Get some Nuun tablets. They come in a tube, fit in a small bike bag or jersey pocket, only have 5 calories, and are strictly electrolyte replacement. I hardly ever drink my calories on the bike, and prefer to eat real food or a Luna Bar while riding. If it's a long ride, I have one bottle of Nuun, one of plain water. Very rarely do I use Accelerade anymore.
Heat is a killer. You can get in trouble very quickly. I pre-hydrate if it is very hot.