Usually it means that the alternator isn't charging the battery. Batteries store electricity and the alternator uses energy from the engine to produce electrical energy for all of the devices in the vehicle and to recharge the battery. If the alternator isn't working the battery will eventually loose it's charge and you will not be able to start the vehicle.
the battery light means that your battery is being charged properly. so let it light.
Your battery is not being charged
That typically means that the alternator is not functioning.
alternator is not charging battery, or loose - corroded connection on battery cables
Your battery isn't being charged or accepting a charge
Your alternator is defective and not recharging the battery. Have the alternator checked.
The alternator is over or under charging.
most likely the alternator is bad.
There is problem with the charging system.
battery is loosing power, probably there is power thief
A low battery can cause the electrical system to flash check engine lights
It indicates that your battery is not being charged and that you need to have the electrical system checked.