Dead cell in battery, replace it.
Cause it is shorted out ,replace it.
Yes, your can charge the battery with the radio on. But why would you want to do this? It will just take longer to charge with something drawing current from the battery.
The most common cause of automobile starting problems; is the battery needs to be charged. When the battery will not take a charge. It needs to be replaced.
take them out . you should charge battery then be ok.
It would depend on the condition of the battery.
If the alternator is good and the battery does not charge, then the battery may be bad. There could be problem with the electronics. You will need to take it to a place where they sell batteries. They have equipment to check out the battery and the wiring.
If you have already checked the connections on the battery I would suggest testing the alternator and the battery. If the battery will not take a charge or the alternator will not give a charge you could have similar problems.
Remove it and hook it up to a battery charger. If you don't have a battery charger, you can take it to Autozone and they will charge it for free. Just be careful handling the battery because battery acid can cause serious injuries and damage to property.
Do you mean charge by the vehicle running....or do you mean take a charge from a Bench charger? if its in the vehicle it could mean that either the battery/battery connection/cables, a faulty ground, or the alternator is defective. If its on a bench charger then the battery has a dead cell or is defective and needs replacing.
The battery may be defective and not able to take a charge.
Depends on how low of charge the battery is. I would guess around 6 hours on a dead battery. I suggest you use an automatic charger so you do not have to guess.
You would have to know the voltages of the battery and the UPS to know for sure. For example if the UPS' output is 120 volts, then it is capable of 5 amps of output. If the battery is also 120 volts, then it would take the UPS 29 hours to fully charge the battery. However if the battery was rated at 220 volts, then the UPS would never completely charge the battery. The source of the charging voltage must exceed the battery's voltage in order to fully charge it.