I have a generic Newsmy P76 android tablet with a cracked screen. I'm thinking of using it as a battery pack. It is still working but the display is unreadable. It has OTG usb port and when connected to a phone, it charges the phone a short while before the tablet goes into sleep mode and turns off the usb.

It doesn't have usb debug mode turned on so I can't disable sleep mode using software tools. So I'm exploring whether I can do something on the hardware side.

I suppose in sleep mode, Android cuts off power supply to the usb port to conserve power. Is there any way to bypass this by cutting some wires or soldering some wires? 

I checked the specifications of the Newsmy P76 and the battery is 2600mAh 3.7V which is less than the 5V required by a usb port. Otherwise I suppose I can just solder a wire from the battery to the usb connector?