RE: Lets hear about your Thunder Tiger Neptune SB-1.
Hi Bryan it sounds like to me that the subs control board is not connected properly,go to the assembly / ownwers manual and check that all the connections are correct especialy the one to the pump or the pressure sensor,for it to shut down usualy means a bad connection or possible bad control board.
The battery should be charged with the right range of charger of no more than an amp for that battery.
Sometimes the assemblers make mistakes especialy witha machine as complex as this one so have some patience and corect ant problems .
Also if you need to get parts there inexpensive ,like the controlboard 27.00 bucks at RC Warehouse or a bit more at Tower Hobbies,use the part #s to look up parts in the first website.
I have had very good luck with mine right out of the box she was right on and ran like a swiss watch ,but I had to modify the hell out of it to get better performance and enhancements,but in its original form she is one great sub!!
Dave