Thanks,
Yeah good point about not shutting down properly... its still working so far!
No doubt a fun python learning experience! For volatile installations like this I'd probably swing the Arduino route just for the sake of eliminating OS corruption. It may never happen to you or it may happen every month--all depends on image version and what is running on it and pure luck sometimes.
Currently running a single 100AH deep cycle battery. Its got a picture of a guy with a fish on the front. I tried to find the recommended charge settings etc. but could not! So my PWM charge controller is on defaults, but i think it tops out at around 14.5V and cuts off at 12.5V. Those numbers sounded fairly safe. Last night however the system cut out at 1:30am. So it definetly didn't have enough charge. I'm thinking its mostly a case of just not having enough battery capacity. After doing some quick wattage calcs in my head I guess all this gear would be pulling around 50 watts/hr, will have to think about this a bit more. Would be awesome to have the pi (or something smart - switch etc.) give me live voltage readings. I have another of these batteries, so i'll wire it up for 200AH. My latitude is ~36 degrees S.
Others have provided good insight so far on this as well, but I'd say the more you shave off of this energy consumption wise the better. 50w/hr is a little intense and my guess is the cam is mostly responsible, but anything else that can be removed should be. The .8a/12v fan would be my first elimination despite the heat. Perhaps a lower wattage fan could work.
Having some drama with the 3g box. Plan is to run openWRT, or more specifically the aussie "rooter" derivitave which is built to make 3g modems work easily, and have it connect home using openvpn. It gets a dynamic public address, so i was hoping i could set it to reboot and just connect to my openvpn server (somehow)...
Picked up a TP-link MR 3020 to plug into that old router, and a 3G modem i have here. the 3g modem is "host-less" so it presents itself as an ethernet device to the tp-link. I probably could, but haven't been able to get vanilla openwrt to use this 3g modem properly (the linux usb commands are useless for this modem) - but it works sweet with rooter.
The problem with that TP-link is it has 4MB ram, and as such doesn't fit openvpn on it easily. If i made my own build of openwrt it could be done, but I dont have the time to learn how to do that right now.
Picked up a cheap tp-link WR842N to replace the old router and other tp-link, but they sent me a different version to what I ordered, and it isn't supported fully by openwrt or rooter! pretty annoying.
I can get a 4 or 8 gig/month plan here, so hoping for some kind of continual recording (even if its at lower quality) and high quality live view.
So yeah! (once i get a decent router) do you think my plan will work?
This is where I come in with advice/critique/sad news. The hardware isn't going to be your demise, but if you're planning on using any of that on solar, consider revising the hardware list to simplify it immensely--starting with the netgear wifi switch. Your total power for ALL networking components should be less than 3-4W. Focusing just on the networking/software, you'll find that OpenVPN will be too "chatty" on a 3G/4G connection. In other words, a constant VPN connection like that will cost you bytes per second which add up over time.
Planning and executing a cellular based IPCam setup isn't for the faint of heart 
A lot of focus with standard installations is on gigabytes, megabytes, etc... but with cellular you have to focus on bytes. Not kilobytes. Assuming OpenVPN isn't too chatty, you can still expect its keepalives to easily cost you 300-350MB/mo on low end--and that's just to keep the connection alive. Any data you wish to push through is on top of that.
Continual stream of even ~40kbps will cost you around 11-12GB/mo I'm estimating. To get an idea of what that looks like, pop open your Dahua and set it to the lowest stream it can handle. Then PTZ around to see how it fights between iframes.
This isn't to scare you away from it, just some things to consider. There are ways of doing this (minus 24/7 stream) inside of 1-2GB/mo. and still have everything sit at a beautifully encoded 1080p w/o noticeable compression. It's just a math game. Some of my 4G installs when I started doing this went over 2GB/mo but it wasn't hard to catch the data leaks to prevent it from happening again. Most I have sitting at 1GB/mo with off-site storage, 1hr FTP snaps, and live view, but again it's all about monitoring every byte to make this as efficient as possible to do everything you want/need to do.
