Putting an amp meter directly across a Lithium ion battery like this might be a bit dangerous. Depending on the meter they can produce nearly a dead short to a battery. Also batteries are rated in milliamp hours so simply putting an ammeter across one won’t tell you much except how much current it is capable of in a short burst. This would possibly be dangerous to the battery and to you! To measure milliamp hours (mah) you need to put a resistor across the battery with a value that will draw only a reasonable mah for that battery and then use a timer to see how long it lasts.