ds_usb_input_report.txt

USB

0 Report ID 1 (0x01)
1 LX (0-255)
2 LY (0-255)
3 RX (0-255)
4 RY (0-255)
5 L2 (0-255)
6 R2 (0-255)
7 Frame Counter (Increment by 1 per poll)
8 DPad (0-7 clockwise, 8 default), Square (16), Cross (32), Circle (64), Triangle (128)
9 L1 (1), R1 (2), L2Btn (4), R2Btn (8), Create (16), Options (32), L3 (64), R3 (128)
10 PS (1), TP Click (2) , Mute (4)
11 ???? (Always 0 for me)
12-15 Counter? (Increment by 1 per poll)
16-17 Gyro Pitch
18-19 Gyro Yaw
20-21 Gyro Roll
22-23 Accel X
24-25 Accel Y
26-27 Accel Z
28-31 ???? (Seems to increment by ~12000 per poll)
32 Battery? (15 max?)
33 Touch 1 ID (&0x7f)
34-36 Touch 1 Coordinates
37 Touch 2 ID (&0x7f)
38-40 Touch 2 Coordinates
41 Touch Packet Counter
42 ???? (Always 9 for me)
43 ???? (Always 9 for me)

44-48 ???? (Always 0 for me)

49-52 Counter? (Seems to increment by ~12000 per poll)

53 Extension? Battery (0-10), Charging (16), Fully Charged (32)
54 Extension? Audio L? (1), Audio R? (2),  Charging (8)
55 Extension? Mic? (1)

56-63 ????

12-14 timestamp
16-17 Accel X
18-19 Accel Y
20-21 Accel Z
22-23 Gyro Z
24-25 Gyro Y
26-27 Gyro X
41 Touch duration? (goes crazy when you touch)
49-52 another timestamp
53 Battery charging (0x10)
(not so sure about gyro XYZ, maybe the order is wrong, I couldn't figure it out)

I couldn't find any information about total battery.
BT seems to have the same with +1.

32 Mine goes up to 17, it chances every time I plug in to computer so properly not battery.
52 goes up by 1 about every 5 second.
53 seems like battery from 1~10. Mine goes up to 42.