Something is draining my battery down...first the radio stop working and now my battery is low...The battery is new so I don't know what is going on...help me please I also had the alternator replace as well

The radio fuse is in the fuse panel inside under the left side of the dash. It is marked on the fuse cover as Radio, clock. If the battery drains down fast, like overnight there is another problem, sometimes aftermarket alarm systems will drain the battery down. Check for any lights that may be staying on like the stop lights or interior lights.

Try giving the vehicle a boost. Were the interior lights/ignition on during radio replacement? The battery may have run down. Even though a new battery, with accessories left on, it will drain causing the low voltage display

if this is a what I refer to as newer model vehicles 93 to 95 and up if you disconnect the battery cable while it is running it kills power to the computer and the car will shut down, it can also fry the computer. That is something that you could do a really long time ago, but now can cause expensive damage. I would suggest taking car to Auto Zone or Advance. let them check the battery and alternator even though they are new.. I cant tell you how many new alternators fresh out of the box I have installed and were defective. same can go for batteries they sometimes can sit on a shelf 6 months before being sold and can start to break down and they will not hold a charge. if they both test ok. you need to check for a parasitic drain. I believe Auto Zone will do that for you for free like the battery and alternator test. if not take a multi meter,,put leads on battery and see if voltage is slowly dropping over a period of an hour or two. then you can start removing fuses one by one and see if voltage drop stops.. if say radio fuse stops it,, you know there is a short or problem with the radio,,

It could be a faulty alternator. This would cause a battery drain since the alternator would not be recharging the battery and supplying operating voltage to the vehicle. Once the battery dropped to about 8 volts then the gauges, A/C, radio and other electronics would start acting crazy. Eventually the car would have shut down, but since you stopped at the post office, that didn't happen. With the battery being so low in charge, that would not allow the car to restart, as there would not be enough current to engage the starter properly. Check the battery voltage. If it seems ok (12-13 volts), try checking it again with someone trying to start the car. A normal battery will see some voltage drop, but a drained one will fall to almost zero with a starter load. Since you have gauges and not warning lights, a discharging battery may have gone unnoticed. If you determine the alternator is bad, be sure to have the battery charged, or if necessary, replaced before using the new alternator. A low battery can cause a new alternator to fail and most alternator warranties will not cover this type of failure.

i would recommend performing or telling your tech to perform a parasidic drain test. because if your battery is dying after a day of no use it sounds like a control module is telling something to turn on when not suppose to and is draining the battery so you will not be able to start it.
hope this helps

As with any battery drain, you would pull the fuses and disconnect the major circuits while watching a test light or meter that is showing the drain. When you find the circuit in question the light goes off.
Then the fun begins trying to find the source of the drain. In your case you may want to start with disconnecting the radio. You may need a shop manual to get the wiring diagrams.

Check alternator voltage output, might be low. obd2 scanner

You can run your radio a number of days and will not run the battery way down. I had a car that did that and each night when I shut the car off I disconnected one fuse and did that till the battery did not run down. It took several times and I would write down the fuse I pulled. I found something was malfunctioning in my air conditioning switch area. My mechanic replaced something and is ok now. Not saying that is your problem.

FIRST, has anything been changed recently, or added to this car? A friend had a similar thing happen to her dad, and they discovered a new alarm system was sucking his battery dry. How old is the starter? did you have it checked out by a reputable technician? A bad armature can wreck a battery in no-time. Same with an alternator, although it is more rare.
This is where you need ultimate patience and a battle plan.
Big picture: The sytem leaks power when the key is off.
Little Pictures: Eliminate circuit-by circuit.
Make a plan on paper of the various fuse circuits in the car.
Actually make an outline, 1,2,3, A,B,C, a,b,c to map where you are and where you have to go.
Make note of the critical ones, start with the larger circuits and work your way down by pulling each fuse and seeing if the drain stops. A quicker way would be with a meter, but most people don't have one or know how to use it. What you're looking for is a drain on the system, and frankly that is very tough.
But if you eliminate each circuit, one by one, you may well hit paydirt.
Once you have narrowed it down to a circuit, then look at what that circuit is powering ( windows, radio, alarm, etc) and unplug each in turn...
I said you should be patient. Something is sucking power from your battery while you are sleeping and you have to narrow it down logically and with some scientific certainty. This is a tough project, but an automotive electrician will work in a similar way and charge you big bucks to do the same thing.

An alternator going bad will drain your battery in a few hours of driving, and it will not recover. A battery going bad might give some trouble starting the car, but once under way, it will recharge, and work for many weeks until it finally dies. A bad connection on the 2 power cables to radio (ignition & live battery) will trip the corresponding fuse, so that is not the problem. You might have bad speaker connections, and it will sound like you describe, but it will NOT drain the battery. My best advice is 1) Disconnect the radio for a day or so, and see if the condition improves. 2) With a voltmeter, test the battery voltage just after shutting down the car. It should read 13-14 volts. Then test it one hour after that, and it should read 12-13 volts. Should voltage read below 12, then you have either an accessory draining the battery, or a short circuit.