You would be far better off to purchase a commercial unit than to try to build something yourself.
It will wind up being less expensive and more efficient.
Just to throw some numbers at you, a power inverter might have around 87% efficiency.
So to get 1,300W out will require nearly 1,500W input. (1.3kw/87%=1.5kw)
If you're running from 12v batteries, then 1500W/12v = 125 Amperes of current will be required.
You would need a large bank of high-capacity 12v deep-cycle batteries to supply 1300W for any length of time.
You would also need a means of recharging that bank of batteries.
Charging/discharging lead/acid batteries is certainly not a 100% efficient process. More like 70%. Losses in the charger itself are not included.
You would need a large and expensive solar array, or very efficient line-powered charger(s) to recharge them.
You ought to be able to find a used 1500 watt inverter on E-bay, or by canvassing the local garage/ yard sales. If that doesn't work, put an ad in your local paper. Even the local junkyard might have one on the shelf. I just bought a very high class computer controlled Sansui turntable at a local thift store for $25.00. Shop around...high tech devices are as common as mushrooms nowadays.