[pct-l] Phone charging

[James Vesely]

I have a limited number of high grade solar panels for sale they are 7" x 10" in size and are made with high efficiency monocrystalline photovoltaic cells (17+ tested efficiency)  I have tested the panels on a clear winter day and they put out an amazing 750mah at 5 volts and I believe that if it were summer they would put out closer to 1 amp which is a true 5 watt panel.   The panels weigh 5.5 oz and that includes a voltage stabilizing CB and housing with a standard  5 volt USB output plug.    I have also weather proofed the USB housing so as to be rain resistant. 

The panels are not flexible because high efficiency monocrystalline cells cannot be made that way .   These photovoltaic cells are mounted on a lightweight circuit board material and then laminated with a PET material for durability.   They are very sturdy and would be rather difficult to break.  

I have been researching this for a couple of years now and found that for their weight there is nothing more efficiency then monocrystalline cells except multi-junction cells which NASA uses and are in the $300-$400 per watt range.    The panels can charge any phone but I would highly suggest charging a portable 2000-3000 Mah USB backup battery instead especially  if you are going to hike and charge at the same time.  Direct charging of your cell phone is the most efficient method but cell phones do not like intermittent charging which can obviously occur whenever you pass shady areas.   

I have also tested some USB battery backup options and all I can say is buyer beware.   Battery capacities are HIGHLY exaggerated for example I recently purchased some 18650 type Li-ion cells advertised as 5000 Mah only to be tested at less than 900 Mah (your cell phone battery is around 2000-3000 Mah).  I suggest looking at the reviews for any particular battery backup and look for the words "I tested the capacity".    The website Adafruit advertised a couple these as being acceptable.   Also all charge/discharge systems have inefficiencies so you probably will not get a full 3000 mah out of a 3000 mah battery backup. 

If anyone is interested I have 9 panels and I am asking $75 each with postage included. 

Pictures are at this link.    

https://plus.google.com/photos/100489363658004251804/albums/6111287435181323441



-----Original Message-----
From: Pct-L [mailto:pct-l-bounces at backcountry.net] On Behalf Of Wilde, Myles
Sent: Sunday, February 01, 2015 5:37 AM
To: Ron Graybill; Tom Grundy
Cc: pct-l at backcountry.net
Subject: [pct-l] Phone charging

Hi All,
I'm curious how all you phone users keep your phone charged on multi-day hikes?
Do you use solar chargers? If so, do you charge while hiking or only when you've stopped?  Any recommendations?
Thanks
Myles