I have an 03 coupe with a year old battery in it. About 6 months ago, I went on a trip where my car was not driven in 2 weeks, came home and the battery was dead. That was fine, I bought a portable jump starter and jumped it up and had it running. But ever since, everytime I dont drive my car for 1-2 weeks my battery dies and I have to charge it up everytime I want to drive it(i dont get to drive it often since I work and go to school).

Heres the bad part, I charged my battery 2 days ago since I expected it not to start since I stored it in my garage for over a month due to the winter. I drove it for a good 30 minutes on the highway, ran my errands and put it back in the garage. Now one day later, the battery is dead again. Im getting tired of using my battery charger every time to start this thing.. What should I do?

Sorry for the long text, just looking for some advice

 

my understanding is once the batter goes under 12 volts for watever the battery is not the same anymore and needs to be replaced. since urs is 6 months old if you still have the receipt it should be under warranty. if not replace anyway and this time keep the reciept and see if it happens again

 

Anytime your battery "dies" you should be recharging it fully with a plug in charger with a desulphation mode. Don't rely on the alternator to fully charge it since it's not meant for that and doesn't do pulse charge to break up the sulphation.

Did you buy a cheap battery? It may just be a low capacity battery or maybe has a bad cell.

Do you gave an aftermarket alarm in your car?

 

Could have a bad audio unit that works fine but is pulling a heavy current draw while car is not running. Very common in the V35 models. Try removing the radio fuse next time you park it and see if battery still goes dead. Fuse is in the little box directly in front of the battery.

 

Bad battery or a drain in the circuit.

If you bought a cheaper battery with a low rating, or just a cheap brand. Sometimes cold weather can expedite the battery drain, but not as fast if you have it stored in an enclosed garage.

Find that receipt and get a fresh battery under warranty. Most batteries carry at least a 1yr free replacement or more. They also do battery testing for free in most shops, and if they find that its not holding charge, you will get a new battery.

 

Once a battery is drained, it's never the same again. I usually replace at this point.

However, I'd search for a drain. To do this, you need a digital multimeter that has the ability to read amps in DC current up to 10A. Not all of them do this.

You disconnect one lead from the battery and hook the meter up in series with one lead on the battery post and the other on the lead.

I don't know draw of a normal G35, but I'd imagine it's significantly under 1A...perhaps even under 1/2A. For the battery to drain in days like that, I'm guessing there might be a draw of 1A or higher.

If you do see this, start pulling fuses to isolate which circuit the drain is from and then troubleshoot from there.

If the draw is low, then get a new battery...preferably a better one.

 

Anything around 50 milliamps or less is acceptable. When you first hook multi-meter up it will read high until the BCM goes to sleep. Normally takes about 20 minutes for BCM to go to sleep. Then you will get the proper reading to see what your current draw is exactly. Hope this helps guys.

 

A weak or dead cell in your battery

Purchase a battery hydrometer to test the individual cells



What was the CCA rating of the battery that you installed 6 months ago?

If you purchase a new battery get one with a 700-900 CCA rating

Telcoman