480W with the 4 T105 batteries will probably be OK. We're a family of four with loads of electronic devices, a CPAP machine and an inverter than runs 24/7 for a residential fridge. We have 400AH of LiFePO4 batteries and about 700W of solar. On nights we don't run the heat, in the AM the batteries are down about 100-150AH. On a recent trip to DC we stayed at Greenbelt National Park's campground in partially shaded conditions and the batteries were topped off around 2-3PM every day. In full sun they top off before Noon. During colder weather when we need to run the heat the batteries are drained more, about 200-250AH, and with the weak winter sun may be topped off by sunset or we will run the genny.
If you can avoid running an inverter 24/7 that would be a huge savings. Ours takes 3A just to run, so over 24 hours that's 72AH! Note some of this time it is being powered by the panels, of course.
BTW, I agree with PJStough, the kits will generally not have heavy enough wire, etc. I used Handy Bob's advice extensively when I designed my system, except for the part where he wanted 12V panels and PWM controllers. The 24V panels with MPPT controllers turned out to be cheaper overall, especially as I sourced the panels from
Sun Electronics, who consistently have the cheapest panels per watt.
also an energy monitor is a must, PJStough mentioned the Bogart Engineering brand, I've used the Bogart 2020, an old Xantrax
Link 2000 system and now a Blue Sky Energy
IPN Pro remote that links with my charge controllers and would recommend any one of them.
Here,
here and
here are a few posts on my system you might be interested in. PM me if you want more details on how I installed the panels on the roof.