-Ampere meter can only be connected to 5v input end of the module. 

-It is better that the charging current is 37% of the battery capacity. If you charge to the battery of 1000mAH, current of 400 is enough. 

-The connection wire should not be too thick. 

-Make sure the connect point is good. 

-If the input voltage is too high, like 5.2v, the current will be less than 1000mA, it is normal. It is protection function, auto-substract the charging current to avoid burn damage to chip. 

-NO reverse polarity.

Package includes:

1x Charging module