UPS for Wifi Router DIY in just 3$ only

UPS for Wifi Router DIY in just 3$ only This video is a step by step instruction on making a low cost 12V/9V UPS for wifi router. Compared to 220/110V traditional UPS , this is cost effective & power efficient. Bill Of Materials : 1.Where can I buy this 9V/12V Router UPS Board ? 3.7$ Updated https://s.click.aliexpress.com/e/_AqKpMm 2.Where can I buy 5.5mm x 2.1mm Male Female Plug? https://s.click.aliexpress.com/e/_DBd2NvF 3.where can I buy 18650 3.7V 2400mAh Rechargeable Lithium Battery? Importing battery would be bit costlier ,So choose a local supplier who can give you the best price. http://s.click.aliexpress.com/e/_c25S7u 4.where can I buy 18650 Battery Holder? https://s.click.aliexpress.com/e/_DeT5VDb Datasheets of the 3 chips: SY6952 - Charging chip - Stepdown converter https://www.dianyuan.com/upload/community/2014/02/14/1392349590-86218.pdf XB8089 - Overcharge,Overdischarge,Short Circuit Protection https://datasheet.lcsc.com/szlcsc/1811180135_XySemi-XB8089D_C79928.pdf XR2681 - DC -DC Stepup Converter http://www.baitaishengshi.com/uploadfile/2017/1213/20171213103747.pdf