power start at e10, and decay every tick battery is 10*log(power)% example: e10 power: 100% e9 power: 90% e8: 80% e7: 70% e6: 60% ... e3 (1000): 30% e2 (100): 20% e1 (10): 10% 1 (e0): (-)0% 0.1 (e-1): -10% 0.01 (e-2): -20% ... e-6: -60% e-7: -70% e-8: -80% e-9: -90% e-10: -100% ...