HID keyboard drains iPhone battery quickly

[Jeff]

I am connecting my development device acting as a BLE keyboard using HID over GATT and it seems to be draining the phone battery very quickly. Every 7 seconds I would get a pair of HID Suspend/Exit Suspend commands from the phone even when the phone screen is off and the keyboard is not sending any data. If I just connect using ANCS with my device I don't see the same power drain on the phone even when using the same BLE connection parameters. I saw this problem in iOS7 and it still continues in iOS8. Does anyone else see this issue? I cannot find any BLE keyboard products on the market to compare to.

ios8-hid.csv The attachment has the HID activity when the phone is idle. Handle 15 is the HID control point: developer.bluetooth.org/.../CharacteristicViewer.aspx

This is the frame data for the HID suspend/exit suspend commands. Frame 8,400: Len=27 ATT: Signature Present: No PDU Type is Command: Yes Opcode: Write Command Attribute Handle: 15 Unknown Attribute Data: 0x00

Frame 8,485: Len=27 ATT: Signature Present: No PDU Type is Command: Yes Opcode: Write Command Attribute Handle: 15 Unknown Attribute Data: 0x01

[Jeff]

The local device is a nRF51 using HID over GATT. I did not measure the nRF51 power, only the battery % on the phone side. With no keyboard activity and the phone screen always off, the phone battery drops from 100 to 85% in 14 hours. If I do not have the HID service enabled but only ANCS, the battery drops 5%. The only BLE traffic I see from HID is the constant Suspend/Exit Suspend from the phone. I cannot find any way to stop the phone from doing this.