Should work fine. Issue is how you keep it waterproof both when charging - mobile wont like getting wet and my experience is lockers etc even if they are reasonably water tight the minute you open the hatch you will get some water inside from spray, rain or wet gloves, oilies etc.
The second complication is that you'll want to keep the ports dry when not plugged in. That means condensation free too...
The Blusea USB charger will be undoubtedly be the best in terms of quality, their stuff is normally the dog's danglies. Then you just have to decide where to install.
The new Samsung Galaxy 5S is waterproof... go on treat yourself!
there are various alternatives to the S5 which are waterproof - but to my knowledge none (including the S5) are waterproof whilst charging?
....and I think that different manufacturers have differing views on "waterproof". I've yet to see one that says you can dunk it in sea water.
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Your link says: "If you are planning to conduct your own Galaxy S5 waterproof test then be sure that all ports are properly closed and remember that the smartphone is only certified in fresh water, so don't take it in the ocean."
Just use one of the rechargeable battery pack ones of ebay. About a tenner of ebay that would charge your phone a couple of times. Or get a bigger one. Can leave in coat pocket or a map case. Easy
I'm interested in doing something like this on my SIB but I have no idea how to attach it to the outboard.
My OB does have a power output but it's AC. Would I need a rectifier? Would I need a battery? Or can one of these units be connected straight to the DC side of the rectifier?