I've had my RX-8 since November '04. Recently, over last few months, if I leave my car sit for 3 days or so the battery dies. I took it to the dealer (Maple Shade Mazda) for the third time and for the third time they replaced the battery. The service guy told me the since I don't drive that often that I should have a trickle charger on it. I pretty much told him that he was out of his G-- Damn mind and that the next time this happens I'm getting a new car under NJ's lemon law. Has anyone else had this problem? I checked for a bad ground and to see if the regulator was over charging the battery. Any other suggestion?

 

My first suggestion is not to make duplicate posts in other forums.
Your other thread got little response because troubleshooting electrical problems is not easy to do so I doubt you going to get an answer to your problem here. But to start with the obvious have you added any aftermarket electrical equipment? Any damage to the car, even a minor event that could have just damaged some wiring? Jump-start it lately? Did this problem begin after getting it serviced? If the answer is no then the dealer will have to test for power drains from different parts of the car to try and track down the cause. In the meantime get a battery disconnect, that will at least make sure you do not get stuck someplace.

 

Not to state the obviouse but have you checked you trunk lid. I have found that it is really easy to leave the trunk partially open and the light never shuts off.

Just a thought

 

You need to do a current draw test as it seems as though you have a parasitic draw on your battery. Have you had anything done to your 8 at all? IE: car alarm, remote starter, audio upgrade? You may have a bad door pinswitch which on some cars will show 2.3 volts, over the course of 3 days this would be ample to drain a fully charged battery.

 

I thought I was going mad. I was sure I had replied in this thread???

Turns out, I have!!!

 

Scudrunner and I both have this same problem. Myne lasts 2-3 days. I have yet to figure out what it is. I've disconnected all the electronics in the car and it still dies. I measured the current draw with the car off, and it was negligible. I even upgraded to an Optima Yellow top battery. No help. I would love to know what the cause is.

 

sounds like your charging system, try a load test. faulty alternator that is not providing enough current will rapidly discharge as it provides the extra current to the electrical system, in effect current flows out of the battery to power the load but no current flows into the Battery to charge it.

 

I of course suspected the charging system was at fault. But, I tried disconnecting the battery and letting it sit, then reconnecting it right before I start it and its always fine. Its some kind of intermitent draw.