I ran mine on 3s yesterday with ambient temps in the 40's and had the esc thermal on me. Running was with stock gearing, in grass, low dead grass, and I've had the esc get hot (not thermal) running 3s on pavement too. I read someone added a Novak cap and it helped the cogging and ran a little cooler, but seems a gearing adjustment is needed for 3s with stock esc.