Problems with car engine light coming on and off,after 2or 3 days i need to add another battery

Needs to be on a scanner to see which is failing. Best guess is bad wires/ plugs at the sensors.

To clarify what you said, sometimes the engine will crank but not start, or sometimes the engine will not crank ?
Makes a difference on what to troubleshoot.

There are some simple kits which have a glowing fluid which can be seen with a UV ultraviolet light supplied in the kit.

You add the glowing liquid to the engine, run the motor, and inspect the drips for the leak location. Then you fix that bad part.

Now sometimes the sending units do leak. But any gasket or seal can leak just as well.

Do not run the engine with the oil light on. Check your oil level constantly. No oil=no engine.

Can not speculate on battery problem from info provided.

The Battery CCA Rating is to turn over the starter

CCA--Cold Cranking Amps
That is at zero degrees
Total cranking amps is at 32 degrees

The car runs off the alternator
It puts out over 14 volts

The 12 volt battery is 6 cells @1.2 v each = 13.2 v

You need 12.6 volts to test a car or you charge it first

You need over 13 volts to charge a battery,thus the alternator

The only other job the battery has is a stabilizer in the electrical
circuit

So you need to have the charging system diagnosed as the
various light you have on should be off when engine first starts

take the car to a part store they will run a scan for free

The light you describe is not a pilot light, this is an indicator that the battery is not being charged (It comes on when you first turn on the ignition, before you start the engine because at that stage, without the engine running, the battery is not being charged. Its being on when the engine running is a warning that you have a fault).

Hence, the reason the battery was flat after the journey is because you used the power in the battery to run the engine, illuminate lights and indicators etc.

Causes for the syetem not to charge the battery are usually 1 of 3 things.

The fan belt that drives the altenator has come off. This belt usually drives a fan or power steering or both, so if broken, you would probably have other problems. - Check that the belt is on and not slipping

There may be a fault in the wiring, so your altenator is not charging. Check the plug on the back of the altenator and check around the general vicinity for damaged or faulty wiring

Most likely cause is that the altenator has failed. It may be repairable or require replacement depending on the fault.

Please add a comment to this thread if you need further guidance.

the check engine light comes on for a problem to find out what problem you need to scan and read codes for example did you gas up and leave the car running this would code a p0440 evap system or the car runs rough you can have a p0300 misfire so you are asking if the transmission needs oil you would have to check the engine light is not design for that purpose so get it scanned or unplug the battery if you cant afford to test system and see if it comes back on

3 digits. follow this link for more info. Good Luck.
http://autorepair.about.com/library/ts/obd-i/bl-dtcs-98.htm

IF YOU RECENTLY UNHOOKED BATTERY OR HAD DEAD BATTERY THE COMPUTER WILL NEED TO RELEARN IDLE STRATEGY,START VEHICLE KEEP IT RUNNING AND DRIVES ON 2OR 3 MILE RUN SHOULD BE SUFFICIENT IF THIS DOESN,T WORK LOOK FOR VACUUM LEAKS IN ENGINE COMPARTMENT OR POSSIBLE BAD IDLE AIR CONTROL LOCATED NEAR THROTTLE BODY

Problem 1: buy a system heater to keep the engine warm at night.
You can buy them at any autoparts store . You take your pick from the variety.
Place a light 100 Watt Bulb near the battery but not too close to anything else where it might burn anything.

Problem 2. Check your coolant level to see if you have the proper level. Make sure you have 1/2 antifreeze and 1/2 water if you add any coolant /antifreeze and bleed the colant system. By running the car let it cool, then turn the radiator cap or turn the bleed screw provided on some cars near the thermostat outlet. Then adding some more water and coolant etc.The tightening the cap or bleed screw. When radiator is full. Check the radiator and and remove any debris that may be keeping the air out.

Problem 3. Will get fixed because your battery won't die.