Philippine Airlines (PAL) has updated its policy regarding power banks.

In a nutshell; (1) Passengers are limited to two power banks with a maximum capacity of 100Wh each. (2) You must have the power banks with you at all times, or under the seat—never in checked luggage or overhead bins. (3) While you may charge your devices, charging the power bank itself is strictly prohibited during the flight. (4) Ensure your device has a clear capacity label before heading to the gate.

Power Banks are not the only restricted items when flying via PAL, you can go here, for more information.