Battery Goes Dead

JMEmden

My 2008 Mazda CX-9 has a starting problem.

If you do not drive the car for a day or two the battery goes dead. If you drive it everyday there is no problem. I have had three repair shops tell me it is a bad battery. So I have purchased 3 new batteries and still the same problem. The last battery was with the dealer. I even had the car towed to the dealer when the battery was dead. They said that was the only way to tell.

But I can tell you that the change of batteries was not the problem. After you jump the battery, the car operates fine. And it will never happen if you drive it every day. Only a problem when the car is not started for 24-48 hours.

Everything in the car works normally. The exception is the Bluetooth voice recognition system. That does not respond at all. But the radio, navigation and other parts of the audio system seems to be working ok.

Can someone help me out?

John Emden

Mr_Shiftright

You'll have to test for a parasitic drain. On some cars this can be a bit tricky, but generally if the testing meter shows a constant draw of more than 50 milliamps, it's probably enough to drain the battery eventually. Naturally the testing has to be done with everything OFF--the tricky part is that some modules don't turn off right away--but they should sooner rather than later. Occasionally, some component other than a module is at fault--like the electronics in an alternator.

Another possibility is that the charging rate is too low. The battery is being charged, but not replenished enough, and sooner rather than later it loses strength and dies.

stranger2020

Hey dude. Have you found out what was the problem ? My car has the same issue, and I don't know what to do. I have Mazda RX8, and I can't crank the engine. It's starting from the 3-4 try, and the problem dissappears once it was started. I thought that it's because of the battery, I have even found an article about how to jump start the car on https://www.otopartshop.com/ultimate-guide-on-how-to-jump-start-a-car, but the problem is not in the battery. I think that it's all related to the fuel pump. What do you think about that?

JMEmden

No changes to date. Goes dead every other day if I skip driving it one day!

I buy a new battery and I will get an additional day out of it for about 6 months.

Have to buy a new battery every year. Frustrating!

No shops can find any problem.

joswald

@JMEmden I’ve been having the exact same problem over the last several months. In fact, AAA contractor was just here to jump my 2008 CX-9. The magic number of days for me seems to be three (3). Over a regular weekend, it starts Mon AM. Over a long weekend, not dead but not enough juice to start the car. Mechanic, a good one, kept it for severals day to try and figure-it-out.

My Bluetooth stopped working a couple years ago. It was drawing some current but not enough to explain the battery drain. Mechanic disconnected it anyway. My CD stopped accepting dics several months ago (not sure how many). But after time with Mechanic, CD changer is working again.

We can’t be the only 2, can we...?

thecardoc3

No you are not the only two, but there is more than one possible cause. Parasitic drain testing takes time and patience. It might only occur for random periods of time which means it can only be pinpointed while it is happening. An electronics specialist would have the tools and skills to work through this.

joswald

Thank you for the post @thecardoc3. Can you give a little more context on what you mean when you say "electronics specialist?"

joswald

I got a tip that the ground connection shown in the pic could have something to do with a parasitic drain. I'm going to post on a few Mazda Forums. Hope to get a few bites...

JMEmden

How do you think the ground in the photo is causing the drain?

My problem has remained the same. I would like to figure it out!

joswald

@JMEmden Not sure about the ground. But, I did find a local specialist - https://www.keystoneautoelectrical.com/. Jerry's going to call me on Mon. I'll let you know what happens. I've been working from home, like millions of others. I had to have the car jumped twice this past week, Tue and Today, because I forgot to start it last weekend and yesterday. What a PITA...

joswald

Hello @JMEmden ...car has been at https://www.keystoneautoelectrical.com/ since 1st thing Wed (25th) morning. Still working to find root cause. Tech is confident the issue is caused by something in the cabin. He can duplicate the draw - no battery connected -> battery connected -> no draw happening -> ignition switched ON -> ignition switched OFF -> draw happening. Not a simple problem. We'll see...

joswald

@JMEmden OK...here's the deal...Jerry at https://www.keystoneautoelectrical.com/ isolated and repaired the problem. The relay for the Rear Defroster was bad. Hard to believe, but that was the problem. The cause of your problem may be different @JMEmden. But, may be worth-a-try to replace the Rear Defroster relay. Good luck...

ClutchRider

For me, the connection to the bluetooth was slowly draining my CX-9 battery. My mechanic solved the problem, but I lost my Mazda bluetooth.

JMEmden

I gave up and traded the car in.

My blue tooth stopped working a few years back. That was likely the issue.

has the car for 12 years. It was a great vehicle. This was one of the very few problems!

Thanks for all your help!

joswald

Unfortunately my CX-9 is gone as well. It was totaled in an accident. Great vehicle - high quality, fun to drive, agile, reliable. Miss it. Replaced it with a 2020 Volkswagen GTI. From zoom zoom to farfegnugen...GOD BLESS AMERICA