Connect BDESC S10E RTR
The slow red blinking is the voltage protection. https://static.rcgroups.net/forums/attachments/5/9/5/6/0/2/a7824090-71-ESC.png

I tried to hook it up to a 18V Li-Ion Battery Pack from a Drill and had the same problem, unfortunately it got not only a untervoltage, instead it got some overvoltage protection too. The BEC that delivers 5V is from the volatgeprotection unrelated, so servos are still working.

After i hooked it up to a 2s Lipo (7.4V) (8.4V fully charged). It started up and works.

If I start it up without a reciver attached to it to give him a position/speed signal it blinkes the same way red.

And it blinks red when I start it up in a postion/speed state that is not neutral, till it gets his neutral(0 speed). Neutral is something like a 1,5ms pulse, from what i read from wikipedia. https://en.wikipedia.org/wiki/Servo_control

So there are two things to try out, decrease the voltage to something like 10v and try if it solved it. Or check how you are sending you speed value to the controller and if you have sent a neutral speed at the beginning.

Hope that helps a bit, even it the answer is quite late.