Battery dead after a day to two days of sitting . Battery new and chargeing at 14.2v at no load ./13 amps . Car is 1995 mistique with 40,000 origional miles but sits outside all the time . Any ideas ?? Thanks .

replace ignition switch.

try using a volt meter after you shut it off and watch the meter and see if it drains,which would mean something is still drawing power when the car is off,then try removing fuses one at a time too possibly narrow down where the draw s coming from.if the battery is new then it should not have a bad cell which could cause it too drain.

sound like alternator has bad diode allowing battery discharge

Your alternator is bad that recharge the battery as you drive

Sounds like you have a toasted battery or alternator. Have you performed a load test on the battery? Have you tried to charge the battery? First remove the battery and charge it externally from the vehicle. If the battery won't hold a charge, or won't hold a charge of 12 volts, replace it. Once you have the vehicle started, test the operation of the alternator. It should be putting out at least 13 volts back to the battery to keep it charged - if it is putting less than 13 volts or more than 16 volts, replace the alternator.

altenators have to be running a 13.5 volt charge to be good

theres a draw somewhere. these are sometimes hard to pinpoint.start by checking that all lights turn off,glovebox underhood light all lights,you will need a meter to meter the draw amps, then with key off doors closed look at the draw amount,.02 to.03 is allowable, start removing fuses and watch if amps drop,one fuse at atime, start with this to try and pin down a location of the draw.hope this helps.

First of all, disconnect the negative cable from the battery and charge the battery up to a full charge. When that is done, check the battery voltage with a volt meter; you should see about 12.5 to 13.5 volts DC. Next, reconnect the negative battery cable and make sure all cables and connections are clean and tight at the battery and the starter. Start the car and check the voltage at the battery again with the car running. You should see about 13 to 14.5 volts DC which confirms that the alternator is doing it's job.
Next, check to see if your brake lights are on when no one is pushing on the brake. If they are on, then that is what's draining your battery.
If that is not the problem and your car battery continues to go dead after a couple of days of sitting, you have some sort of "parasitic load". You will probably need an automotive electrical expert to find the parasitic load.
If you find that the brake lights are on when no one is pushing on the brake, you most likely have a little plastic piece broken that mounts near the top of the brake pedal shaft. I believe it is called a "brake pedal stopper" and it is supposed to push against the brake light switch when there is no pressure applied to the brake pedal. When it breaks, you should find the remnants on the driver's floor area. You can get a new one from the dealer for a couple of bucks. You may want to use a flashlight to check things out near the top of the brake pedal shaft to see where the brake light switch is supposed to be pushed by the "stopper".
I hope this helps.
Good luck, Mark

Have the altenator checked.

that indicates a dead battery. Your alternator may have failed. Check the battery reserve power, and if it is under 8VDC the car will not have enough power to crank the starter. A healthy battery will be around 10-12VDC when the car is off.... and 13-14VDC while running.