Soak all the dals in water for 2-3 hours. Drain off excess water completely.
Grind the dals with the red chilies to a coarse batter. I keep some chana dal aside and add it to the batter in the end to get crunchy vadas after frying.
Heat oil for deep frying. Wet both your hands. Take a small lemon size batter and flatten it on the palm of your hand. Slip it very carefully into the hot oil. Fry till golden bowl and crisp.
Drain onto paper towel and serve hot with any chutney.