Quite a few possibilites. The two most likely are a scrap of insulating material is scraping the cover, or a wire. or you could have a bad bearing that is allowing contact of the stator and the rotor.
It could still be spokes, but that generally makes a sound you do recognise as spoke noise. At that level of overpowering, you could get spoke noise that won't go away unless you overtighten them, and don't do that. You are after all, putting a few hp into a bicycle wheel. My dirt bike wheel running 20s 40 amps always talks a bit, when I lean it hard into sharp turns trying to taco fold the rim. After a hard ride, It may ping and creak more than it did at the start of the ride, and I do have to keep re tightening that wheel every six months or so as I keep stretching out the spokes.
THE LIPO RULES. NEVER ABOVE 4.3V NEVER BELOW 2.7V DON'T PUNCTURE
Ideal charging /discharging range for Lipo, 3.65v minimum 4.1v maximum
See battery technology section, FAQ thread at the top of the page for lipo noob info.