solar panel _inside_ kayak???

This guy claims to charge his fishfinder battery using a solar panel mounted inside his kayak:



Is this plausible?

Plausible, but not efficient. Stick your head inside your yak out in the sun. It's plenty bright in there. Bright = photons = electricity.

Assuming it'd work way better out on the deck.

 
  It looks like it's installed thru the hull.  That panel is small so the battery won't get a full charge while being used. Perhaps after a few days of direct sun a small charge may be applied to the battery. But hey, any charge is better than none!

I use a waterproofed VW solar battery maintainer (Avail on Ebay) works great. Seems to keep my battery up even with my Lowrance chirp set to high frequency sonar (fast pulses)

 http://www.ebay.com/itm/Volkswagen-VW-Solar-Panel-Car-Battery-Charger-Maintainer-1C0-915-687-DC-Voltage-/351565166974?hash=item51daeab97e:g:wA0AAOSwu4BVw6PW&vxp=mtr

Clear drybag (or large ziplock) bungeed to deck

don't get the OBD2 type, need modification before use. Doable but standard plug type is easy