Power loss with plenty of battery

[Jimy2wheels]

I have a Nite Timber with the safe reciever, At about 12 + volts of battery the motor starts loosing power, surging, then acting like the battery is dead looses power and of course comes down.
the batteries are Admaral 2200 40c , I checked the resistance and that's OK, transmitter is a DX 6 that I buddy box with a DX 6. The ESC is the one that comes with the plane.. I'm wondering if this is an ESC problem. I have had the plane for a year , not problem till now.

[Joey L]

I had a similar problem with my AS3X and Safe equipped Carbon Cub. The plane would suddenly lose power within 30 seconds after take off and drop out of the sky with absolutely no control. After the first crash and repair I replaced the battery, after the second crash and repair I changed the ESC, Finally resolved the issue after the third crash by replacing the A3230 controller with an AR630 receiver. The plane now looks pretty beat up, but it flies great and I have not had another complete loss of control crash in over 4 months and 30 +/- fights. I have only added the typical newby dumb thumbs tip stall, and rough landing blemishes.