Parasitic Battery Drain
 

So since because of the snow, I did not take out my car for 2 days. And I found out my car is now dead.

My battery is the Diehard Weatherhandler, which I purchased about 2 years ago. My car is installed with HIDs, Hella Supertone horn, both installed with a relay. It also has a Compustar alarm and side mirror tilt module, both installed both a professional.

This is actually not my first time noticing this problem and it only occurs at freezing temperatures.

Any thoughts?

Get a voltmeter and test how much is drawing. If it's acceptable, load test the battery.

Do this: How to Find a Parasitic Battery Drain: 9 Steps (with Pictures) but substitute for #5 for each of the devices you think.

"installed both a professional" honestly is a crap shoot in automotive world.

Car batteries get weaker during the extreme cold temperatures. Then factor in the current draw of the alarm/ECU etc.

DieHard batteries have never really been considered a good battery. What kind of vehicle is it? How many CCA is you current battery? Often times people do not drive their vehicles enough to truly charge the vehicles battery fully. So a battery tender is usually recommended.

It's a 2010 Mitsubishi Lancer. I thought Diehard are reliable lool but most batteries are rebranded. I am not sure if my alternator is failing...

I believe the CCA is around 640

put a voltmeter to it and see what the alternator is charging at.

its actually 550 CCA.

When I turn on my car, it goes up to 14.4V but after turning it off... voltage keeps dropping and below 12.6V...

So theres smt wrong

I did a current test and while the car was off, I had significant readings of current in amps. I heard one of the relay (my supertones horns) clicking while I disconnect and reconnect the ammeter.

So I guess that was my parasitic drain! fingers crossed, prob hooked up the relay wrong it came with no instructions and was from eBay... (China)

I think a good battery should be 13-13.2. Seems like it's not holding a full charge anymore or there's a drain. Again, testing for a drain is your first course of action.

welp driving with no horns now...