Why does my axon ZTE 7 mini have a + in the battery icon?

[Android Central Question]

On my ZTE 7 mini my battery icon has a + and the top bar is orange. This happens even though I do not have my battery saver on. This happens every time my battery goes under 15%.

 

[methodman89]

1st, stop draining the battery so low. 2nd, did you read the manual? It should have the meaning of the plus sign.