My longest battery life lasted 4 years and 11 months, and the battery could still start my car. The climate here ranges from very hot summers to very cold winters.

I only replaced it because it was tested as bad but it could still start the car normally. I changed the original OEM battery to Kirkland Battery (now a year and a half with no issues and still tests good.)

I've also started my car with less than 11 volts so I believe you should be okay.

 

0.14A of draw when the car is off is not that much really.

Is it draining your battery to the point you can't start the car? How long does it take?

 

...my car's battery won't last 2 weeks just sitting there. I had to get a battery tender to keep it from drained out

 

issue resolved. it was (coincidentally) the battery. i took it to autozone and they said it was bad because it wouldnt take a full charge. i put the battery in last night and the car started up faster than i'd ever seen before - my battery was obviously not running at full capacity the past few years. autozone told me the battery was the original that came with the car in 2008..so its been going 5+ years.

it is just strange that it got to the point to where i could not start the car & the battery started losing juice at the same time that i reinstalled my passenger car seat. my only guess is that me having the car door open while working in the car depleted the battery and it was never able to charge past that point again

so for clarification, .14A (140 milliamps) draw is normal for the first 20 - 30 minutes. after that it should drop to around .030A (30 milliamps)

 

I also have 04 coupe not starting after sitting idle for 3 or more days. I have minimal tech knowledge. This started in last 6 months. Battery replaced, still happening. Local shop can't figure out where the draw is coming from. Thinking of going to infiniti service. Any suggestions?

 

if possible, get a multi meter and do the procedure discussed here. You'll need a multimeter, be able to connect it to the battery, and pull fuses while looking at the meter. If you check out this video that should be all you need:
just keep in mind your normal amp draw at first may be higher than 50ma like this guy is saying. mine was 140ma but after a few minutes dropped to before 50ma. this was because something in my car was staying on, by design. if your car stays over 50ma for more than an hour or two, something is probably wrong.

 

Parasitic battery drain was a big problem with many early G35s including my own and my niece's '03 sedans. There was a problem with the audio/hvac unit shorting out. You had to replace the entire very expensive unit with no guarantee it wouldn't happen again. Bad design and it typically failed out of warranty.

Battery drain is very frustrating. I owned a Blazer long ago with the problem as well. Also caused by the radio/CD player. I recently replaced the battery in my '07 sedan and was surprised at how many circuits are connected directly to the positive battery terminal. I guess modern cars need a lot of non-volatile controls and memory. Its a wonder they aren't putting deep cycle marine batteries in cars these days. Maybe that's the answer.

 

I’ve tried the suggestion of trying to find the part/device that is draining my battery by going through the steps I’ve found online. The problem is when I hook my multimeter up to my battery post and terminal the car horn keeps beeping off & on and the reading on the meter fluctuates wildly up and down so I can’t get an accurate sense of what the amp drainage is.

Does anyone have an idea of what I’m doing wrong? Thanks!

 

When you get it hooked up you need to use your fob to UNLOCK the car to turn off the security system.

 

My car registers 0.140 AMP from my battery in sleep mode
If I then remove the ROOM LAMP fuse (10AMP) of the inside fuse box, it drop to 0.070 AMP. I've changed all of the interior bulbs to LED and I still have the problem. What else does the room lamp fuse control?

 

Make sure that the door sill lights are actually turning off, the ones that aim down towards the ground when the door is open.

Usually if it's stuck on you will still be able to see a tiny bit of light shining inside the cabin at the bottom of the door.

 

Did you, or anyone ever figure out the cause? I have the same exact issue. My car does eventually drop to 30mA, but it takes 30 min after everything goes to sleep. This car has eaten a battery every 2 years since I bought it. I just feel like it's caused by this 140mA draw for 30 min every time I park the car. Not to mention, the headlights stay on way longer than necessary after getting out. Chasing my tail here.

 

How long exactly are your headlights on? Should be 60 seconds stock I think but the V36 chassis you can change it from the settings menu. V35 chassis the dealership has to change the setting in the BCM via Consult - II and it's available either OFF or in 30 second intervals up to 3 minutes on.

Regardless, the headlight delay timer isn't what's causing parasitic drain, I'd start with anything aftermarket, including stuff plugged into your power sockets because 99% of all parasitic draw I've seen was something sucking power out of a socket forcing the car to not hibernate until it's run for 30-60 minutes when the hibernate timer finally trips. There's an electrical load switch monitored by the car and if there is a power load still running from accessory power plugs it will keep the car on until it's predetermined hibernate timer has elapsed.

Another main reason for battery drain is simply not driving the car regularly enough, any car that sits for 3 or more weeks regularly should be on a trickle charger.

Aftermarket wired electronics like alarms, remote start units, amplifiers, head units, etc can all be problematic too. As these things age they might fail and never turn off, especially amplifiers since they are typically wired directly to a battery therefor not even controlled by the car hibernate timer.

The V35 chassis cars had problematic CD disc changers that would get stuck on and cause parasitic drain, the V36 chassis didn't have this issue though.

EDIT: Another problem spot can be the trunk and hood lights. However you would typically know the switch was on because I think you can't arm the alarm if the hood switch or trunk switch is open. However if your trunk wiring harness is broken and shorted out against something like the interior lamp wiring then it will just suck power continuously. You can lay down the rear seat, arm the security alarm, look in the window and see if the trunk light is on through the window. Hood is a little easier since you can just look between the cowl and hood and night to see if the engine bay is illuminated.

 

So, after chasing my tail several times on this issue, it ended up being something I was overlooking. I checked the charging system several times, but never hot. Today was pretty hot here in Kansas and found that my alternator was not charging after the car is good & warm. So, it was doing this intermittently whenever it would get to a certain temperature. Which would explain slow cranks after long drives and then letting it sit. My parasitic draw ended up being within spec. I will chase down the headlight time out issue today after I get this alternator swapped out. This doesn't look like a fun job at all. Thanks for all the ideas.

 

EDIT: Oops, you have a V36 car, I've only done one alternator on those so I'm not quite as familiar but iirc I took off the oil filter for better access as well as all the stuff in in the rest of the post pertaining to the V35 chassis. There might have been two oil sensors? One for temp and one for pressure?? Been a couple years so I can't remember.

The alternator isn't terrible, it's pretty tight under the car but an angle head pair of needle nose pliers helps to get the harness off. The job is 5x times easier if you remove the radiator fans which gives MUCH more room to work in front of it, those come out really easy too. Also there's an oil pressure or temp switch right next to it you'll probably want to unhook as well and it's clipped onto the alternator bracket a couple times.

The hardest part is those electrical harnesses on the alternator, fans, and the oil sensor. That's where the 45 degree angle head needle nose pliers absolutely save the day. Use them to hold down the release tab on the harness while you pop it off with your other hand, otherwise you WILL be fighting those things trying to get the release tabs held down.