snkpkp

I installed a new battery in my 03 RX8 about a month ago, and for the last 8 days I didnt start the vehicle as my metering pump is out and I was waiting for the part. I went to start the car today, and click click click, no juice in the battery. took help from another battery and started, and now seems ok. My question is, is the way an RX8 would always work like if not started for more than a few days? I havent used the car at all and all lights and switches are off in the car...any clues?

Go48

What were the specs on the new battery? Are you sure it was fully charged?

Check a couple of things. Open the pass-through in the back seat area and check to see if the trunk light is on with the trunk lid closed. That has been a problem with some cars.

Also, there has been at least one case where a Nav system was not completely shutting down when the car was turned off thereby draining the battery over a few day period. Fully charge the battery and if it still dies after a few days you have an unusually large drain on it that will require troubleshooting with a multi-meter.

EDIT: Go here for a thread on the NAV problem:
https://www.rx8club.com/showthread.p...ht=power+drain

To check for the dark current drain with everything shut down do the following:

"To carefully check battery drain a good ammeter is needed. The range ought to be 10 amps, min. I use a digital multimeter with LED display. It has a special red socket to move the red lead into for measuring current.

It requires connecting so the current flows through the meter. In other words remove a battery cable at the terminal (either one, not both) and connect one lead of the meter to the battery terminal and the other to the cable. Be careful not to, say, create excessive draw above the rating of the ammeter like when trying to start the engine.

With all lights and ignition off the reading on the meter will now be the steady drain taken by standby accessories such as radio, clock, security alarm, GPS etc." (Quote prbeswick PM)

The dark power drain (I believe Mazda calls it "backup power" or "standard power") should be no more than about 20mA.

MPG > HP

I need to always remember to disconnect my battery or put it on a trickle charge, if I plan on not starting the car after 3 days. By the 4th day it just won't start. I imagined that it was due to the alarm system drain (also have LoJack - maybe it was installed improperly?), but per Go48, could I have a defect somewhere? The dealer says the battery is fine. I was thinking about getting a different battery, but haven't had a chance to look into it. Seems like the battery size is real important in order to ensure adequate air circulation on hot days. Anyone have suggestions on longer lasting (higher amp) batteries that fit the RX-8?

jdzoom8

Could be a bad battery, but it could be a drain on your battery, just need to determine the source. Troubleshoot as shown below:

Parasitic (or key off) drain is the cumulative load produced by electrical devices, for example, clocks, computers, alarms, etc., that operate after the engine is stopped and the ignition key has been switched off. Parasitic loads typically run 20 to 120 milliamps. Glove box, trunk, and under hood lights that do not automatically turn off when the door is closed and shorted diodes in alternators are the most common offenders. Cooling fans, power seat belt retractors, radios and dome lights left on, alarm systems, and electric car antennas have also caused batteries to drain. Leaving your headlights on will generally discharge a fully charged battery, with 90 minutes of Reserve Capacity [36 ampere hours], within a couple of hours.

There are two methods that are commonly used to test the parasitic load without the engine running, underhood light disconnected and the car doors closed:

10.1. Connect a 12-volt bulb in series between the negative battery cable terminal clamp and the negative battery terminal. If the bulb glows brightly, then start removing fuses one-at-a-time until the offending electrical component is identified.

10.2. A better approach is to use a DC amp meter inserted in series with the negative battery terminal. Starting with the highest scale, determine the current load. If the load is above 120 milliamps, then start removing fuses one-at-a-time until the offending electrical component is identified.

Go48

MPG>HP: See my edited post above for suggestions on how to check for an unusually high dark current drain. If your battery dies in 4 days, you have a major current drain with the car shut down. You'll have to go through a troubleshooting procedure where you check the current drain as you selectively remove fuses one at a time to find the culprit system.

snkpkp

thanks fellas. will update on that tomorrow.

Winfree

There are a lot of stupid things that drain the battery - like not getting the car to beep after locking it - so that some minor security systems and lights remain on - also as mentioned the trunk lights, that little flashing key etc. etc. I solved the problem by getting a little portable 12 V charger from Walmart - just make sure you link the cables properly but then you can put away your worries - also good if you have to start on a real cold day. I figured these were intended for the track and your pit crew would always do stuff like check batteries, tire pressure, oil etc. just before you start. The servant problem is terrible!

rxeightr

I've had my RX-8 sit for 3 weeks at times without issue.

Listen to what the others have said.

snkpkp

Battery is ok, powerdrain was not found, everything is in order, however i did lock unlock the car a few times and left the door open to clean the car a few times, which might have caused the drain. But who knows.....but MOP is fixed. thats all that matters.

Go48

So I assume you checked the dark power drain? What was it?

If a fully-charged battery goes dead within 8 days there is a big power drain. Keeping the door open for a few minutes or hours even, won't cause a good, fully-charged battery to die.

snkpkp

Brice-RX8

If it is the stock Panasonic battery like I used to have it only took 3 days for it to drain itself. Not had a problem since installing the Interstate battery.

Spin9k

If you notice, when you leave the car doors open, after a bit the interior lights all go out. Nice feature so as not to run the battery down. So simply opening doors is not what drained it.

Just a thought, I've accidently unlocked the trunk, and not noticing, the light is on...or leaving an overhead console light on, and these things obviously drain the battery. The trunk is hard to tell esp if it is just unlocked, not opened, if you're not looking carefully.

kwolfman

I had my battery drain once. It turns out my trunk lid was not completely closed. As a result, the trunk light was on, but I couldn't see it. Press down on the trunk and see if it clicks. You can also pull down the center passthrough and see if the light is still on.