First, awesome. Cool project--I too am now dependent on some medical equipment needing power (for me to breath when I sleep) so I too have done a solar/battery thing. Since I am a little OCD, I have done a lot of research into bang/buck for power and what I have found (weight not a factor, at least not much) is that the 6V golf cart batteries, connected in series for 12V is the best bang given storage/cost/deep cycle use into consideration. So if you go for extended trips into possibly not so sunny areas, might be handy. I'd be happy to share more, if you'd like---and check out expedition portal for some tips on this topic as there are a number of diabetic/fridge dependent folks there that have some amazing set ups....
That said, aaaaawesome job!!!