Why does my phone show a yellow triangle and a battery dead signal?

[AC Question]

phone shows yellow triangle and battery dead signal

phone suddenly switched off and after putting on charge, battery percentage shows 0 and then screen blank. After sometime , phone vibrates and yellow triangle appear with dead battery signal...
i bought battery new maybe a month old

 

[B. Diddy]

Re: phone shows yellow triangle and battery dead signal

Welcome to Android Central! Which phone? Let it charge on a wall outlet for at least 4-6 hours, then try powering on again. If it still looks like that, then the battery was likely defective. Try a new battery.