We bought a new 2020 CX-5 in early June. We've had it 72 days, and have added 996 miles on it. It gets driven almost daily, usually as far as the grocery store or other short trips, all less than 8-10 miles RT. Today my wife went to start it. The push button was red and the electronic dials were spinning. Dealer service rep told me that is indicative of a low battery voltage. Called for road side assistance. He measured 6 V. Yeah that is way low. He jumped it and then performed a load test. The battery failed the load test. I took it to the dealer (12 mile drive, lights off). They checked the battery and found it to pass. They started the engine ten times in succession. It started every time. They did not replace the battery. I asked about a sneak short or something left on drawing a trickle current and the dealer said no. The headlights are set to Auto, which stay illuminated for about a minute after shut off, if I recall correctly, along with the interior lights.

Could this be a problem of a lot of short trips not charging the battery? The longest drive it has taken is about 20 miles. I have heard rumors that modern alternators are not as robust as they used to be (weight saving), so expect longer to charge. My wife is pissed off, claiming this car must be "special" and that none of other cars ever had problems like this. But then again, she is easily pissed off. Any other suggestions, other than longer drives?

 

The information about the generator is incorrect. If anything would be the total opposite!
I find it interesting that the road service tested your battery as at fault and the dealer test battery ok. I would get it checked again maybe take it to O'Reilly Auto Parts and they will check it for free. . But make sure the battery is fulling charged before the testing.
I would start with that. The battery showing 6 volt really is more indicative of something being left on. You may need to actually read your new MAZDA owners manual again?
Your short drives are more then enough to keep the battery charged up in that MAZDA!


Can't help you about your wife! My wife says our cars only seem to have issues when I work on them. LOL

 

Anything plugged into the 12v power outlets? I'm coming off a GM that
some 12v outlets were off when the key is off.

My 2¢

 

Maybe your 2 cents is only now worth 1 cent... I think you meant some outlets are direct battery supplied voltage even when the ignition is off. Otherwise you response makes no sence at all... at least advise and suggestive help. LOL

Another thing if the service that jumped his battery and also was able to load test the battery I am more then certain logically they would have looked and maybe if they thought otherwise asked about accessories.
And the last thing you should have read is about what his wife, what he said she said about their other cars said which would have clued you into answering you own suggestive question? Perhaps not ?

 

Do you have a multimeter? What about a battery tender/charger? Both are inexpensive and you need them.

I agree that those short trips 'should' be adequate for charging the battery.

If you have a multimeter start checking the voltage of your battery. Check it right after it's been driven then again after it sits for a few days. If the battery doesn't maintain at least 12.3vdc then there's an issue. Also check the battery voltage right before you start the car and then again right after. With the motor running you should see around 14vdc. If not, there's a problem with the charging system.

 

The charging information is not "exactly" accurate for a MAZDA's ECU controlled charging system.

I suggest first to wait to see if the OP continues to have a problem and then because IMHO he does not really like most know how to track and diagnosis a 12volt electrical problem that he returns to the dealer ship or a shop that specializes and Auto electric's.

 

Their answer to your question should have been 'maybe', instead of 'no'. You might want to show them this TSB (below), which they apparently haven't read yet, and ask if there has been any progress on a resolution to this unidentified problem. (although the TSB does mention power liftgate, so they might have already isolated the problem to that system)

Probably a waste of time to do a parasitic draw test, given that the TSB classifies the issue as being intermittent. Regardless if your vehicle's problem is the one in the TSB or something else, you might want to check the battery voltage every day or so. PITA, but monitoring is about the only thing you can do at this point.

MC-10174692-0001.pdf

 

I have a question for @m5xguy, how far from the parking place of your CX-5 do you typically keep the key fob? I've seen numerous reports, from all makes I might add, where owners might keep their key fob within ten meters (just shy of 33') of the parked vehicle. The common consensus/working theory is the vehicle senses the relative nearness of the fob and keeps certain electronic systems up and running in preparation for another trip for the vehicle, thus increasing battery drain. In one case, one of my co-workers had some guests over to his house, one of the guests had a new Nissan which was parked only a few feet from where they sat out in their back yard; after four hours the Nissan failed to start due to a drained battery.

Disclaimer, I've never researched this issue, and never experienced it as our Mazda3, which also uses proximity detection, is virtually always parked an easy 12 to 15 meters from where the keys are kept; said another way, everything I wrote above is a regurgitation of what I've read and heard from other folks, so take my comments with a grain of salt.

 

as well I do .... hahaha!
MX5guy You looked up a TSB but why didn't you do the follow up information about it?


The TSB has no follow up information from MAZDA and MAZDA is not suggesting in any of the Dealer Service updates a problem at least from my info using my shops service data information. I think grim_reaper can verify this information because he works at a MAZDA Dealership and I rely on a paid subscription Service Help Advisory (like AllData only more dealer related which usually includes the most updated TSB information) for the shop I run as Service Manager from time to time whenever I need some extra hobby money because technically speaking I am suppose to be retired?LOL !


Next...
shippo interesting the second half of your responses has interest thoughts for sure. When we go away on vacation for a few days I will typically rent a car rather then beat my cars on a long drive trip. What I notice is the stabilized voltage when I set the car up is my normal 12.03(+/- .02). When we return say about 4 days later the voltage before I start the engine is 11.90(+/- .05). I have a rather interesting alarm and security system so this is not usual to see the voltage readings when the security system is activated. Now when I am home I seldom set the security system or even lock the doors when the MAZDA is parked in the garage. Now what caused me to go WTF... is if I use one of my other cars for a couple day or so the MAZDA's voltage will drop below 11.80? At first I thought because of my stereo system no matter how well I take care of the charging system and battery they only last about 18 months I was going to be replacing under warranty another OPTIMA RED Battery. But.... the battery load test fine and charging system ECU load output was fine! Then I read grim_reaper response on another thread that if you don't manually lock or have auto lock set when leaving the MAZDA sit for any length of time the ECU will not shut completely down? I could not go into the ECU as I do my other cars because their is no one that offers a complete ECU access program (not even OV) to be able to see if this was what was happening . So I did the simple GOLLY JEEPERS DIY way to teat the theory out. I check the resting voltage and then manually on the key FOB set the door locks (but not the security system). 3 days later the battery voltage .02 less then the starting test voltage check? So I now know that if I am not going to drive the MAZDA for a few days to manually set the door locks? Mind you this is by no means the best and Technically Sound way to do a test but it was easy and the results at least in part supported the response that grim_reaper reported!

 

I believe the 6V comment by my road side ***'t guy was flatly wrong, or else I heard him wrong. The battery would have to have 3 shorted cells to drop that low. He did not disclose what "failed load test meant".

Here's some data. I measured battery terminal voltage as follows, starting last evening after a 30 minute drive lights off. I have a digital multimeter, not an analog unit.
Running at 7 pm 13.10 v
Off at 7 pm 12.58 v
Off 10 pm 12.54 v
Off 6 am 12.47 v
Off 10 am 12.45 v
At 10 am I held meter leads on terminals while wife started, and very briefly voltage flashed 9.39 v, then within approximately 1 sec recovered to 13.50 v.
Running 1 min later 13.42 v
Running with headlights on 2 min later 13.40 v

I have a friend with the identical car, down to the trim package. He measured the following
Running 13.48 v
Off 12.52 v

My conclusion is car electrical system is fine. I believe my wife inadvertently left the car in accessory mode after shutting it off the day prior to the problem. Dealer service confirmed that is possible. My '19 taco can go into accessory mode if I am spastic on the button when shutting off, although it beeps quietly. Perhaps Mazda doesn't beep, or she missed it.