Assume Yi outdoor camera power consumption is 4w.
Means for 24 hours it will take 24 x 4 = 96wh.

To store 96wh in a 12v battery you will need 96/12 = 8ah.
You need minimum 12v 8ah battery.

To fully charge that battery in daylight. Base on Malaysia's typical 3.5h sun hour you need 96 / 3.5 = 12v 25.4w panel.

Summary:
Give or take some efficiency loss so you need to oversize a bit, You will need
1 x 18v 30W solar panel
1 x 12v 10A pwm solar controller with usb output for your camera.
1 x 12v 20AH deep discharge lead acid battery

Price you can go lazada check.

Good luck.

This post has been edited by yushin: Jul 10 2019, 08:28 PM

Well, 5V 20,000mah power bank should be able to last a full day but not sure TS want to charge and replace powerbank everyday or not.

if the powerbank supports charge and discharge on the same time, TS can consider solar panel that can direct charge powerbank through USB.

The circuit board that convert 12v from panel to usb does exists.

This post has been edited by yushin: Jul 11 2019, 03:46 PM