Got my son a udi u12A helio, worked great for a bit, it died, so we put it on charger. But now it acts like it is completely dead. Could battery be messed up? Bad charger?
Put a multimeter on the charger and make sure power is going out.
Also check the helo on the bottom/side for a very teeny tiny switch.
I have one where the switch has to be flipped to charge even though the led indicates charge.