[JohnG]

I get it semi regularly. I'd been driving the car a bunch so the battery should have been fully charged. I had doors open while cleaning the interior, no radio on, and got the alarm after a while. I complained about this on the survey they sent out and have read of others having the same problem. I don't think you have anything to worry about as far as having an issue with your particular car, but I'd still call the dealer as more people bringing it up will hopefully lead to a fix.

Driving the car charges the battery very slowly. If you routinely have it in accessory running the radio you will pull the battery to a low state of charge and then it will be even more likely to give you this alert.

FWIW. When a battery is discharged to the point that a car needs to be jump started it takes 8 to 12 hours to bring it back to a full state of charge on a shop's battery charger. It would take at least that much driving time to do the same.

 

[JohnG]

A Hello from Canada,

I really wish the manufacturer would take those things seriously. It should be possible to leave the vehicle doors open indefinitely without discharging the battery completely. If this is actually the case, the engineers that allow such design flaws should rethink how vehicle technology should be designed. There is absolutely no excuse for letting people be stranded because of those ill-fated design decisions.

Remember, there are computers in the car that could intervene and protect itself from complete self discharge. It is high time, that fool proof power management be instituted in new cars. It is unacceptable that all those problems experienced by car owners happen in the first place.

Most manufacturers have been designing and implementing battery protection strategies for years. In fact the notification that some are reporting about the battery getting depleted and being told to start their engine is evidence of just such technology. However there are limits to what is going to work and what won't. It takes time to recharge a battery after a starting event or after an extended drain event has occurred. I can play a little later this week and see if the vehicle will power down with a door left open or not. "Usually" we see about a twenty minute window where the system will identify a potential problem and power down.

Apparantly, with tools such as ForScan and Software some of those values can also be extracted or read out via the OBD2 port. But I had no opportunity yet to explore this avenue.

Scotty73

Forscan will not work on anything newer than 2017, yet. Autel supports up to 2019 as of right now. For access to a 2021 the only real solution is a J2534 pass through device and a short term subscription to MDARS or a full subscription for MDS.

 

[JohnG]

Is it possible to deactivate the keyless entry function, so the car only wakes up and enables the start button if you actually press the unlock button on the key?
As it stands, I can’t even sit in the car waiting for more than about 15 minutes if I have the key in my pocket.

If you only have 15 minutes of accessory time, you have a severely discharged battery. If the battery remains in it's discharged state you will see it have a very short lifespan, easily less than a year. So for now it needs to be recharged and this should be done with a smart charger (not the car's alternator) that will keep the battery at float voltage once the bulk of the power has been restored. It takes about two hours on a charger to restore the battery to about 70% state of charge once it has been depleted to the point that the car has trouble starting. The next 30% takes all night to accomplish and that's where everyone get's into trouble. A battery at 70% is still a discharged battery which shortens it's lifespan.

As far as disabling the keyless entry function that would take some real investigation. Even so, if it could be done it's likely it would include other undesirable side effects. Disabling the oscillators that detect the key would disrupt the push button start too. This is Toyota's system (a version of it anyway) and with knowing how they work I would expect you would need to hold the fob near the start button to start the car using a back-up strategy.

 

[JohnG]

Thank you Hawke---although if we think about it--accumulated events leads to battery failure to start the car. That is what we are trying to avoid here. I am still seeing these warnings in my car after I wash my vehicle and I really do not like them. This time I did not have my key with me--hoping that will help. Obviously, it didn't. There is still something there that is draining our car battery while we are doing our regular washing the vehicle process.

"-although if we think about it--accumulated events leads to battery failure to start the car" This is correct, but only part of what the engineers are trying to prevent with "smart charging systems". One thing often overlooked is that when a battery ends up staying low state of charge, it's total lifespan can be significantly shortened.

I have been watching the battery in my CX for several weeks to gain some insight into Mazda's system and it's not that different from a number of manufacturers. They don't keep the battery at 100% state of charge, in fact it appears that 80-90% is the target based on this chart.

That actually makes a lot of sense because the battery isn't just for starting the car. It helps prevent voltage spikes (it's technically speaking the largest capacitor in the car) in the vehicles systems when it can readily accept any charging current, and it also supports system power under conditions where vehicle demand is higher than the alternator can produce.

Without writing a whole class on smart charging systems here, a test that can be run by any owners willing to do so would be to park the car with the hood open after having just been driven. Measure the battery voltage. This voltage "should be" relatively high (over 12.8v in most cases). This would be considered "surface charge". Remeasure the voltage after the car has sat for an hour. Some decrease in the battery voltage is expected because of both the surface charge dissipating and some normal parasitic loads as modules went to sleep. Repeat this measurement at two hours, three hours, and four hours without disturbing the car and waking modules up. By now everything should be stable and the batteries true state of charge should be reflected by the chart above. If your battery checks out lower than 12.28v, a 60% state of charge then you will be seeing the battery saver message earlier which means the system will not let you keep the doors open, or run the radio (accessory mode) as owners have been describing. That's enough for now, lets see what the battery state of charge is for the owners having issues.

 

[JohnG]

Well John---After I found this post here about a german car maker having this exact same problem since 2004--I am guessing the start of adding so many different sensors to their cars...and now my CX-30 having somehow similar issues.

Right at the beginning of the article it says "Lieff Cabraser is investigating complaints about sudden vehicle battery failures across the Mercedes-Benz line". The majority of the events likely only appeared to be sudden. The perspective that it started "fine" just an hour ago and now it's "dead" is not surprising but the reality is a badly discharged battery (nearly dead) can still start an engine and appear to be fine when it is already in bad condition. So as long as it was starting the owner didn't suspect anything and that's why it is perceived as "sudden". The real question from there is "why" was the battery's state of charge and condition depleted?

One of these days I'll explain the load shedding, and the various stages. Sooner or later someone will notice one or more of them and post some very specific symptoms while the vehicle is being operated. It's probably been happening already with the ones that failed to start and had to be jumped or towed but the manufacturers do try to make some of this less objectionable to owners so they can slip by unnoticed.

 

[JohnG]

This is a snapshot of what is going on. I understand that it's more important to most owners to not have to deal with this at all but a little insight won't hurt IMO. The first attachment is a battery test that I did on my CX April 13th (I had to correct the date if the first test on the printout). The second one I just did today, May 5th.

If you recall the battery voltage to state of charge chart that I uploaded, a battery at 12.54v has an 87% SOC (state of charge). A battery at 12.23v like mine is now has dropped it's SOC to 54%. I don't do much traveling right now and won't until we start getting classes scheduled. The car only went for two trips this past week (total 100 miles), otherwise it's just had several short start-up/shut down events which would pull the battery down. What has to be figured out is how much of the battery's current state of charge is because of how I used the car and how much of it represents a potential issue. Either way the point is, if the battery continues to be depleted I'll soon get the same problems as has been described by others, but it didn't happen all at once. It took nearly a month to pull the SOC down some 30%. It would take about seven weeks from now to possibly encounter trouble starting the car if the trend continues. In the mean time I'll plan to test and prove if it is how the car has been used or if there is something wrong. If there is something pulling the battery down, I should be able to prove what exactly is doing it.

 

[JohnG]

4) I honestly think this is NOT acceptable. To me--I said it before-to my Dealer salesperson and the managers. I never had a car that I had to start the engine "just 5 minutes" so that I had to re-charge the car battery", if I need to finish cleaning my car. That is ridiculous.

If they were claiming you were actually recharging the battery, that would be ridiculous. That's not what the bulletin says however. It states that running the engine for five minutes or removing the fuse resets the timer that the BCM uses in order to judge the battery. It makes sense that this can be a problem in the dealership showroom with all of the times that the doors, liftgate would be opened/closed and the car not actually started say over a week or more.

5) The fact that some people had killed the battery while washing their cars—I am guessing, because I do not have the specific details, that they failed to see or hear this warning and or ignored it and did not start their engine. That lead us to the next question—I think John can help us here.

6) If we are cleaning/washing our car—and then this warning shows up and we do not start the engine—how long it will take to kill the battery?

The battery has a reserve capacity of approximately 50 amp/hours. That of course means you can pull fifty amps from the battery for one hour (If it was at a full state of charge and 100% state of health when you started) and there "should" still be enough energy left to start the engine. That also means 25 amps for two hours, 12.5 amps for four. and at the six amps that I showed flows when the car wakes up from touching the door handle, about eight hours total.

 

[JohnG]

Wow--that is a lot of juice.

Then--we are still in the dark as to what is actually killing some people car batteries--sometimes.

Yes we are.

Like is the case of Marisela's car (from FB CX-30 owners) --when she remembers just one day--she left the windows down a little and then, next day car was dead. She immediately connected that action with killing the car's battery

Which leads me to one of my favorite little anecdotes. "I never noticed it before________" Where does that say that whatever the subject being referred to is in fact new? In most cases the person making the statement didn't have a reason to look or pay any attention to the subject. But then given a reason to and in a technicians case having done some repair now the owner actively looks for any other problems and the rest is easy to figure out.

---and then, when reading about the Intrusion Sensor--that in it, it recommends we close the windows fully because maybe, this sensor could get activated with just wind, isn't that weird? So, in her case---was that sensor activated or get awaken to a point in which it kills her car battery?

Read the rest about the intrusion sensor and what it does if it detects movement and see if that supports "M"s car.
(This is the online Mazda 3 manual with the same system. ) Mazda3 Owner's Manual Scroll down for the link on the intrusion sensor page

 

[JohnG]

Summary Request : Is there an actual fix for the Low Battery Risk warning?

Thanks for everyone's time in trying to help all the owner's with this problem, but after reading several hundred posts I still have not come up with what the fix was? I've literally owned my 2021 CX-30 Turbo AWD for 3-DAYS and already have this battery warning issue.

There is no "fix" because it's not broken.

Several posts stated "I no longer have this problem..." What was the fix, or what do you suspect you did that stopped this annoyance? NavyDale

The most likely thing that anyone has done is simply use the car more and/or not leave it sit with the ignition on. Just about every vehicle you can buy today has advanced power supply strategies that can result in these kinds of warnings depending on the batteries state of health and state of charge.

 

[JohnG]

When you charged the battery, did you connect directly to the battery? Or, did you have the negative cable connected to the engine or the jump start terminal?

 

[JohnG]

One day one I had the negative clip attached to the jump start terminal (as per owner's manual section 7). On day two, I connected the Battery Tender directly to the negative terminal of the battery.

The reason that I asked is there is a battery current sensor that is always measuring how much current is entering or leaving the battery. This helps the body computer calculate the batteries SOC (state of charge) and it's SOH (state of health). When the charger is connected directly to the battery the body computer cannot measure how much power is flowing into the battery so it forces the system to have to do an engine off test that takes get four to six hours to complete. The main thing right now is it sounds like the battery should be getting close to full charge and that should make it less likely to cause the warning.

 

[JohnG]

And that make sense according to the service alert statement. Because it isn’t looking at the battery- no amount of charging will clear it. Needs 5 minutes running.

Chrysler's system also gives us another piece of data to deal with, SOF ( state of function). That is the lowest voltage seen by the engine control module when the starter first engages. In the first .003-.005 seconds of engagement the current flow is usually 600-800 amps and that pulls the battery voltage down relative to the battery's true health. Even though we don't see that data pid with the Mazda system, they are very likely to also be capturing that information on start-up.

 

[JohnG]

I don't now the specific parameters Mazda checks, but I assumed they are monitoring stuff like this. Aside from the alert being annoying, it is disappointing that they base it on door openings when it could be looking at actual battery strength. As I mentioned previously, I measured 12.4v 'resting' voltage on mine. While that is plenty to start it, I'd expect that to be closer to 12.6 on a new battery. I will check it again soon. Maybe I'll run a charger on it and see if it holds a higher level. I measured the same 12.4v after tripping the alert by opening doors.

They don't want the battery at 100% state of charge. At that level it cannot absorb voltage spikes easily. 12.4-12.5 would be the normal range to keep the battery at. There is so much more to power management systems than just about everyone realizes. The updated training classes for professional technicians who are already very knowledgeable about vehicle charging systems is 24 hours in length. That BTW is just the 12v systems, non start/stop. By the time we start talking start/ stop and add in 48v and hybrids it's a staggering amount of information to have to study.

 

[JohnG]

Either way Mr. Kiyotaka Shobuda should be ashamed that it takes his software engineers over a year to change a simple timer parameter from 30 minutes to 90 minutes, in particular, when it was their own idiotic idea to make it 30 minutes to start with. Any kid given the original source code can do it in a couple of hours including debugging and testing.

"IF" rewriting the timer is so easy, can you just go ahead do it for everyone? Just make sure you consider how the change might impact the battery's SOH (state if health) and SOC (state of charge) for the start/stop system to function properly. Plus be sure that the system can maintain the battery at a sufficient state of charge to allow it to support the alternator at low engine speeds, and also not aggressively have to get recharged to the point that it risks shortening the battery's expected lifespan. Plus don't forget the battery's job of dampening system voltage spikes. That's another reason to closely regulate the state of charge/discharge that the battery is subjected to and to make sure that the battery lasts for its predicted lifespan. There of course is still way more to it than just being able to start the engine but surely anyone that can write code knows all about that too, right?

 

[JohnG]

I know that if I had seen the alarm when I was reviewing the vehicle prior to purchase I would not have bought it and gone with another choice.

Cheers, .. Dino

Off hand I cannot think of any manufacturer that does not have a similar system. Smart charging systems, including discharge warning messages and even load shedding (automatically turning things down or off) in order to ensure the battery's SOC and SOH are an absolute must with the sensitive electronics onboard today's cars.

 

[JohnG]

Unfortunately, low battery risk warning has nothing to do with the SOC or SOH of a 12V battery. On my car I can generate this warning, when the car is connected to CTEK MXS 10 charger being in Step 7 (Float) and Foxwell analyser indicating SOC 100% and SOH 100%, by simply opening/closing doors 6 times with 5 minutes interval. I can get the same warning even when the car is running from mains in MXS 10 "Supply" mode (13.6V/10A) with 12V battery disconnected. This warning is simply generated by a timer counting 30 minutes of accumulated onboard electronics awake time between 2 successive engine runs irrespective of SOC or SOH. Everything you said about the relation of SOC and SOH to the battery state and electric power demands is correct. I don't know about US, but in the UK CX-30 is a MHEV and, therefore, doesn't have an alternator as such, it has an ISG (integrated starter/generator) and a DC-DC converter instead. iStop system is purely run by the hybrid 24V battery rather than a 12V battery and, therefore, has no relation to the SOC or SOH of a 12V battery. The same applies to all other functions you mentioned as, when the engine is running, it is a 24V hybrid battery that does all the work including charging 12V battery through a DC-DC converter. I would have loved if Mazda did what you are referring to and had a true indication of 12V battery SOC and SOH rather than a meaningless low battery risk warning based on a primitive timer. I don't want to start an argument here but I can't see how a timer is related to SOC or SOH for this matter, in particular, when the timer generates a warning for a disconnected battery, as mentioned above.

I don't want to start any arguments either. BTW. It's a good practice when using acronyms to write out what they stand for at least once. MHEV is a "Mild Hybrid Electric Vehicle" which is a category that any vehicle today that is equipped with start stop technology falls under (along with a number of more advanced systems). In the training classes that I present for professional technicians we cover four basic systems from vehicles that use more than one 12v battery, to the DC/DC convertor systems, to the capacitive system (Cadillac) and even the 48v versions. That being said, the engineers don't want the battery to be at 100% SOC (preferred is between 80~95%). When a battery is at 100% SOC, it cannot accept any more power which means it cannot absorb voltage spikes when they occur. (Think of the battery as the biggest capacitor in the car) By keeping the SOC in the "sweet spot" the battery dampens voltage spikes, produces plenty of power when needed to and has the greatest life expectancy.

SOH and SOF (State of Function) vary depending on the platform. SOH is a value that slowly degrades over time unless excessive charging or discharging occur, then that can be significantly accelerated. (Think of SOH as the gas in the tank. You can have a ten gallon tank but if it only has five gallons in it it can only provide five gallons worth of energy.) SOF is a value that represents the battery's maximum capability.

When I see the TSB reference it makes me think of this piece of advice. One of the biggest mistakes anyone can ever make as a technician is to try to fix something that isn't broken. Since it isn't broken the technician WILL FAIL to fix it. The problem from there is by trying to fix it, the technician will succeed in proving to someone else that what ever the concern is it must be in fact broken and he/she cannot fix it.

 

[JohnG]

I had exactly the same problem yesterday and couldn’t get out of the car until it was sufficiently charged. Really disconcerting. Did you find any answers from the dealer?

What do you mean by "you couldn't get out"?

 

[JohnG]

Keep the fob in a faraday bag as i do and the alert rarely goes off....imhave a secure , locked garage so i keep the fob in the cal all the time in the faraday bag and i have no issues

I did a parasitic drain test which includes proving if the vehicle will react to the key fob. You can watch it at the link. Parasitic Drain Test - YouTube

 

[JohnG]

Having gotten to see how much of the systems in today's cars overlap I thought that I would share some insight here. The short answer to just tweaking the software and changing the timer because a percentage of owners don't like something about it isn't as easy as one might think. Software corrections when proposed have to be tested to prove that they don't negatively impact the FTP ( federal testing procedure) Emissions levels that the car was certified for when it was first produced. On the surface it might not seem like a big deal just letting the battery experience some longer drain events. But the federal emissions testing is going to want answers to things like how will this impact fuel economy? When the battery is allowed to drain more, the alternator is going to demand more power from the engine for a longer period of time in order to try to replace that consumed power. That additional engine load will lower the fuel economy and lower fuel economy equals more CO2 and pollutants released to the atmosphere. Consider this as an over simplification of just what all can be involved in something like a software change there could be numerous other concerns that could result from something this innocent of a change and rooting them out before just tossing out any random change probably drives some of the engineers crazy.

 

[JohnG]

What would be a "smart charger" for our car battery? Had an issue today with a dead battery.

Good
Amazon.com: Schumacher SC1281 100 Amp 30 Amp 6V/12V Fully Automatic Smart Battery Charger 100A Engine Starter and 30A Boost Maintainer and Auto Desulfator Advanced Diagnostic Testing : Automotive

Better
6/50/225 AMP, 6/12V WHEEL CHARGER MC1300 | Matco Tools

Best.
https://shop.snapon.com/product/Battery-Charger-Plus™/Battery-Charger-Plus™-LiFePO4/EEBC500B