"Battery not fully charged"
When I shut off the charging plug of my mobile , before the mobile was fully charged, it showed
"battery not fully charged."
As far as basic grammar is concerned, this should have been "battery is not fully charged." Is that correct?
"Battery not fully charged," as you have accurately observed, is NOT a complete sentence, but it is not grammatically incorrect within the context. Titles are not complete sentences and this falls into that category. This kind of general statement, though, is not considered incorrect grammatically