Pressure cooking blackgram lentils with enough water is very important. I have used 1 cup of water to cook them that is when I could get soft and completely cooked lentils.
When you grind the cooked lentils the batter should be of pouring consistency. Adjust water accordingly.
If you use less water to cook and grind lentils, the pakoda drinks lot of oil.
Add rice powder little by little to avoid disaster. Because based on the quality of black gram lentils, it requires little less or more rice powder.
I had to use extra 1/4 cup of rice powder for the stiff dough.
You can substitute green chilly by red chilly powder too.
In an air tight container ribbon pakoda lasts more than a fortnight.
To check oil temperature, drop a pinch of dough in to oil. If it raises to the top then oil is rightly heated up. If the dough settles down or slowly raises then you need to heat oil for some more time.
Always deep fry the pakoda in medium flame for better results.