First off, I admire your creativity!
Just a few small points, that battery would be lucky to be any more than 10aH, meaning you'll get about 3 full charges of a 11.1v 2200MaH, but it would struggle to charge the vision 5200MaH battery twice. Also, it looks to be a "flooded" lead acid motorcycle battery, meaning its likely to seep battery acid when tilted and also can produce flammable gasses while charging.
The solar panel would be no more than 5Watts (I'm being generous there) so in full sunlight it would be pushing out about 0.4A at most. 5W/0.4A would take 25 hours (continuous sunlight) to charge a 12v 10aH battery, or 6 hours for a 2200mah battery, and 12+ hours for a 5200mah Vision battery.
. . . Also, all those numbers are ignoring power used by the inverter and charger, and assume 100% electrical efficiency.
I was thinking of making a similar box, I almost have, but I'd rather go without the solar (or pay big $$ for something that'll pump 3A+) and invest in a larger battery, tho that'll increase the weight a fair bit too, I did invest in a 12v charger I can run of a car (that bypass the power used by an inverter!) now once I use all my batteries (or when I'm down to my last 1 or 2) ill put the rest on charge in a vehicle and I'm able to continue flying (with someone else watching the charger) this almost allows me to fly around most of the day, currently with only 4 "flight" batteries.
But still, nice work
