Newbie here. Just started enjoying my Big Rock and with an Admiral 2S 5000mah battery running through my lawn I get 15 min runtime. I purchased 2 Povway 3S 5200mah batteries and I only get 7 minutes. So I returned them, and bought Goldbat 3S 5200mah batteries and I got 10 minutes before they quit. When I put them on my charger, it said they were at 4.16v per cell. Why are they cutting out early? I have only balanced charged them. I have discharged and recharged them and still the same issue. I am using a Dynamte passport ultra P2 Charger. Any input would be appreciated. Could there be an issue with the esc?