Lithium Powered Pocket Radio

This radio runs on 2 AAA batteries
It has a slim and compact design with a big Backlit LCD. Unfortunately, battery life is not that great due to the AAAs.

Battery current drain figures are:
60 uA on standby (good)
6.5mA backlit
42mA at vol 10
50mA at vol 20
100mA at vol 30 max

Normal alkaline batteries last about 2 months. Rechargeable NiMH batteries last about 1 month. Although it has a USB power port, it does not recharge the NiMH batteries.

This instructable was my attempt to use the existing USB port to charge a piggy backed Lithium Ion battery for convenient extended battery life.

Tp4056 board
Lithium ion phone battery
Soldering iron

The radio pcb has 3v3 regulator which takes 5v in from the usb port. This is a convenient point to take 5v supply to the tp4056 board pads adjacent to the usb port.

The tp4056 connects to the lithium battery, and the output voltage is wired via a 1n4007 voltage drop diode to the existing battery terminals.
The diode drops tbe max 4.2v by 0.6v to 3.6v for the radio.

Use Hot glue to piggy back the battery to the rear case, ensuring battery terminal wires are secure and well insulated.

i have been using this radio daily for the past year. A single charge now lasts well over 6 months.

The onboard usb charging port is so convenient.

Because of the lithium protection board, the battery charge indicator stays full, so cant be relied upon as it cuts out at about 3.7v.