[ColinW]

Hi,
On my Skyactiv X GT Sport I had a flat battery similar to reports on this forum, like some others even after I had fully charged the battery I had faults reported. I left the car for a couple of days, battery was fine, but the vehicle would not start and had to be dragged back to the dealer on the back of a recovery vehicle.

The only explanation I got from the dealer was that the battery was faulty and had been replaced. The manual specifies that the battery should be “12V-60Ah/20HR or 12V-65Ah/20HR”, however the replacement fitted is a “20HR 55Ah CCA 355A” a smaller capacity. Mazda say that this smaller battery has been approved for the CX-30.

I wondered what other peoples experience is and indeed what battery is fitted to your cars? I am interested in the capacity and the CCA (Cold Cranking Amps) specification.

 

[detailcarguy]

Here is the battery in mine that came with it right from the assembly plant.

 

[CleddauMart]

Hi,
On my Skyactiv X GT Sport I had a flat battery similar to reports on this forum, like some others even after I had fully charged the battery I had faults reported. I left the car for a couple of days, battery was fine, but the vehicle would not start and had to be dragged back to the dealer on the back of a recovery vehicle.

The only explanation I got from the dealer was that the battery was faulty and had been replaced. The manual specifies that the battery should be “12V-60Ah/20HR or 12V-65Ah/20HR”, however the replacement fitted is a “20HR 55Ah CCA 355A” a smaller capacity. Mazda say that this smaller battery has been approved for the CX-30.

I wondered what other peoples experience is and indeed what battery is fitted to your cars? I am interested in the capacity and the CCA (Cold Cranking Amps) specification.

Interesting - I have just had exactly the same problem on my CX 30 Skyactiv X GT Sport Auto. Battery died, recharged, car ok for a couple of days, then total software failure of the Body Control Module. Car had to be dragged onto a recovery truck. Sat at dealers for 11 days until I was asked to collect it. Mine was only 10 days old when the battery went flat! I have now been told " not to listen to the radio or have the interior lights on for more than a couple of minutes-not even remain in the car for more than 5 minutes(because of the key fob presence)-unless the engine is running! This was from Mazda UK Tech Support!! I will be rejecting the car tomorrow on legal advice.

 

[steve67]

Interesting - I have just had exactly the same problem on my CX 30 Skyactiv X GT Sport Auto. Battery died, recharged, car ok for a couple of days, then total software failure of the Body Control Module. Car had to be dragged onto a recovery truck. Sat at dealers for 11 days until I was asked to collect it. Mine was only 10 days old when the battery went flat! I have now been told " not to listen to the radio or have the interior lights on for more than a couple of minutes-not even remain in the car for more than 5 minutes(because of the key fob presence)-unless the engine is running! This was from Mazda UK Tech Support!! I will be rejecting the car tomorrow on legal advice.

Rejecting the car can be a long process, hopefully you have a understanding dealer that will advise and help you.
we returned a car a few years ago, due to paint problems, luckly our dealer bought the car to speed thing up, if not i could of taken months to sort out apparently.

 

[ColinW]

Interesting - I have just had exactly the same problem on my CX 30 Skyactiv X GT Sport Auto. Battery died, recharged, car ok for a couple of days, then total software failure of the Body Control Module. Car had to be dragged onto a recovery truck. Sat at dealers for 11 days until I was asked to collect it. Mine was only 10 days old when the battery went flat! I have now been told " not to listen to the radio or have the interior lights on for more than a couple of minutes-not even remain in the car for more than 5 minutes(because of the key fob presence)-unless the engine is running! This was from Mazda UK Tech Support!! I will be rejecting the car tomorrow on legal advice.

Here is a brief account of the problem I had with my car, I thought it might be of interest to you.

1. The day I took delivery I drove it about 40 miles home, parked the car made sure everything was switched off and the car locked. Later that day, in the evening, decided to explore the infotainment System. Switched the vehicle into ACC mode, within 10 or 15 minutes the display dimmed. I thought this might be some sort of timeout so I switched from ACC to ignition ON. The electrical system “died”. Any electrical device that I tried no longer worked. I opened the bonnet and directly measured the battery voltage with a Multimeter, it indicated 7 volts.
2. When I had eventually charged the battery enough to start the vehicle I had the following warnings: : “Check Engine” light, “Keyless Entry System Malfunction”, “Push Button Start Malfunction”. Stopped the engine, disconnected the negative battery terminal and left it for some time. Reconnected the battery, “Check Engine” fault indicator no longer present but other two fault indications were. However both Push Button start and Keyless Entry System appeared to be working. Went for a short drive, then returned home with no further problems presenting.
3. Left the car for a day without touching it at all, when I eventually thought I would give it another chance I was unable to start it; could not even put the System into ACC mode. I measured the battery voltage at more than 12v.
4. Mazda Assistance were not able to start the car either so eventually it got dragged off the drive and returned to the Dealer where it stayed for just over a week.

I would be interested to know what information your Dealer gave you about the cause of the fault. I would also be interested to know if the battery was replaced and irrespective of that what the battery spec is.

 

[Moonan]

Hi, I am new here and have recently bought a CX-30 with the X engine in Australia. 5000km in the first 6 weeks and no problems. My wife has a long commute.....
Just reading this article out of interest, and I am curious. Do all X engined-CX-30s have the M-hybrid system as they do here? If so, I am wondering why there isn't any mention of the 24V battery in all of this discussion as it operates the starter. I know that the 12V battery is the "house" power, and operates all of the systems, but for the car not to start there must be some interaction with the 24V system? For example, the CCA rating of the 12V battery wouldn't be all that important if the 24V battery always does the cranking..
I am writing from a position of supreme ignorance here so please correct me if I am way out with what I think.
.

 

[ColinW]

Hi, I am new here and have recently bought a CX-30 with the X engine in Australia. 5000km in the first 6 weeks and no problems. My wife has a long commute.....
Just reading this article out of interest, and I am curious. Do all X engined-CX-30s have the M-hybrid system as they do here? If so, I am wondering why there isn't any mention of the 24V battery in all of this discussion as it operates the starter. I know that the 12V battery is the "house" power, and operates all of the systems, but for the car not to start there must be some interaction with the 24V system? For example, the CCA rating of the 12V battery wouldn't be all that important if the 24V battery always does the cranking..
I am writing from a position of supreme ignorance here so please correct me if I am way out with what I think.
.

As far as I can see from the specs even the base model X has the mild hybrid system, and indeed mine is certainly M-hybrid.

It is unclear to me what interaction there might be between the hybrid system and engine start up. The hybrid battery is charged parasitically from regenerative braking and as far as I can see not from whatever passes for an alternator, which does however charge the 12 Volt system. I had originally speculated that the hybrid system was only used for engine start when i-stop was in use. I had not considered that it might be used on initial “cold start”.

Looking at one of the UK Mazda websistes
www.mazda.co.uk/why-mazda/mazda-m-hybrid
I found this:
“When you decelerate, the integrated starter motor generator produces electricity which is stored in a 24 volt battery. This electricity is used for a number of purposes including starting the engine and providing motor assistance when you pull away. It can also power the car’s electrical systems.”

I am still unclear of the hybrid interaction. My interest in CCA rating of the battery is to try and get some idea of what my original 60AH battery CCA spec might have been since it in not noted in the manual.

If it is the case that the hybrid battery is used at “cold start” then perhaps 12V CCA might not be as important as with other vehicles, but even so I am not sure I would like to rely on a device that may or may not be charged depending upon how you have been using the braking system.

 

[Moonan]

Hi Colin,
As in my previous post, I am not yet very knowledgeable on this Mazda, but I have driven "mild hybrid" vehicles for a while, and this is what I have worked out so far (please any real expert chime in and correct me where I have worked it out wrong!)...
A vehicle can be claimed to be a "mild hybrid" if the alternator has a clutch, which does the following 3 things:
1. Disengages during normal driving unless the battery needs a top-up, to reduce load on the engine and so (marginally) save fuel;
2. Engages at any time that the battery needs a top-up, so as to keep it charged;
3. Engages during braking / deceleration in order to provide some "drag" on the engine (help the deceleration & reduce brake friction / wear) and also to utilise ("recover") some of the energy - that would otherwise be lost to heat in the brakes - to charge the battery (and so not use any fuel in this charging, providing further marginal savings).

Cars that only have the first two of these are said to have "smart alternators", but cars with all three can claim to be mild hybrids.

Now mild hybrids can use any battery system they like, and typically can operate with their normal 12V battery or they can be 24V (as the Mazda), or 48V as in newer designs from VW, Volvo etc).
For a car to be a "proper" hybrid there should be some active engine-assist from the electrical source (e.g. Toyota hybrids) but the various flavours of mild hybrids can provide any benefit from "just providing free battery charging" through to specifically operating the starter and pushing the engine into rev-matching during gear changes etc.
Some manufacturers barely (if at all) make any fuss about these systems, particularly the 12V ones, it is just one more little thing they do to meet the ever-tightening efficiency requirements (lead by EU). For example, my 2017 Audi has an instantaneous fuel-use indicator on the dash, which moves below zero and turns green under braking. This is the only indication that it is a "mild hybrid". Very mild, it is just telling me it has engaged the alternator clutch which is charging the battery with energy from deceleration and so providing an instantaneous "negative" fuel use.

The CX-30 (with X 20 engine) uses the Mazda M-Hybrid system which does the following:
1. There is an integrated starter generator connected to a 24V Lithium battery. This is belt driven and has a clutch so as to only engage when needed. There is no 12V alternator nor starter motor as far as I know..
2. The clutch on this device operates as I described in the list at the top of this long post when the car is going, it also engages to act as a starter motor (cold starts and i-stop functions), and as engine assist in limited other cases (rev-matching in MT gear changes are described somewhere).
3. There is a 24V/12V DC-DC converter. This provides charge to the regular 12V battery, as-needed, from the 24V lithium battery. Note that the 24V battery will always have enough power for this as it is not only charged by regenerative braking but also when the computer decides that the voltage is a bit low and it needs a top-up. If you want reassurance about this then watch the energy flow display during normal driving and you will see this combined flow from the engine to the front wheels and also through the displayed clutch to the battery from time to time (in my experience, only when the lithium battery shows 2 bars or less of charge).

Sorry for the very long-winded description, but this is why I asked my original question in my first post, and why I don't think the CCA are too important in the 12V battery, as long it has enough energy storage (Ah) to be able to turn on all of the systems necessary to instruct the 24V system to start the car!

Hope this helps in some small way.

As a reference for you regarding the 12V battery, here is a photo showing the rating details of mine (55Ah, 335 CCA), Japan-built CX-30 X-20 engine (Oz spec).

 

[ASH8]

in many cases this is the ISSUE...
Not a fault...BUT..

1. When a keyless transmitter (yours) is nearby the vehicle, it may wake up the vehicle from the sleeping mode, triggering a parasitic draw higher than 1A which may cause a battery drainage.
So make sure your Key Transmitter is at least 8 metres (25 feet) from car inside house.

2. Welcome Lamp deactivation

DEALER CAN DO No 2...BUT YOU MUST ASK THEM TO DEACTIVATE Welcome Lamp via MDARS..

 

[ColinW]

Hi Colin,
As in my previous post, I am not yet very knowledgeable on this Mazda, but I have driven "mild hybrid" vehicles for a while, and this is what I have worked out so far (please any real expert chime in and correct me where I have worked it out wrong!)...
A vehicle can be claimed to be a "mild hybrid" if the alternator has a clutch, which does the following 3 things:
1. Disengages during normal driving unless the battery needs a top-up, to reduce load on the engine and so (marginally) save fuel;
2. Engages at any time that the battery needs a top-up, so as to keep it charged;
3. Engages during braking / deceleration in order to provide some "drag" on the engine (help the deceleration & reduce brake friction / wear) and also to utilise ("recover") some of the energy - that would otherwise be lost to heat in the brakes - to charge the battery (and so not use any fuel in this charging, providing further marginal savings).

Cars that only have the first two of these are said to have "smart alternators", but cars with all three can claim to be mild hybrids.

Now mild hybrids can use any battery system they like, and typically can operate with their normal 12V battery or they can be 24V (as the Mazda), or 48V as in newer designs from VW, Volvo etc).
For a car to be a "proper" hybrid there should be some active engine-assist from the electrical source (e.g. Toyota hybrids) but the various flavours of mild hybrids can provide any benefit from "just providing free battery charging" through to specifically operating the starter and pushing the engine into rev-matching during gear changes etc.
Some manufacturers barely (if at all) make any fuss about these systems, particularly the 12V ones, it is just one more little thing they do to meet the ever-tightening efficiency requirements (lead by EU). For example, my 2017 Audi has an instantaneous fuel-use indicator on the dash, which moves below zero and turns green under braking. This is the only indication that it is a "mild hybrid". Very mild, it is just telling me it has engaged the alternator clutch which is charging the battery with energy from deceleration and so providing an instantaneous "negative" fuel use.

The CX-30 (with X 20 engine) uses the Mazda M-Hybrid system which does the following:
1. There is an integrated starter generator connected to a 24V Lithium battery. This is belt driven and has a clutch so as to only engage when needed. There is no 12V alternator nor starter motor as far as I know..
2. The clutch on this device operates as I described in the list at the top of this long post when the car is going, it also engages to act as a starter motor (cold starts and i-stop functions), and as engine assist in limited other cases (rev-matching in MT gear changes are described somewhere).
3. There is a 24V/12V DC-DC converter. This provides charge to the regular 12V battery, as-needed, from the 24V lithium battery. Note that the 24V battery will always have enough power for this as it is not only charged by regenerative braking but also when the computer decides that the voltage is a bit low and it needs a top-up. If you want reassurance about this then watch the energy flow display during normal driving and you will see this combined flow from the engine to the front wheels and also through the displayed clutch to the battery from time to time (in my experience, only when the lithium battery shows 2 bars or less of charge).

Sorry for the very long-winded description, but this is why I asked my original question in my first post, and why I don't think the CCA are too important in the 12V battery, as long it has enough energy storage (Ah) to be able to turn on all of the systems necessary to instruct the 24V system to start the car!

Hope this helps in some small way.

As a reference for you regarding the 12V battery, here is a photo showing the rating details of mine (55Ah, 335 CCA), Japan-built CX-30 X-20 engine (Oz spec). View attachment 1072

Hi Moonan,

Many thanks for your post, sorry it has taken me some time to reply, due to various Covid restrictions I have not been using the car very much, so had nothing useful to say. I still don’t really, but have a few observations. I have low confidence in this vehicle since as I mentioned it failed the day I took delivery, and I have not had a satisfactory technical explanation of the cause. I guess if I were driving it more this might not be the case.

I have become paranoid about the possibility of the battery going flat, so much so that I have installed a Bluetooth battery monitor, it has a small 1mA drain so should not kill the battery. I can see that the hybrid battery is used during i-stop, in fact it is quite interesting. With the engine stopped, under i-stop, the 12 volt battery is still being charged at around 14 volts; presumably from the hybrid battery through the DC-DC converter.

When the engine is restarted, via i-stop, there is no noticeable voltage drop, the transition is seamless. When the engine is started from cold I see a voltage drop on the 12 V system, which leads me suspect that the 12 volt battery is used for cold starts, and to further surmise that the 24 volt system is not enabled until after engine start. Below are a couple of shots of the engine cold start:

The first image is with an initial battery voltage around 12 V, and the second is after I deliberately ran the battery down to around 11.4 V. It is a pity that I have no idea what a cranking sequence looks like on a car with just a 12 volt system. My assumptions of what is happening may be completely wrong so I would welcome your comments.

Regards,
Colin.

 

[ASH8]

I would be careful about relying on any BT aftermarket device as 'accurate' diagnostics meter.

IF you deliberately run down your 12V (I guess as you did not say by leaving headlamps on?) the system is not going to top up from 24V until you start and Drive your car it's not an always active always on system.

A CCA crank and then stop and show results is somewhat meaningless as obviously the next CCA is going to be lower every time if you have not moved your car (driven it).

As I said previously (from Mazda) if your ''key module'' is close to your car inside house a 1A parasitic draw can flatted the Battery in a week.

As for the Dealer delivering your new car and experiencing a flat battery system Mazda Dealers were warned on the storage of Hybrid new cars on showroom floor and or in storage and how batteries will drain (see Key Fob Module distance).

Now whether the Dealer read the Bulletin is another matter, Mazda Dealers are still 'learning' this system and it is still considered new to them.
They also have (had) the old i-eloop 'capacitor' energy storage system and i-stop is not new for Mazda.

I can only suggest you stay in-contact with Dealer and perhaps next service insist they connect you car to MDARS Diagnostics and see if JAPAN has released any software updates for your car control modules like BCM, ECU, this can ONLY be done via a Dealer.
Do not ask your Service Adviser 'if' there are updates as in most cases they will not know UNTIL car is physically connected to MDARS and cloud service.

Again if you are only driving car short distance and key module is less than 25 feet from car it will flatten battery fast.
An easy test, if you are staying home for long periods AFTER a long car drive/use, wrap your key in aluminium foil (well) and see if this stops any parasitic draw down for you as this should stop car staying in awake mode status, unwrap when you need to use car.

EDIT: Car goes to sleep when it can not communicate with 'Key Fob' after 10 minutes of non use, IF key module is too close it is always active and draws down battery, Mazda 'may' change this IF it is the known cause of too many issues (just suggesting) these changes are done through MDARS updates by Mazda Dealer only.

 

[ASH8]

Here is Mazda's all new MDARS User Guide for Mazda Dealers only, first started in 2019 (BP Mazda 3).
You can download if you want (not certain how long my link will be active as Mega are changing policies).

It is of really no use to Mazda Owners but the 52 page PDF (2.6 MB) will give you an understanding of current car manufacturers Diagnostics, any updated software (if needed) is now cloud base (MMC Japan) and Only through a Mazda Dealer portal with a Mazda VCM II Passthrough and a Windows 10 PC with MDARS Installed on said PC.
MDARS is a Bosch 'base' system.

Most Mazda Mechanics (sorry technicians) are familiar with MDARS, some older guys have some reluctance as some broke a few expensive BCM's (Body Control Module) on BP Mazda 3 last year in 'learning of' new systems and fixing software or known new car model issues.
But this system is still new, depending on size of Dealership and new car volume some do not get to use it very often.

For any owner (IMO) the Following is Important...
Unfortunately many Mechanics have the ''if it ain't broke why fix it attitude'', Every new Mazda and car in for Service 'should be' connected live to MDARS via a laptop and check to see IF that car they are servicing has any software/firmware Updates and to run these correctly, but as I said many do not until a problem may occur with customer later.
If I was an owner going for a Service I would insist at car ''check in'' to Service Advisor to get a physical screenshot printout of the technicians access to MDARS and the checking of for any software updates (there are about 5 different Modules that 'could' have new updates at anytime) pertaining to your car and your cars VIN (number).

Not all changes are issued to Dealers via TSB's and even IF they are issued did the Tech read them and recalls them?, a live MDARS check eliminates any unforeseen memory lapses.

Frankly today it should be mandatory for the owner to have a hard copy and noted on or a similar update verification on RO (Repair Order) or owner Repair Invoice, don't get me wrong many great Mazda Dealer Service Departments do this already, many do not and I would personally never take a service advisors word for it that these systems are or were checked. Software updates do not always show any car behavioural or visual experience to the owner when they drive car as these are Systems updates.

Ford now no longer affiliated with Mazda in anyway also has their own FDRS.

MDARS User Guide .PDF

 

[sc489]

Can the 12V battery be charged using a standard battery charger designed for stop / start engines e.g. I have a CTEK CT5?

 

[ASH8]

yes

 

[ColinW]

I would be careful about relying on any BT aftermarket device as 'accurate' diagnostics meter.

IF you deliberately run down your 12V (I guess as you did not say by leaving headlamps on?) the system is not going to top up from 24V until you start and Drive your car it's not an always active always on system.

A CCA crank and then stop and show results is somewhat meaningless as obviously the next CCA is going to be lower every time if you have not moved your car (driven it).

As I said previously (from Mazda) if your ''key module'' is close to your car inside house a 1A parasitic draw can flatted the Battery in a week.

As for the Dealer delivering your new car and experiencing a flat battery system Mazda Dealers were warned on the storage of Hybrid new cars on showroom floor and or in storage and how batteries will drain (see Key Fob Module distance).

Now whether the Dealer read the Bulletin is another matter, Mazda Dealers are still 'learning' this system and it is still considered new to them.
They also have (had) the old i-eloop 'capacitor' energy storage system and i-stop is not new for Mazda.

I can only suggest you stay in-contact with Dealer and perhaps next service insist they connect you car to MDARS Diagnostics and see if JAPAN has released any software updates for your car control modules like BCM, ECU, this can ONLY be done via a Dealer.
Do not ask your Service Adviser 'if' there are updates as in most cases they will not know UNTIL car is physically connected to MDARS and cloud service.

Again if you are only driving car short distance and key module is less than 25 feet from car it will flatten battery fast.
An easy test, if you are staying home for long periods AFTER a long car drive/use, wrap your key in aluminium foil (well) and see if this stops any parasitic draw down for you as this should stop car staying in awake mode status, unwrap when you need to use car.

EDIT: Car goes to sleep when it can not communicate with 'Key Fob' after 10 minutes of non use, IF key module is too close it is always active and draws down battery, Mazda 'may' change this IF it is the known cause of too many issues (just suggesting) these changes are done through MDARS updates by Mazda Dealer only.

Ash,

Thanks for your replies on this thread, particularly the two most recent.

I agree with you about being careful about the Bluetooth device, and for the sake of anyone reading this I would recommend use with caution. Particularly since, as sold, the device does not have an inline fuse and is connected directly across the battery. Further any results obtained by such a device should be treated as indicative rather than definitive.

The CCA test was to try and get some idea about when the 24 volt system becomes active. There was some contention that it was involved in a “cold” start but I think the results indicate that this is not the case. There was no real objective in “running” down the battery other than to get some idea how quickly this can occur just with the vehicle in “ACC” mode and lights off. I was also curious to see if the car would actually start.

The “Key Fob Module” issue you mention I was already aware off, but even before that both keys were being kept in Faraday bags some distance from the vehicle, to mitigate the potential “relay theft” issue.

The information you gave regarding MDARS is invaluable. I was not aware of this Diagnostic system, nor did I realise that there are multiple control modules. I imagine that the vehicle system needs to be considered at a build level to insure compatibility among the various software versions on each module. From what you have said it seems obvious that as part of any Service the vehicle should be connected to MDARS and indeed a report of the MDARS output would be, to me, of some reassurance.

I wish I could get the equivalent of a “Haynes manual” so that I might get a better understanding of how this machine is built. I feel a bit like a “mug punter” at the moment, I selected this CX-30 because I was interested in the “X” engine and had read quite a lot about that before I bought it. I knew nothing about the mild hybrid system and have only learnt from posts; particularly on this thread.

Regards,
Colin.

 

[Kilo Watt]

The smart key can be disabled and turned into a "dumb" one.

I did this for the spare key, so the battery doesn't run out and it works. It becomes a normal key, the remote still works and you need to keep it in contact with the start/stop button to start the engine.

 

[Glencraig]

Went out to my CX-30 GT Sport Tech yesterday morning, to take it to my local dealers for the freezing mirrors issue (qv) but it wouldn’t start at all, couldn’t even open the boot to get my jump leads out.
Battery voltage was down to about 4v. Got jump started by a neighbour but loads of warnings cycling through in the middle of the Speedo all the way to the dealers.
My wife’s key was in her handbag near a window within arm’s reach of the car. Reading some of the above posts, sounds like this may have been the cause of all our problems.

 

[ASH8]

Key Too close from what I can see, arms reach the car is thinking you are about to start engine
One can be creative to shield key in handbag close to car, plus she will say how clever you are

I generally don't re-read what I write, but guys be careful with ANY after market Accessory you add inside your car or under bonnet/hood, or towbar, todays cars and Mazda's are so technical every single piece of wiring is basically monitored by cars operating system and you will throw a DTC (Diagnostic Trouble Code) that you will not know about unless serious enough for as CEL light.
99% of all DTC's today can only be cleared by a Mazda Dealer and MDARS.
Get too many and your car will go into limp home mode.
Anything that draws a current while driving, or plugs into 12V outlet, like a separate phone charger. or whatever.
Mazda Dealer will give you advice on what to do if not sure.

 

[gerntz]

The smart key can be disabled and turned into a "dumb" one.

I did this for the spare key, so the battery doesn't run out and it works. It becomes a normal key, the remote still works and you need to keep it in contact with the start/stop button to start the engine.

Thanks. Interesting.

But how long does it take for the FOB battery to run down if you don't make it dumb? A year? My FOB batteries on various cars have lasted well over a year with no action.

 

[detailcarguy]

Key Too close from what I can see, arms reach the car is thinking you are about to start engine
One can be creative to shield key in handbag close to car, plus she will say how clever you are

I generally don't re-read what I write, but guys be careful with ANY after market Accessory you add inside your car or under bonnet/hood, or towbar, todays cars and Mazda's are so technical every single piece of wiring is basically monitored by cars operating system and you will throw a DTC (Diagnostic Trouble Code) that you will not know about unless serious enough for as CEL light.
99% of all DTC's today can only be cleared by a Mazda Dealer and MDARS.
Get too many and your car will go into limp home mode.
Anything that draws a current while driving, or plugs into 12V outlet, like a separate phone charger. or whatever.
Mazda Dealer will give you advice on what to do if not sure.

thank you for posting that.. with all due respect I am getting annoyed by people not understanding or knowing that vehicles now days are all computer controlled and monitored and if something is changed that interferes with that the software on the computer system dosent know what to do and assumes a fault and like you said goes into a fault protection mode /limp home mode.. I have worked with allot of professional licensed mechanics and I have heard time after time after market stuff causing problems with the electronics... cars are not the way they use to be and you cant be MR fix it anymore.