Multimeter Upgrade on Li-ion Battery With Charging From USB

How do i upgrade a multimeter

Step 1: All the Things You Need

• Li-ion battery. 18650:

http://ali.pub/22bdhq or http://ali.pub/22bdjo . Other sizes: http://ali.pub/22bdmz or http://ali.pub/22bdnk

• DC-DC step up converter: http://ali.pub/2206yd
• BMS: http://ali.pub/220756
• Charging board with protection: http://ali.pub/22be3p or without protection: http://ali.pub/22be3p

Step 2: If You Use a Charging Board With Protection, Use This Picture.

Step 3: Without Protection Will Look Like This.

Step 4:

Now you can throw away the 9-volt battery.