I have an '05 Honda Civic, and we thought the battery was gone. We jump started the car, and drove it home. We fully charged the battery, but it still doesn't start. Lights are funny, and while driving if I put on the radio and the high beams at the same time, they both turn off. What part of the electrical system / generator or alternator is likely the problem? How do I fix it? Thanks.

If your seeing 12 volts after the charge, it doesn't mean the battery is good,, a single cell thats bad in a battery will give you fits and produce the problems you listed,, remove the battery , and have it LOAD tested, that way you will get a true correct reading, a battery can show `12 volts, but a bad cell will not let it charge to the correct amps it needs to start the vehicle. once you've done that , and your sure you have a good battery ,, start the vehicle,, ( make sure that when you replaced the battery , that all the connections are clean and tight) with a meter, place one lead on each battery terminal, you should get a reading between 13.5 and 14.5 volts, if you do , then your alternator is doing its job, if not,, replace the alternator, ( your vehicle doesn't have a generator)