31988Solar phone charger field test -- successful?
- Jun 22 5:52 PMGot the $24 charger listed on ebay for 5 volt phones like my Samsung Galaxy. That was $24 total delivered direct from China. Got here in less than a week. (A completely safe and credit anonymous transaction with PayPal.) Model number is YG-020, Rating is 2.5 watts and small enough to go on the top flap of my Osprey Exos 58 pack. Take a look at the pic on ebay, 2.5W Portable High efficient Solar Panel Power USB Battery Charger for Cellphone. Auction item 350764161686. Other sellers have identical product, that's the one I happened to use. I wanted to go economy plan until I see if solar charging on trail is really worth it to me. 2.5 watts seemed like enough.
Plugged panel into dead discharged phone at 7 am, very low slanting sun, with panel aimed at the sun and got a 9% charge in an hour. That's a small charge, but encouraging. Using this panel for several afternoon hours in the prime high sun time with panel flat on a table got the charge to over 40%. At 4:45 pm it's up to 61%. That's with phone turned off except to check charge percentage. Sorry couldn't record accurate timings today, too many interruptions. But the point is made that this panel can put a healthy charge into my phone. Don't know if it can go from zero to 100% in one day, but maybe.
Note that these results are with panel in constant direct sun. That will not be the case when traveling with it on the pack top all day. I expect significant shading to happen. My goal is to be able to use phone for a maximum of 2 hours a day. That's for position check on the nifty Guthooks JMT map, including seeing my dot on the elevation profile, and then playing music before sleepy time. If I can stay ahead of that much usage with this panel on pack, I'll be satisfied. An hour long lunch break with panel aimed continuously at the sun should go a long ways toward that 2 hour usage mark all by itself. We'll see.
Problem is the sewn case for the panel weighs 128 grams. By cutting straps, clips and mesh pocket off, removing the vinyl window completely, then cutting a window in the back panel to match the window in the front, it gets down to 47 grams. The solar panel with a USB socket on it is 170 grams. The cable comes with 6 adapter tips, including the micro USB the Samsung needs. I already had a USB to micro USB cable, so I can use that without using the adapter that came with the unit. One less thing to lose, and no worries about a loose connection developing at the adapter tip. I tied the panel to the Osprey top flap with 2 short pieces of 1/8" elastic cord through the metal grommets in the case. Phone goes inside the zippered top flap just below the cased panel.
The total weight with a 15 gram cable is 232 grams or 8.2 oz. That's not light enough for me long term, but OK for this affordable and fun experiment. If it works out well I'll be looking for a much lighter panel with similar ratings for my next long hike. Or making one. Maybe with amorphous panels which can be much lighter than the crystalline ones like this one, but have to be somewhat larger because of lower output.
I'll be taking this rig on a 3 day JMT prep backpack next week and will post how it worked when I get back.
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