the Survivalist Prepper (www.survivalistprepper.net) set a challenge for any members who wanted to participate.
The idea is to send a box with some supplies (no more than $20 worth) and a small list of challenges that they would like the recipient to complete in a 24 hour period.
The recipient will need to make a video or take pictures of what they have done and share it with everyone else. The purpose is for learning something new and to have a bit of fun along the way, but nothing dangerous or illegal.

As I reside in the UK and Dale in the USA, to keep postal costs to a minimum we used Amazon as a selection and local delivery option which worked well, a package arrived last weekend with instructions sent to my wife by email.
My Challenge was to evaluate a low cost solar USB charger that Dale had provided.

The unit is a GRDE 10000mAh Outdoor Solar Power Bank; it comes with a USB lead with adapters Nokia DC 2.0, Mini USB, Micro USB & iPhone.

I have given this an overall rating of  6/10 .

I consider this to be a reasonable unit for the cost, its has a good selection of accessories and the dual USB ports are very useful. It is let down by the potential fragile casing and the annoying resonant noise at full solar charging.  Also despite having the unit in the sun all day the best that I could achieve was a 25 to 50% capacity. So my estimate is around 3 days for a full charge via solar.

My Assessment

Upon opening for the first time you notice the immediate attempt for the unit to charge via the solar panel indicated by flashing lights even when indoors at night with an electric light lit.

Some of the available data on the internet from sellers had recommended at least three full charges via the mains before solely relying upon the solar charge.
Having read that the GRDE had five intelligent protection systems to prevent, over current, short circuits, over discharge, voltage protection and overcharge, I felt confident enough to charge the unit overnight via the mains electric.
Over the past week I have carried out 4 specific tests (full details of the results included below)

Multiple Device Charge 9/10

The first three tests evaluate the capacity to charge multiple devices, multiple times are a 6 day period with no recharge.
Overall, I was impressed by the amount of device charges that could be obtained from the stored charge of the GRDE.

Test 1 – A dual charging test using the two USB ports on the GRDE, a Nokia Lumina & Nexus 7 with 11% and 70% remaining capacity, both devices achieved 100% charge in 2 hours 45 minutes.
Test 2 – Without any recharge and covering up the Solar panel to stop additional charging, the GRDE was used two days later to charge a Blackberry Curve 9320 with 0% capacity. A full charge was obtained in 2 hours 10 minutes.
Test 3 – Again, as in Test 2, the GRDE was not charged or allow to charge. A Nokia Lumina with 10% capacity was charged for 1 hour 30 minutes before the charger unit auto shut off.

Continuous live feed 9/10

The fourth evaluation was to test the continuous feed for a portable low voltage CCTV camera, in this test the video continued to record for twelve hours thirty minutes. The day was overcast so did not provide high solar charge,

When the vehicle was stationary the solar unit was placed upon the dashboard to maximise the charge, when driving the device was placed on the passenger seat.
For a survival use, being able to set up the device to provide a continuous live feed to a CCTV camera remotely, i.e. remote surveillance is a good additional use for this device.

LED Torch 2/10

The unit has a single LED light; whilst this will suffice for very basic close lighting work, it doesn’t function very well as a torch, but of cause is better than nothing in emergencies.
Durability 4/10
The casing is hard plastic that will probably not withstand any drops without breaking, I would recommend a foam lined case for carrying and outdoor use.

Solar Charging 4/10

The solar charge appears to be easily activated, however the charge rate indicator LEDS show slow recharging of the internal storage battery, the unit also has an annoying buzzing sound that gets louder with the strength of the sun’s rays. Despite putting the unit in strong direct sunlight for a whole day it still only managed to charge its internal batteries 25 to 50%.

Mains Charging 8/10

With the safety features including in the device the unit can be left for extended periods without being concerned about overcharging.
Value for Money 8/10

Amazon.co.uk has the GRDE for sale at £18.99 ($19.99 Amazon.com), for the cost I consider this be good value for money.

Full Test Data
Test 1: Nokia Lumia 635 with 11% battery remaining & Nexus 7 with 70% battery remaining
The Nokia has a Li-Ion 1830 mAh battery (BL-5H), at 11% capacity I have assumed that the level is 201 mAh and therefore the charge required would be 1629 mAh.
The Nexus 7 has a 3950 mAh battery, at 70% capacity the remaining charge required is 1185 mAh.
Devices were kept on during the charge, the Nokia was powered off, the Nexus was in standby, and all services were enabled.
Solar charging was enabled using the dusk sun between 19:30 to 21:00 hours and checked periodically with the following results:
• 20:00 – Nexus 65%, Nokia 35%
• 20:35 – Nexus 75%, Nokia 55%
• 21:00 – Nexus 85%, Nokia 71%
• 21:20 – Nexus 89%, Nokia 91%
• 22:00 – Nexus 98%, Nokia 99%
• 22:15 – Nexus 100% , Nokia 100%

At the end of the test the solar unit still had 3 out of the 4 LEDS lit (50 to 75% capacity).

Leaving the solar unit in its packaging to avoid any recharge for two days before attempting the next test, upon opening there was no apparent deterioration of the battery capacity. Keeping the solar panel shielded to stop any solar charging, the next test was to charge a single device.
Test 2: Blackberry Curve 9320
The Blackberry has 1450 mAh battery; the device was switched off due to a zero capacity battery.
The following charging results were obtained:
• 19:40 charging commenced
• 21:50 Full charge

At the end of the charge the GRDE still had 3 out of the 4 lights lit signifying 50 to 75% charge.
Again the unit was placed into its box and kept away from solar charge for another two days.

Test 3: Nokia Lumia 635 with 10% battery remaining
With the solar unit covered to stop solar charging, and still 3 out of the 4 charge lights lit, the Nokia Lumia with 10% battery capacity was charged, the charging time was 1.5 hours and reached 45% capacity before the solar unit switch itself off charging.

Test 4: HD 1080p LCD night vision CCTV in car DVR accident camera video recorder

This device takes a DC5V power input, using the 2A output feed from the solar unit, with a full charge (75 to 100%) and allowing the unit to charge via Solar the CCTV video camera recorded continuously for 12.5hours.