Low Voltage Risk-Start Engine alarm
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It seems we have two conflicting threads on this site.
There’s this one talking about false alarms for low batteries, and several others about actual low battery charge levels.
The attached graph shows that the charge does gradually deplete on them whenever they’re left standing, especially when they’re unlocked for cleaning.
When unlocked under certain conditions ie the fob is within a certain distance
and still interacting with the car the systems are activated and voltage will be depleted.
The new update covers having the door open for 30 min or opening a door/hatch 5 or more times and getting the alarm.
and still interacting with the car the systems are activated and voltage will be depleted.
The new update covers having the door open for 30 min or opening a door/hatch 5 or more times and getting the alarm.
This comes down to perception. To a lot of owners the warning that was designed to prevent unnecessary battery depletion is "the problem" versus actually depleting the battery. In time they will discover "a new problem" when the battery fails and has to be replaced or certain vehicle functions are forced into limited operation (load shedding) in order to have more charging system voltage to try and increase the batteries state of charge .
The key was taken away once the car was opened up for him to do the inside, but I still had to go for a drive to make sure it was recharged after he’d finished.
This leads to the technical side of the issue. The time scale with your waveform isn't labeled but it appears to show an engine start and a momentary charging system output that quickly drops back close to the battery voltage of just around 12.1* volts. Most of the alternator's output will be used to operate the vehicle and accessories. Only a fraction of it goes to recharging the battery and even then what the battery is able to accept is limited by the physical characteristics of the battery.
At 12.1v a battery's state of charge is approximately 40%. A group 47 AGM battery has about 105 minutes RC. (Reserve Capacity.) The RC of a battery means a fully charged battery can output 25 amps for (in this case) 105 minutes and still have enough energy to start the car. A battery depleted of it's reserve capacity is fully discharged and is essentially a dead battery but still has just enough energy to start the engine. To replace that reserve capacity it takes slightly more than double the RC time at 25 amps, IF you could actually get the battery to accept 25 amps of current. Unfortunately it only does that for about 1/3rd of that time and then the current it will accept drops as you get closer to full charge. Without dragging this out with more details, it would take about six to eight hours of driving to fully restore the battery when it has been depleted down to 12.1v.
Thank you for posting this. It's a little disconcerting that Mazda admits the alert also means customers "may have problems starting the vehicle". Updating the programming will lengthen the time it takes for the counter to sound the alarm to 90 minutes and it will clear upon startup. However, this doesn't address the battery capacity and overall engineering of that system. My car only has 6700 miles on it and I purchased it in May of last year. From the beginning.... starting it on really cold days was interesting. Very slow cranking to the point I wondered if it was going to make it. This is not confidence inspiring. I've been driving since 1978 and I've owned scores of cars....most of them new. I've never worried about this type of thing with a new car. And, I've never purchased a car this expensive. My 2019 MX-5 GTS was close. Expensive trucks are another story and a sore spot with my wife.
Can our vehicles accommodate a larger, more powerful battery to overcome this?Thank you for posting this. It's a little disconcerting that Mazda admits the alert also means customers "may have problems starting the vehicle". Updating the programming will lengthen the time it takes for the counter to sound the alarm to 90 minutes and it will clear upon startup. However, this doesn't address the battery capacity and overall engineering of that system. My car only has 6700 miles on it and I purchased it in May of last year. From the beginning.... starting it on really cold days was interesting. Very slow cranking to the point I wondered if it was going to make it. This is not confidence inspiring. I've been driving since 1978 and I've owned scores of cars....most of them new. I've never worried about this type of thing with a new car. And, I've never purchased a car this expensive. My 2019 MX-5 GTS was close. Expensive trucks are another story and a sore spot with my wife.
Ok thought we had the issue with the"Low Battery warning" display being solved with the Bulletin
notification posted above post #227
Took my CX-30 in today with the specific purpose of having the update downloaded
after 2 hours I was told the the bulletin has been withdrawn by Mazda due to causing issues with
other computer systems?
What I did get was a new battery, yes the original always sounded weak from day one even with me
charging it periodically.
As to the main reason for my visit the warning alarm, the service manager did not recommend either
pulling the fuse or disconnecting the battery due to possible codes being thrown.
So I'm still unable to leave a door open or have 5 openings per 30 minute period without that dam
alarm sounding.
notification posted above post #227
Took my CX-30 in today with the specific purpose of having the update downloaded
after 2 hours I was told the the bulletin has been withdrawn by Mazda due to causing issues with
other computer systems?
What I did get was a new battery, yes the original always sounded weak from day one even with me
charging it periodically.
As to the main reason for my visit the warning alarm, the service manager did not recommend either
pulling the fuse or disconnecting the battery due to possible codes being thrown.
So I'm still unable to leave a door open or have 5 openings per 30 minute period without that dam
alarm sounding.
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Responding to #229 Steve56. My husband (Mech Eng) recommended this battery based on search. What does this group think? (I know that the dealer has told me that a non-dealer recommended battery "MIGHT" invalidate the warranty). Battery: INTERSTATE Brand (MTX-47/H5), Group Size H5, 650 Cold Cranking Amps (CCA) and 3 year warranty. Interstate Batteries | MTX-47/H5. Approx $200.00
After my battery failed, I have deleted the application that allows auto start and tire pressure monitoring, store my keys over 100 ft away in a metal container, changed all options recommended and those I could find that support communication outside the car, and unload groceries and clean interior while the engine is on. Big PIA and just wondering if the solution is a bigger battery. I've had the car a year and have only 4k miles and routinely don't drive it much. I certainly don't ever drive it 6 to 8 hours at a time like JohnG #226 hypothesized would take to fully recharge. Its going to sit for a few weeks in April without being driven and we'll see how it does.
As to a bigger battery I also asked that question, I was told they looked into it and came up with 1 option
this being in Canada. Theoretically if a battery fits physically and terminal orientation
is doable increased cranking amps should not be an issue.
My previous battery from day 1 felt week on starting even when used with a pulse type battery maintainer
yet this one today seems noticeably stronger ie quicker starter rotation.
this being in Canada. Theoretically if a battery fits physically and terminal orientation
is doable increased cranking amps should not be an issue.
My previous battery from day 1 felt week on starting even when used with a pulse type battery maintainer
yet this one today seems noticeably stronger ie quicker starter rotation.
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After sitting for a few weeks the car started normally. Still interested in the battery issue. Just takes one time (battery failure) to get paranoid about a car not starting . . .
Very informative Scotty. Thank you for taking the time to write this up. As a career electronics technician in the US Navy, I too find it shocking (see what I did there?) to see that modern engineering couldn't come up with a better solution for power management.A Hello from Canada,
I bought recently a CX-30 and run into this reported behaviour. Hence, I decided to investigate the power management of the vehicle by inserting a Current meter between the negative Battery post and Chassis Ground connection and explored the current draw during the various operating states.
1) When the vehicle is locked and at sleep, after a few minutes the battery current drops to 0.007A or 7mA. This is very good as parking the vehicle for a long time (Airport Parking Lot) wonˋt be much of a problem as any lead acid battery has comparable self discharge rates. Three month non-use should be possible.
2) Whenever the keyfob is used to unlock the car the current initially jumps to 11.7A (with headlights on) and then drops to about 4.5A after the headlights turn off after some 30s. Opening the car door adds 0.5A.
3) entering ACC Mode 1 by pressing the Start Button causes the car electronics to wake up with the center display and dash coming alive. In this state it draws continuously about 4.5A. Playing the radio does not change that, although playing it loudly will increase current draw. That explains why the warning is issued after some 20m.
4) entering ACC mode 2 by pressing the Start Button twice causes current drain to increase to 11.7A.
5) when the car is in sleep mode and you press the map light button, the car wakes up and it draws again 4.5A. The map lights themselves draw only 0.2A. (It is not quite clear, why so much car electronics must activate to simply turn on the map lights. But this is how they design cars nowadays).
The following current values are derived by extracting the differences between switch settings as the basic current drain of 4.5A is always present. For example, headlights current is 11.7A - 4.5A = 7.2A.
6) Break lights draw 0.6A
7) headlight draw together 7.2A or 3.6 each.
8) Steering wheel heater draws 4A.
9) when powering the car down, the current stays initially at about 4.5A. After a few minutes it suddenly falls to 0.23A and after another minute or so to return to sleep mode of 7mA.
To put this in perspective with respect to the battery capacity used up by the time you get the first low battery warning, a word might be in order. It is likely, that the fully charged battery is of a 55AH type. Now, with using the radio for 20min you would have consumed 4.5A for 20 minutes or 4.5* 0.33 = 1.5Ah. That means, that in one hour you would use up about 8% of a full battery's capacity. Now, If you were driving a long distance and you get stuck at the ferry terminal waiting for the next ferry, you could safely play your radio for 1-2hours, assuming the battery is in good condition without restarting your engine. Make sure, you are using Accessory Mode 1 which is the first Active state when pressing the Start Button once. If you are not careful and select accidentally ACC Mode 2 you will be drawing almost 12A and draining the battery much faster.
I have not tested yet what happens long term with the doors open. Will the system go back to sleep or continue draining the battery at a 5A rate until it is empty?
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.
What good is a vehicle, that one cannot trust, as far as power states are concerned? When I leave the vehicle I want to be implicitly able to trust, that the electronics is not pulling a fast-one on me.
Anyways, it is my hope, that the above information helps in understanding what happens in the vehicle during the different active states.
Warning: Be careful when performing measurements on your own and avoid at any cost starting the engine. You will likely blow the fuse of the meter or destroy it thoroughly. Even the vehicle could potentially become damaged. I also inserted my meter without breaking the circuit and causing system restart issues.
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.
I am not happy with the findings. As an industrial electronics HW and SW designer I find it appalling that cars are designed this way. the map lights should not require a Stage 1 system power up. An independent microcomputer controller could have handled that by itself without getting the rest of the car involved.
Also, not being able to play the media unit for a very long time while stopped in traffic (construction site delays, ferry waiting times) is dissppointing. In my previous car I had an ALPINE media player and could run it just about forever. Picture waiting for a missed ferry for two hours
It is a sad state of affairs to design vehicles this way. It proves that sensible power management of the vehicle us not a very high design priority. The excessive complexity of modern technology in general is an Achilles heel and can contribute to excessive future expensive repair costs, for which the car owner cannot be made responsible, but still pays outside warranty period. I guess, that is the price we have to pay for having "Digital" everything in our lives nowadays...
The lack of a front 12V outlet us also an irritant to me.
On a personal note, I had to purchase another vehicle because a semitrailer truck destroyed my previous one while parked. I drove a 2006 Toyota Matrix before and the differences between 2021 and 2006 are shocking. The Matrix was the most reliable vehicle I ever owned and had over 230000km on it With only minor repairs. It was practical and sensible. I would have bought a new one without hesitation. The CX-30 is a lovely replacement. But will it be as longterm reliable? The direct injection principle seems to imply periodic valve cleaning actions every so often. Why do the spark plugs only last 1/3 the Toyota ones did? At the time, I very much enjoy the vehicle. It is a pleasure to drive and very comfortable.
Another potential problem is the position of the Center Console USB jack. What idiot placed it in such an exposed position so that, when an USB memory stick is plugged in, it is very easily possible to knock it and damage possibly both the USB device and the USB jack inside? (I recommend buying a right angle USB extension cable, so the the USB memory can be lying on the bottom of the storage compartment connected to the other end of the USB cable and no longer risks being inadvertently being damaged by normal use of the storage compartment).
Not really on topic here, I have also discovered some somewhat annoying software bugs in the entertainment system that should have been caught by Mazda software quality assurance. But it is nearly impossible to motivate the manufacturer to adress such flaws and it is unacceptable that we owners have to live with such probiems because those problems are not important enough to them. It is absolutely appalling how much flawed software is in our lives nowadays In all kinds of technology products. Forget about talking to the dealers. They can't do anything other than load newer firmware. Those problems can only be addressed by the appropriate company Engineering Departments.
Anyways, all the Best to all of you,
Scotty73
Got the update! And As far as I can tell it worked. Had it done yesterday. Today was local ‘yard sale day’. I stopped at numerous sales less than 5 min apart. I’m certain this would have given me an alert with previous programming. But today it didn’t. 👍 the real test will bee when I wash and vacuum…
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Yes I get this warning too. Why? And I have to start my car to charge it. That is crazy. How come this is happening? Toledo Washington.
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