RE: Lets hear about your Thunder Tiger Neptune SB-1.
I found that mine turns on the surface feature at around 8.5 volts,I have found also that there is an adjustment pot to increase or decrease the cut in voltage or trigger for the voltage monitoring system .It is he green pot just bellow the 2 mini sensor plugs upper righthand corner of thee PCB.I am not sure yet if the PSI cut off for the pump is also affected so check that it is not affected,I just found this out so check that the pump turns off when it should or the bag can explode uupps!
I had to find the lower cut off point since I use now Lipos to 7 or so volts which take a hell of a long time to get that low even with all the extra stuff on my sub not to mention dual motors!
If your getting wierd behavior at failsafe check each and every servo I had one bad servo with the 10 channels and corrected it right away.
Dave