hey everyone, i've read some other posts on here regarding this, but didn't find any w/a definitive resolution. i bought a 2004 8 in february of this year. it is the gt w/ nav. my battery dies if i don't drive the car for a coupleof days in a row, 4-5. something is obviously sucking the power out of the battery way too much when the car is not in use. i've actually had abiiger battery put in. went out oftown for 5 days, came backand battery was dead. they also had to put a new battery in before i took the car homefrom the dealer since the second timei went back to test drive the car, the battery was dead (first time it had to be jumped). i've got it at the dealer now and they toldme they have never heard of this problem. if they say there is nothing they can do about this, what would your next action be?

thanks in advacne

 

I have the same issue so I installed a battery tender. If the car is going to sit for over 3 or 4 days I just plug it in.

https://www.rx8club.com/showthread.p...battery+tender

 

Removing the lamp from the trunk light. Sometimes the trunk light switch is misadjusted and the light stays on with the trunk shut. You can check by removing the pass-through when the trunk is shut.

Other times people just don't close the trunk properly, or the kids play with the fob remote and pop it.

Gomez.

 

Disconnect battery.

 

The battery shouldn't drain that quickly. The car consumes what's called "dark current", used to keep computer memory alive. This is a fairly low current drain and should not exceed 20 milli-amps of current. At that rate, even a modest battery should be able to go 2 or 3 weeks and still retain enough power to start the car. The trunk light is exactly the kind of thing that could cause your battery to die in a couple of days. When I was replacing my trunk light with LEDs (because I have the spare tire which blocks the light), the oem trunk light pegged my current-meter at 250 milli-amps so it's probably a bit higher than that.

Fortunately, as Gomez pointed out, we have a simple trunk-light inspection port -- also known as the passthrough cover.

If it's not that, then you'll need some detective work to measure the actual dark-current consumption of the car. It's likely way over 20 ma, and will need to track down the source.

Keep in mind that conventional car batteries don't tolerate deep discharge very well. If you have drained the battery multiple times it has probably lost a good deal of its capacity.

For a dealership to say they've never heard of this kind of problem is utter horseshit. It might be the first RX-8 they've seen with this issue, but it happens to vehicles all the time.

 

thanks for the replies everyone. i have checked the trunk light via the pass through and it was not on. haven't heard from the dealer yet, so we'll see what they say. battery tenderis a greatidea, but i live in a townhome w/ no garage.

 

One other potential source of current leakage that is easy to check is the surface of the battery itself. If you have a non maintenance-free battery (the original is one of these), a small amount of battery electrolyte can mix with dust on the top of the battery and conduct a surprising amount of current between the posts even if it doesn't look all that dirty. And it's sneaky because it won't show up if you're just trying to measure dark current into the car's electrical system.

Make sure the top of the battery case is totally clean and dry.

 

Any aftermarket electrical goodies fitted?

 

The stock batterys are junk. I replaced mine and ended my dead battery problem.

 

I'm on my second stock battery,the first one died after two weeks in storage.
Next stop: Optima batteries.
I'm tired of the half-assed,Ford-inspired swill they've added to this car.
(The battery,the stock Ford Focus-grade 5w paper-coned JUNK speakers,and a low-powered
head unit amp-)
Next time,I'll be dealing with a car company that pays attention to DETAIL,something Mazda clearly lost sight of with the RX-8.