It'll take about 30 minutes to bring 2 gallons of water from 20C -> 80C using a 1500W (ie 1500J/s) heater assuming adiabatic conditions. That's fast enough to get it a boil as long as nothing is drawing away heat too quickly. I wrote about the calculations, but I don't see them here.
It takes about 4J to heat 1g of water 1C. You need to heat about 7.5L by 80C. You can do the math and see that I'm not too far off with my estimate.
Your setup will be fine.