30%. At 20% the power drops dramatically. I found this out thinking the power level would gradually come down. I panicked because of all of the sudden it was 10% then 5% and the warning came on and do a RTH but I tried to manually bring it back but the power drop and landed. I lost sight of the Spark and later came to realize it landed on the water according to the map.Mine's set at 30% though that seems too high and now that I'm more experienced I feel I can bring the bird home quickly when power is running low. Where is yours set?