Hello!

[HaNd_SoLo]

I'm new to all this, looking for advice on setting up a grid backup battery system (eventually with solar).

[Mike90250]

Welcome. First step is to get a copy of the book Solar Power for Dummies. That book covers a lot of ground, and will get you closer to the point where you can ask questions that we can answer.

Generally, every solar install is different. Some companies have a Medium and Large choice for you,

Expect battery backup to cost a lot more than a generator and fuel source

[bcroe]

You will get dependable performance for the least cost per Watt with a generator,
powered by gasoline, diesel, propane, or natural gas. Bruce Roe

[J.P.M.]

As Mike writes, get educated before you spend dime one. But first identify your goals and what you want to accomplish.
Avoid asking vendors questions before the read. You'll get screwed less.
Then, come back here and fill in knowledge gaps your education creates by asking questions. Sometimes a bit of a thick skin helps. Nothing personal.
Do preliminary sizing with your gained knowledge and something called PVWatts (on the net, from NREL).
If a cost effective system is one of your goal, know that oversizing is the fastest way to make a system non cost effective. Your choice, just know the consequences of that choice.
Then, get quotes from at least 3 local, licensed and reputable electrical contractors who've been in business for at least 10 years and sold PV for at least 5 or more of those years.
During the vendor interview process, or anytime for that matter, never ask a question of a vendor that you don't already know the answer to. A goood way to spot who's B.S.ing you and also who knows what (or doesn't)
Avoid low dollar. Negotiate tough but fair and remember everything is negotiable. Look for most long term bang for the buck. Your self education will help identify that elusive situation. Low initial cost is the errand of a fool.
If a roof mount, get your roof inspected and serviced. PV will last a long time. Give the roof under it the highest probability of lasting as long. You do not want to be chasing leaks under an array - ever.
Avoid the big national outfits. At this point in your knowledge quest, you'll probably know more than most of the nitwits working for those outfits anyway. Besides, local is a better job, and with some sharp negotiating really cost competitive.
Avoid what amounts to hearsay from friends, neighbors and places like Angie's list. Such sources know less about the subject than you currently do as you'll find out once your self education begins.
Know what your loads are and reduce them as much as your chosen lifestyle permits before you get any equipment.
Know your POCO (POwer COmpany) policies and particularly their rates rates for power. Those are usually a PITA to understand (particularly rate structures) but are essential to know if a cost effective system is one of your goals.

Right now, battery backup systems are still pretty expensive and may need more baby sitting than vendors will tell you. For now, get a generator and wait for battery tech. to get easier to use and cheaper.

Welcome to the forum of few(er) illusions.