:confused: I was out of town on business for 3-1/2 months. My year-old RX-8 was under wraps. When I returned, the battery was dead. I mean DEAD. I talked to the Mazda service rep who told me that new cars these days have a "parasitic drain" due to all the on-board electronics and that I should install a battery terminal disconnect switch if I am going to leave the car parked for over a month. I stopped at several auto parts stores and did an internet search, all with no luck. Has anyone else had a dead battery problem after the car has not run for a month or more? Anyone have a line on a battery terminal shut-off switch?

If you go out of town often I would suggest a trickel charger so your car will be ready to go when you get back.

yes mine will kill the battery in about a week

trickel charge

Great. Thanks! What's a trickle charge? I have an old battery charger - do I leave it connected to the RX-8's battery the whole time I am gone? Or is this a new device I need to obtain?

Well if you can park the car outside this is an easy fix, or run the charger out a window.
http://www.baproducts.com/rpgt0417.htm

Or something like this if indoors
http://www.redhillgeneralstore.com/A53583.htm
http://www.carcareonline.com/detail.asp?product_id=29204

A battery disconnect switch looks something like this
http://www.prostreetonline.com/buy/summit_racing_battery_disconnect/

What the dealer told you is about right. Being involved in the automotive industry, there is a test that almost all the manufacturers use called "stand by mode" or other simmilar names. Pretty much is to let a test vehicle to sit for 21 to 30 days outside and after that they will try to start the car without any assistance. During this period they will monitor the current draw by the PCM, radio and other parasitic loads. Again that also depends on the conditon of the battery and the enviroment. The mentioned trickle charges will work. However, If I go for a business trip longer than a month, I rather disconnect the battery. Upon returning it I will give it a few hours of charge before starting the vehicle.

This is the device that I use for those times that I leave the car at the airport for a week (alas). It's cheap too: http://www.autosportcatalog.com/index.cfm?fa=p&pid=53 ... "the green knob." It's weird, but after a week, my battery is fine, even with the knob in (tried it at home). Aside from that, I like the peace of mind.

If you want the "RX-8" of battery protection devices ( ;-) ) , then check out: http://www.autosportcatalog.com/index.cfm?fa=p&pid=141 .

very good eye.. I am going to carry that stuff.. All 3 the battery tneder is goo d.. The Green KNob is a cool idea and this is cool to !
http://www.autosportcatalog.com/index.cfm?fa=p&pid=52

Wow! What a selection to choose from. I normally park my 8 in a carport with the car cover over it. The solar trickle-charger would not work for me. I could use the ac trickle charger, but that would only work when I am home...not if I have to leave it at an airport or such. The "green knob" would be a good solution, with the 9v battery memory maintainer plugged in to keep all the settings. My question is: doesn't the cigarette lighter in the 8 turn off with the ignition? If so, would the 9v battery device still work with the ignition off? Has anyone used the autosport Memory Maintainer in their RX-8??

Seeing as how the parisitic drain will pull down a full-sized car battery, I'm not sure how a 9v dry cell could hold out for a month...?

yep, that would be an issue.. but really we need to get mazda to fix this..
You need to remove your trunk light and make sure its not in the Trunk lighting or release mech. On my car it is the ECU .. and nothing elses ..

And yes after 3 days of sitting my Red Top will be dead !
now it sits with my battery maintainer on all the time ..

After considerable web-searching and talking to hardware and auto-supply stores, it seems that most modern vehicles do drain the battery to maintain settings in all the onboard electronics. This is not a "problem" in the sense that anything is wrong, just a short-coming in the design of our modern, gee-whiz automotive gadgetry. The solution I have opted for is a Shumacher automatic charger. The Shumacher manual trickle-charger I initially ordered turned out to require momnitoring, something I cannot do when I am out of town for extended periods. The model I will use is Schumacher SE-1562A. It shuts itself off when the battery is fully charged and kicks in again when the battery starts to get low. I really don't like the idea of having to reset the clock and radio buttons every time I come home, which the disconnect switch will require. Thanks for all the suggestions.

Does the "Green knob" fit in the 8's battery compartment? Kind of a pain to get into that box every time I leave town. Hrm.

Don't know about the Green Knob fitting. Huhsler says (above) that he uses it - I assume in an RX-8. But you would have to reset the radio stations and the other electronic monitoring devices may have to be reset - tire pressure sensor, ABS, stability control, ???

I've had the same problem w/ mine on a regular basis until I put the trickle charger on it (it doesn't get out as much as it used to in sunny TX). One thing the dealer told me to do was to pull the "room" fuse on the car. You'll lose your radio stations though (why I put a trickle charger on it)...

My RX-8 sat for 7 weeks outside, yet it started right up without incident.

I use the green knob disconnect on my older cars, which works well for what they were designed for. Also own a solar trickle charger, as the New Bettle I use to have would drain the battery after 1 week of non-use.

But my RX-8 did great all by itself during November & December.

Mine sat for about 3 days and died. It turns out that the trunk light was on. That is not an exciting design. I charged it up and it was dead in a week but the trunk light wasn’t on. I charged it up again and it sat 2 weeks and started fine. Go figure. I figured that I killed it when it was dead at 0 degrees. I’m going to try to get a new one from Mazda.

I design aftermarket products for cars and I have never heard of parasitic loads draining batteries in a matter of weeks. I always shoot for more like 6 months to a year. Microprocessors are drawing less & less power so things should be better than they were 10 years ago.

I've had problems that sound real similar. I let the car sit for about a week and a half in the cold, under a cover. Went to go start it and all I could hear was clicking, so I knew it was a battery issue. So I jumped it, then drove it for maybe 45 minutes or an hour, then put her to bed. Went to go start it the next day, it started up fine, but I got a check engine light to come on and I couldn't go higher than 2000 RPM in first gear, no matter how much I pushed on the gas. I managed to get back to my driveway and then calmed down a bit before calling the roadside assistance. The guy got there and we tried the car again and it worked fine. The check engine light was still on but I could at least drive it.

Later on, I was told the same thing that you have all been saying here, that the car's electronics take energy from the battery even when the car is at rest, which I wasn't aware of. Another interesting thing I learned is that when jumping the car, you want to have a few or all of your electronics in the car turned ON. This seemed counter-intuitive to me, but I was told that it keeps the car from seeing a spike in voltage when you jump it. I'm pretty sure that's what happened to me, I sent a spike into the system and an engine sensor alarm got fouled up and that was causing my engine run problems. So, turn stuff on when you jump.

Also, if your battery does die and you let it idle for 15 minutes or so (like I used to do with my older cars) to have the alternater charge it back up, you have to be careful. I'm pretty sure the stock alternator puts out 14.5 amps, and I know my tail lights alone use 6 amps and I'm sure the xenon headlights and other gadgets use quite a bit too. So, that's another thing to consider.

For those of you that read this and already knew all of it, sorry to waste your time. I learned a bit here and wanted to share it.

Oops, that was for me!

I was not able to install the Green Knob per the instructions, due to the engine cover and other things around the battery. I ended up using hot glue to mount it on the front of the battery itself, via a velcro plate. It BARELY fits and YES pulling the knob does require that I remove both covers (the other one sort of pins the knob in...if you can picture it...), take it off, then put them back on. Ironically, I've only had to use it once since I changed jobs. Ah well.

Also, if your battery does die and you let it idle for 15 minutes or so (like I used to do with my older cars) to have the alternater charge it back up, you have to be careful. I'm pretty sure the stock alternator puts out 14.5 amps, and I know my tail lights alone use 6 amps and I'm sure the xenon headlights and other gadgets use quite a bit too. So, that's another thing to consider.



If it only puts out 14.5A at idle and the headlights and tail lights were on then the battery would die even with the car running at idle so it must be more than that. Most modern alternators put out close to 100A (lower at idle) but they probably did skimp a little to keep the weight down in this car.

As far as turning all your electronics on when you jump start. I'd say that is bad information too. All the current to start the car needs to come through the jumper cables. If you turn everything else on you will be adding current which creates a voltage drop over the cables. Your dead battery is also creating a voltage drop and then when the starter kicks in there is another. If you are jumping it from another car it's voltage regulator is going to hold the voltage constant so I don't know where the spike would come from. You may have been misinformed.

The solution I have opted for is a Shumacher automatic charger. My local auto parts store stocks Schumacher chargers.

Dumb questions ...
1. do I need a six or 12 volt charger?

2. Is the eights battery a:
A. conventional or low maintenance battery
or
B. maintenance free or deep cycle battery

Thanks in advance,
Oranje

Oranje: The RX-8 battery is 12v, so you need a 12v charger. I believe the automatic one I have ordered is both 6v and 12v.

As to the maintenance issue, the 6 caps do not pop off easily (you have to screw them out) so I don't think that it is "conventional", but since it does not appear to be sealed, I also do not think that it is "maintenance free". I very much doubt Mazda put a deep-cycle in, so I'm guessing that it is "low maintenance". I am supposed to receive my charger by the end of the week (around 1/12/05) & I will add a note as to how it appears to function.

Thanks for the follow-up BB.

Oranje

when i left for london for 2 months last year, disconnected the +ve terminal, came back, hook it up (with 10mm spanner), the 8 started straight away, but read the manual, you will have to turn the wheel full lock left and right after that..... (cant remember what it said exactly :p ).
the 8 has been in the workshop for over 4 weeks, did the same, and started it up yesterday, no prob ;)

Happened to me once, when I went on deployment for 3 months. The next time I didn't arm the alarm, and it started right up when I got back.

Yes, to answer your Q, my battary did die and yes, I had to have her towed in for repair. Bad cell according to the dealer. I also noticed this is a current TSB on the 8. I agree with the responses already, get a trickle charger. The 8 is my second car, I start her on a regular basis to ensure the battery stays good.

- Irish :cool:

I also noticed this is a current TSB on the 8.

Hey Irish,

Can you point me to that TSB? Mine died after a week in really cold weather and probably froze. I want to ge another battery out of Mazda and having the TSB in hand would help.

Thanks.

I have a question. I just got my car out of the shop and it's running great. The did some clutch work and say they replaced my battery becuase it failed the test. I was just wondering if there was a way to tell if I got the 'NEW' battery or just a replacement for the oem.

Can I connect the slow charger directly to battery terminal without disconnect the battery from the car?

Can I connect the slow charger directly to battery terminal without disconnect the battery from the car?

What do the charger instructions say?

I talked with my service advisor yesterday and he wasn't suprised by my claim iof the weak battery and the parasitic drainage of the battery. He told me to be happy I didn't have a lincoln LS. He said those are about 2-3 times as bad as our car. He said cars with navigation systems fair worse than those without.

What do the charger instructions say?

Borrowed from friend, there is no instructions. It has a ampmeter, circuit and overload protection. If I connect directly to battery without pull the battery out, will it damage any electronics?

My car been sitting in garage since Dec. Alarm lights still flashing, but I want it full charge before I start it up.

If it is a slow charger like a wall transformer with a few wires the battery will smooth out any current spikes so don't worry about it. I have charged mine with a full size charger too. You need to worry when your battery is fully discharged and you jump start it using the boost feature on some chargers because the internal resistance of the battery is high so it can't take all the current that is being supplied and the voltage goes up. This would also be when you wanted to turn on all the lights and fans as mentioned earlier in this post.

Bottom line, if you are slow charging just hook up the red and the black to the car and let her rip.

If it is a slow charger like a wall transformer ...
Bottom line, if you are slow charging just hook up the red and the black to the car and let her rip.


Yes, it is slow charger. Thanks.

yep, that would be an issue.. but really we need to get mazda to fix this..
You need to remove your trunk light and make sure its not in the Trunk lighting or release mech. On my car it is the ECU .. and nothing elses ..

And yes after 3 days of sitting my Red Top will be dead !
now it sits with my battery maintainer on all the time ..I am so freakin glad i found this thread.

My car will die if it is not driven once every three days. In the near future i wont be driving it very often at all. I am looking into a battery maintainer and had a few quick questions.

1 - Can you leave it connected to your car all the time or only when the car is not running?
2 - Other than the solar ones, every battery maintainer i have found comes with a cord to connect to the wall. Is this just to charge the maintainer or does it always need to be plugged in to work? I read the instructions on the maintainers and did not mention this.
3 - which ones are you using?

Thanks for the help, much appreciated...
-hS

First of all, if your battery is dying in 3 days you have a problem with unusually high power drain when the car is shut down. The battery charge should last for weeks with a normal dark power drain. You should find the source of the unusual power drain to solve the problem. A maintenance charger is treating the symptoms--not the cause--of the problem.

One problem some owner have had is the trunk light staying on when the trunk is closed. Open the pass-through between the rear seats to see if your trunk light is remaining on with the trunk closed. That's the simplest thing to check. If you have Nav, it may not be shutting down completely when the car is shut down. If those are not the problem, you or a dealer will need to do more-through troubleshooting tests.

But to answer your questions:

1-Since the maintenance charger requires "house power" to do it's thing, it is unlikely you will leave it connected when you run the car. Anyway, your alternator will charge the battery when the car is running.
2-Like I said, most of the chargers require connection to AC power. You remove it when you run the car.
3-Schumacher makes several maintenance chargers. Do a Google search and check out their web site. I occasionally use the Schumacher model SEM-1562A when the car potentially will be sitting for a week or more. This model is a 1.5 amp trickle charger with a quick disconnect capability. Also, Sears sells some of the Schumacher chargers under the Sears brand name.

BigOLundh: I have to leave my 8 parked for weeks, and sometimes months, at a time. First time it was parked for 6-8 weeks it was totally dead. I bought a Schumacher trickle charger on-line from Ace Hardware. When it arrived at my local store, I learned that it could not be left connected indefinitely; you had to monitor it and unplug it when the car battery was fully charged or it would damage the battery. I exchanged it and bought a Schumacher AUTOMATIC TRICKLE CHARGER. I permanently connected the charge-cord to the battery terminals (as the instructions indicate) and then I just plug the charger into the inline socket when I have to leave the car for more than a couple of weeks. It is self-monitoring and has not damaged the battery. I have left it for as long as 5-6 months with no adverse effects and the battery is fully charged when I return and unplug the charger. I've been using it for a couple of years now. Just be sure you get an AUTOMATIC charger.

Now, if your battery is going dead in under 4-6 weeks, you have another problem. The parasitic drain is supposed to take up to two months to run the battery down.

BoomerBurt

One of my mods is causing the drain.. and im just going to have to deal with it.

This automatic charger sounds great, but in the near future my car is going to be parked away from any outlet socket, i dont know how effective it can be when not plugged in. I can plug it in occasionally, but i was hoping for something that could work while remaining unplugged.
For example, when having the car transported... i need to ensure the battery doesnt die, and it will definetely not be able to be "plugged in" at that time.

-hS

What do people think of portable jump-starting systems, such as the Vector Start-It?

The unit can be charged and left in the trunk. One of the Vector models comes with a built-in air compressor that can be used to inflate tires. The unit has an emergency LED light and can also be used as a 12V DC power supply. It can be recharged from a standard 120V AC power source or a 12V DC accessory/cigarette lighter port.

I hate jump staring any new vehicle due to the surge to the electrical system and the ECU

This is interesting. I had just assumed that using a second battery was effectively the same as having a fresh battery: the key is in the "off" position, then when you turn it to 'start" it draws on an (alternative) 12V source of power as it would if the original battery had juice. So there'd be no difference in surge to the electrical system.

I'd be interested in hearing more about this.

Thanks for the great advice guys - I go out of town weekly and have the same problem so this is just what I needed!

had a dead battery saturday. on thursday i had installed the short shifter. i had turned on the map lights while doing th einstall. forgot to turn them off. i didnt notice them on ion friday when i went out fo some errands- too bright i guess or too busy learning the new shifter. any way- hooked it up with cables from the wife's outback one on the terminal and one on th ebolt on the alternator. started right up and no issues since. had to reset the DSC of course

Third week that my car wouldn't start. First week I put it on the trickle charger, got it going. Last week I took the battery in and had it checked. Today I went out and it was dead again.. :( Then, after reading a bit here, I went and check the trunk lid. It wasn't latched.

I think it is a big issue. I am sure my trunk light was on and ran the battery down(Now that's parasitic drain:) ) Well, I hope that's what the problem was, I am pretty sure so.

But, it's easy to hit the trunk button on my key tag. I'll be more careful. Fortunately I read here about a similar problem.

Steve

Just remove the bulb from the trunk light. Not worth much anyway.

Yep, plan to disconnect it. :)

1. 12 VDC
2.
A low maintenance B. maintenance free

I have those settings on my charger as well.

I too once didn't secure the trunk as fully as I had thought. Darn trunk light!

My local auto parts store stocks Schumacher chargers.

Dumb questions ...
1. do I need a six or 12 volt charger?

2. Is the eights battery a:
A. conventional or low maintenance battery
or
B. maintenance free or deep cycle battery

Thanks in advance,
Oranje