Auto Start/Stop Not Working

[Nac]

I've read that there needs to be certain criteria met in order for this feature to work. And I've checked for everything except the battery. I have a hunch that there isn't enough juice in the battery or there might be something wrong with it.

There are many ISG permissive conditions see charts below, some are impossible to check without a diagnostic computer connected to the vehicle. The ISG complex logic is easily rendered inactive by only 1 of the many permissive signals not being satisfied.

 

[Caravan3]

it only takes milliamps to maintain the electronics of the stop/start function which is a very low current draw compared to cranking over the engine.

If that is the case then the battery would not have any need to to be at its optimum charge for the stop /start to always function after the vehicle starts
The battery needing to be at a very high point of charge is what the KIA technicians keep referring to as the (sensors , parasite drains bad earth aside ) main cause for the system not functioning.
The alternator can have a regulated feed back to prevent overcharge (the alternator already has this ) but a slightly higher level to compensate for any drains which lets the battery drop below the optimum charge KIA maintains as the main cause for the stop/start not working .

 

[Nac]

If that is the case then the battery would not have any need to to be at its optimum charge for the stop /start to always function after the vehicle starts
The battery needing to be at a very high point of charge is what the KIA technicians keep referring to as the (sensors , parasite drains bad earth aside ) main cause for the system not functioning.
The alternator can have a regulated feed back to prevent overcharge (the alternator already has this ) but a slightly higher level to compensate for any drains which lets the battery drop below the optimum charge KIA maintains as the main cause for the stop/start not working .

"If that is the case then the battery would not have any need to to be at its optimum charge for the stop /start to always function after the vehicle starts"

Really? The battery still has to provide up to 1000 amps to crank the starter to start the car after it is shut down by auto stop/start. You do realize the alternator stops producing electricity when the engine stops and the battery is all that is left to start the car.

Starting a car is significantly discharges the battery. Ever have a car fail to start? How many times could you crank the engine before the battery had insufficient energy to turn over the engine? Sometimes the electronics still work, even the radio might work, but the car will not crank because there is not enough energy in the battery to spin the starter.

That is what the engineers are trying to prevent by monitoring the battery charge level and inhibiting auto stop/start from causing further extreme discharging of an already discharged battery.

This is not a design issue, it is working as designed to prevent being stranded with a battery that can no longer start the car.

Your answer has me thinking you are not that knowledgeable regarding automotive electrical /electronic systems and their capabilities.

 

[Caravan3]

"If that is the case then the battery would not have any need to to be at its optimum charge for the stop /start to always function after the vehicle starts"

Really? The battery still has to provide up to 1000 amps to crank the starter to start the car after it is shut down by auto stop/start. You do realize the alternator stops producing electricity when the engine stops and the battery is all that is left to start the car.

Starting a car is significantly discharges the battery. Ever have a car fail to start? How many times could you crank the engine before the battery had insufficient energy to turn over the engine? Sometimes the electronics still work, even the radio might work, but the car will not crank because there is not enough energy in the battery to spin the starter.

That is what the engineers are trying to prevent by monitoring the battery charge level and inhibiting auto stop/start from causing further extreme discharging of an already discharged battery.

This is not a design issue, it is working as designed to prevent being stranded with a battery that can no longer start the car.

Your answer has me thinking you are not that knowledgeable regarding automotive electrical /electronic systems and their capabilities.

Clearly you completely missed the point about optimum battery requirements and the respective loads placed at different stages throughout the operation of the vehicle from the initial cranking requirement to the other stages needed to sustain all other electrical features of the vehicle in tandem .
You make points about the call on a battery to start a vehicle but miss the point about the role of the battery and the necessity for the battery to be charged by the regulated feed from the alternator to the battery - you went off on a tangent that has nothing to do with the points raised .
You provide the same repetitive illogical failure to address the fact that so many drivers have been told by KIA dealerships that their battery is the reason why the stop/start isn't working - put simply , do you believe that drivers with new vehicles who report the failure of the stop/start function and who have driven for significant enough distances to maintain a battery at its optimum performance are all victims of a problematic battery ?

______________________________

 

[Tellthemride]

Clearly you completely missed the point about optimum battery requirements and the respective loads placed at different stages throughout the operation of the vehicle from the initial cranking requirement to the other stages needed to sustain all other electrical features of the vehicle in tandem .
You make points about the call on a battery to start a vehicle but miss the point about the role of the battery and the necessity for the battery to be charged by the regulated feed from the alternator to the battery - you went off on a tangent that has nothing to do with the points raised .
You provide the same repetitive illogical failure to address the fact that so many drivers have been told by KIA dealerships that their battery is the reason why the stop/start isn't working - put simply , do you believe that drivers with new vehicles who report the failure of the stop/start function and who have driven for significant enough distances to maintain a battery at its optimum performance are all victims of a problematic battery ?

I believe it is a combination of Kia tolerance requirements set too high for the ISG system operating conditions, or KIA OEM batteries for the Telluride are crap and cannot maintain a full charge for a very long lifespan.

When I charge my battery to 100%, ISG still sometimes does not activate at every stop, even after the engine reaches optimal temp. I also monitor my battery voltage when the engine is off. At 12.5 or 12.3 volts, should be normal charge levels for the ISG to function as intended.

I’ve only had the car for 3 years, so if it can’t maintain a full charge after hours of weekend driving, enough to activate ISG, battery quality is petty bad if that is the issue. Kind of like how iPhone batteries only function at 80% maximum capacity relative to when new after owning for 2 years.

Compared to other cars I’ve rented and cars I see on the road where ISG works every stop I’d say the ISG function on my 2020 Telluride is non-existent.

I do plan to change to a third party battery in the next year or two, and will report back if ISG functionality is restored.

 

[Nac]

Clearly you completely missed the point about optimum battery requirements and the respective loads placed at different stages throughout the operation of the vehicle from the initial cranking requirement to the other stages needed to sustain all other electrical features of the vehicle in tandem .
You make points about the call on a battery to start a vehicle but miss the point about the role of the battery and the necessity for the battery to be charged by the regulated feed from the alternator to the battery - you went off on a tangent that has nothing to do with the points raised .
You provide the same repetitive illogical failure to address the fact that so many drivers have been told by KIA dealerships that their battery is the reason why the stop/start isn't working - put simply , do you believe that drivers with new vehicles who report the failure of the stop/start function and who have driven for significant enough distances to maintain a battery at its optimum performance are all victims of a problematic battery ?

"Clearly you completely missed the point about optimum battery requirements and the respective loads placed at different stages throughout the operation of the vehicle from the initial cranking requirement to the other stages needed to sustain all other electrical features of the vehicle in tandem ."

I agree, I clearly missed a point you never made. If you read closely you can see that I stated the battery's electronic loads were very small compared the cranking load.

"You make points about the call on a battery to start a vehicle but miss the point about the role of the battery and the necessity for the battery to be charged by the regulated feed from the alternator to the battery - you went off on a tangent that has nothing to do with the points raised."

I did not miss that point, I ignored it because I was only addressing the first ill-considered statement you made (If that is the case then the battery would not have any need to to be at its optimum charge for the stop /start to always function after the vehicle starts).

Based on your statements it's apparent you believe the alternator is not properly charging the battery and is the cause for the electronic circuits of the ISG system to not function, which I find imprudent. What is the alternators output? What is the maximum current load on the car in running condition, off condition, and starting condition? How many amps are left for charging the battery with the car in a running condition? If you don't know the answers to these you are guessing, just like the Kia technicians.

"You provide the same repetitive illogical failure to address the fact that so many drivers have been told by KIA dealerships that their battery is the reason why the stop/start isn't working

Do you believe the Kia technicians are correct? What did they connect some instrumentation to the car? What parameters did they measure? Did they just say its the battery because that makes the customer go away? It appears you take the Kia technicians word for this being the issue, I don't.

put simply , do you believe that drivers with new vehicles who report the failure of the stop/start function and who have driven for significant enough distances to maintain a battery at its optimum performance are all victims of a problematic battery?"

What is the significant enough distance driven by these vehicles? How frequently are they driven? What is the actual duty cycle for the vehicle to maintain optimum battery performance (run vs off time)? If you don't know the answers to these you are guessing what "driven significant enough distance" is. After this significant distance driven did they leave the vehicle parked long enough to drain the battery to a point where ISG disables? If you don't know the answers to these questions you are guessing.

If you look at the Kia chart I provided you will see there 15 signals that disable ISG (and 8 that cause an immediate restart.) So of the 15 how many did the Kia techs measure to see which of them are the cause?

As a point of reference I owned a 2018 Stinger. ISG worked for about 2 months then quit working (I was happy it quit). I drove that car daily for over a year and ISG did not engage once. I then dove the car from NY to Tennessee (14 hours) and like magic the ISG started working again. About 2 weeks after the trip the ISG stopped working (I was again happy it quit).

Your original post concluded (though a half-assed attempt at a logic chain): "...there is an inherent shortfall in the KIA alternator to sustain the necessary charge to the battery to maintain the stop/start function...."

If you can't answer the majority of the questions above regarding the alternator, the vehicle duty cycle etc; you are guessing and pretending its logic.

 

[Caravan3]

"Clearly you completely missed the point about optimum battery requirements and the respective loads placed at different stages throughout the operation of the vehicle from the initial cranking requirement to the other stages needed to sustain all other electrical features of the vehicle in tandem ."

I agree, I clearly missed a point you never made. If you read closely you can see that I stated the battery's electronic loads were very small compared the cranking load.

"You make points about the call on a battery to start a vehicle but miss the point about the role of the battery and the necessity for the battery to be charged by the regulated feed from the alternator to the battery - you went off on a tangent that has nothing to do with the points raised."

I did not miss that point, I ignored it because I was only addressing the first ill-considered statement you made (If that is the case then the battery would not have any need to to be at its optimum charge for the stop /start to always function after the vehicle starts).

Based on your statements it's apparent you believe the alternator is not properly charging the battery and is the cause for the electronic circuits of the ISG system to not function, which I find imprudent. What is the alternators output? What is the maximum current load on the car in running condition, off condition, and starting condition? How many amps are left for charging the battery with the car in a running condition? If you don't know the answers to these you are guessing, just like the Kia technicians.

"You provide the same repetitive illogical failure to address the fact that so many drivers have been told by KIA dealerships that their battery is the reason why the stop/start isn't working

Do you believe the Kia technicians are correct? What did they connect some instrumentation to the car? What parameters did they measure? Did they just say its the battery because that makes the customer go away? It appears you take the Kia technicians word for this being the issue, I don't.

put simply , do you believe that drivers with new vehicles who report the failure of the stop/start function and who have driven for significant enough distances to maintain a battery at its optimum performance are all victims of a problematic battery?"

What is the significant enough distance driven by these vehicles? How frequently are they driven? What is the actual duty cycle for the vehicle to maintain optimum battery performance (run vs off time)? If you don't know the answers to these you are guessing what "driven significant enough distance" is. After this significant distance driven did they leave the vehicle parked long enough to drain the battery to a point where ISG disables? If you don't know the answers to these questions you are guessing.

If you look at the Kia chart I provided you will see there 15 signals that disable ISG (and 8 that cause an immediate restart.) So of the 15 how many did the Kia techs measure to see which of them are the cause?

As a point of reference I owned a 2018 Stinger. ISG worked for about 2 months then quit working (I was happy it quit). I drove that car daily for over a year and ISG did not engage once. I then dove the car from NY to Tennessee (14 hours) and like magic the ISG started working again. About 2 weeks after the trip the ISG stopped working (I was again happy it quit).

Your original post concluded (though a half-assed attempt at a logic chain): "...there is an inherent shortfall in the KIA alternator to sustain the necessary charge to the battery to maintain the stop/start function...."

If you can't answer the majority of the questions above regarding the alternator, the vehicle duty cycle etc; you are guessing and pretending its logic.

The criteria you mention exemplified by the System Operating Conditions has one very basic common denominator - dependency on a battery at optimum performance - every other variant is reliant and inter dependent
You go on ...

What is the significant enough distance driven by these vehicles? How frequently are they driven? What is the actual duty cycle for the vehicle to maintain optimum battery performance (run vs off time)?

I won't be wasting my time answering these side stepping distractions .

Thanks for the information about your long 14 hour drive - yep of course the system kicked in because yes there is an inherent failure to have the battery brought up to optimum performance on normal drives - as your point of reference highlighted .

 

[Caravan3]

I believe it is a combination of Kia tolerance requirements set too high for the ISG system operating conditions, or KIA OEM batteries for the Telluride are crap and cannot maintain a full charge for a very long lifespan.

When I charge my battery to 100%, ISG still sometimes does not activate at every stop, even after the engine reaches optimal temp. I also monitor my battery voltage when the engine is off. At 12.5 or 12.3 volts, should be normal charge levels for the ISG to function as intended.

I’ve only had the car for 3 years, so if it can’t maintain a full charge after hours of weekend driving, enough to activate ISG, battery quality is petty bad if that is the issue. Kind of like how iPhone batteries only function at 80% maximum capacity relative to when new after owning for 2 years.

Compared to other cars I’ve rented and cars I see on the road where ISG works every stop I’d say the ISG function on my 2020 Telluride is non-existent.

I do plan to change to a third party battery in the next year or two, and will report back if ISG functionality is restored.

I believe it is a combination of Kia tolerance requirements set too high for the ISG system operating conditions, or KIA OEM batteries for the Telluride are crap and cannot maintain a full charge for a very long lifespan.

When I charge my battery to 100%, ISG still sometimes does not activate at every stop, even after the engine reaches optimal temp. I also monitor my battery voltage when the engine is off. At 12.5 or 12.3 volts, should be normal charge levels for the ISG to function as intended.

I’ve only had the car for 3 years, so if it can’t maintain a full charge after hours of weekend driving, enough to activate ISG, battery quality is petty bad if that is the issue. Kind of like how iPhone batteries only function at 80% maximum capacity relative to when new after owning for 2 years.

Compared to other cars I’ve rented and cars I see on the road where ISG works every stop I’d say the ISG function on my 2020 Telluride is non-existent.

I do plan to change to a third party battery in the next year or two, and will report back if ISG functionality is restored.

Tellthemride you say ..When I charge my battery to 100%, ISG still sometimes does not activate at every stop, even after the engine reaches optimal temp. I also monitor my battery voltage when the engine is off. At 12.5 or 12.3 volts, should be normal charge levels for the ISG to function as intended.

How are you charging the battery - a quick charge or a trickle system , or by longer drives than normal then measuring the battery

______________________________

 

[Nac]

The criteria you mention exemplified by the System Operating Conditions has one very basic common denominator - dependency on a battery at optimum performance - every other variant is reliant and inter dependent
You go on ...

What is the significant enough distance driven by these vehicles? How frequently are they driven? What is the actual duty cycle for the vehicle to maintain optimum battery performance (run vs off time)?

I won't be wasting my time answering these side stepping distractions .

Thanks for the information about your long 14 hour drive - yep of course the system kicked in because yes there is an inherent failure to have the battery brought up to optimum performance on normal drives - as your point of reference highlighted .

"The criteria you mention exemplified by the System Operating Conditions has one very basic common denominator - dependency on a battery at optimum performance - every other variant is reliant and inter dependent"

The criteria are not dependent on optimum performance of the battery nor are they interdependent..
Item: Switch (Seatbelt/Door/Hood) Condition: Fastened/Closed/Closed these will work adequately with the battery in non-optimal condition and the hood switch is not interdependent on the seatbelt, they are wholly separate. Simply put you are wrong.

"What is the significant enough distance driven by these vehicles? How frequently are they driven? What is the actual duty cycle for the vehicle to maintain optimum battery performance (run vs off time)?
I won't be wasting my time answering these side stepping distractions"

You wont waste time answering or you can't answer because you don't know. The answers to these side stepping distractions are what you need to prove your theory that

"there is an inherent shortfall in the KIA alternator to sustain the necessary charge to the battery to maintain the stop/start function."

I understand you not wanting to answer these questions because it would reveal your weak, jump to cause, without facts or evidence troubleshooting method.

"Thanks for the information about your long 14 hour drive - yep of course the system kicked in because yes there is an inherent failure to have the battery brought up to optimum performance on normal drives - as your point of reference highlighted."

Another assumption with no supporting facts or evidence; what is a "normal drive".

Your theory of an inherently weak alternator does not explain any tellurides the have ISG working the majority of the time (like my Wife's).

 

[G-931555]

Your theory of an inherently weak alternator does not explain any tellurides the have ISG working the majority of the time (like my Wife's).

Reply
She probably takes very long drives to get away from you lol

Every circuit in an electrical system IS interdependent except in circumstances where there is a secondary power source .The individual functions are circuit dependent from source ie battery.
The waffle about ...Switch (Seatbelt/Door/Hood) Condition: Fastened/Closed/Closed these will work adequately with the battery in non-optimal condition and the hood switch is not interdependent on the seatbelt, they are wholly separate. Simply put you are wrong.

Once again you have stated what I'D already stated earlier when I posed the question about everything other than the stop/start working without the battery being at optimum ...... did you miss that ???

I never stated that the alternator was inherently weak (though it could be ) ...I questioned the charge from the alternator perhaps not being correctly regulated and restricting the correct feedback ...a trickling effect which restricts and takes longer to bring the battery to optimum level. Tellthemride sort of implies this , though not directly when they mention the KIA tolerances - they may be referring to other .criteria but its a rational and plausible deduction in any context.

 

[Nac]

I believe it is a combination of Kia tolerance requirements set too high for the ISG system operating conditions, or KIA OEM batteries for the Telluride are crap and cannot maintain a full charge for a very long lifespan.

When I charge my battery to 100%, ISG still sometimes does not activate at every stop, even after the engine reaches optimal temp. I also monitor my battery voltage when the engine is off. At 12.5 or 12.3 volts, should be normal charge levels for the ISG to function as intended.

I’ve only had the car for 3 years, so if it can’t maintain a full charge after hours of weekend driving, enough to activate ISG, battery quality is petty bad if that is the issue. Kind of like how iPhone batteries only function at 80% maximum capacity relative to when new after owning for 2 years.

Compared to other cars I’ve rented and cars I see on the road where ISG works every stop I’d say the ISG function on my 2020 Telluride is non-existent.

I do plan to change to a third party battery in the next year or two, and will report back if ISG functionality is restored.

"I’ve only had the car for 3 years, so if it can’t maintain a full charge after hours of weekend driving, enough to activate ISG, battery quality is petty bad if that is the issue."

Factors impacting (reducing) battery life include, material quality, the climate where the battery is used(extreme hot/cold temperatures), "Start/Stop" technology starting the engine thousands of times over the life of a battery. Every time you start your car, it requires a huge amount of electrical power from your battery. If you have short commutes or frequent brief trips, the battery will not get fully charged leading to acid stratification and the battery condition will deteriorate faster. Instead of looking at a 5-year battery life, it can be reduced to as low as 3 years.

"When I charge my battery to 100%, ISG still sometimes does not activate at every stop, even after the engine reaches optimal temp."

ISG is a fickle bitch, all the following conditions need to be Satisfied for ISG to be enabled.

Switch (Seat belt/Door/Hood)	Fastened/Closed/Closed
Gear position	D/N
Vehicle speed	Entering 0 kph after driving over 5 kph (3.1mph).
Climate control system condition	FATC/MTC Satisfied (FATC = Fully Automatic Temperature Control) (MTC = Manual temp Control)
MPDS (Motor Driven Power Steering)	Less than 180 degrees
Battery condition Charge/Discharge performance	SOC > 68 % (SOC = State of Charge)
Engine coolant temperature	20 - 43 °C (68 -109.4°F)
Ambient air temperature	Ambient air temperature: -20 to 50°C (-4 to122°F)
Atmospheric pressure	More than 750 hPa (75 kph, 0.76 kg/cm²,10.88 psi)
Brake vacuum pressure	Less than -35 kpa (-0.36 kg/cm², -5.07 psi)
Incline condition	-5 to 12%

These conditions DISABLE ISG

Climate control system condition Blower MAX. / Front Defogger	ON
Battery condition Voltage	Insufficient charging and discharging performance (Battery condition is monitored by the battery sensor)

 

[Nac]

I never stated that the alternator was inherently weak (though it could be ) ...I questioned the charge from the alternator perhaps not being correctly regulated and restricting the correct feedback ...a trickling effect which restricts and takes longer to bring the battery to optimum level. Tellthemride sort of implies this , though not directly when they mention the KIA tolerances - they may be referring to other .criteria but its a rational and plausible deduction in any context.

Ok, I must have misread Post 15 below where it says "there is an inherent shortfall in the KIA alternator to sustain the necessary charge to the battery to maintain the stop/start function" somehow "shortfall in the Kia alternator" now means "the charge from the alternator perhaps not being correctly regulated and restricting the correct feedback ...a trickling effect which restricts and takes longer to bring the battery to optimum level."

I guess my mind reading skills were not working correctly when I read that.

I also have no clue what you mean by "perhaps not being correctly regulated and restricting the correct feedback ...a trickling effect which restricts and takes longer to bring the battery to optimum level "

Perhaps you could communicate in industry accepted electrical engineering terms so I can understand what you are attempting to communicate about the alternator, voltage regulator and charging the battery.

I would hate perpetuate "leaving tens of thousands of KIA drivers resorting to online forums to seek to unravel the mystery of the reason why their start/stop isn't working"

When the battery is put on a charger and charged fully the stop start in 99% of the cases will activate the stop start to function .
However the kia dealers continue to insist that the cause for the function not working is the battery not being 100% ,,,,lets apply logic here - if every other function in the vehicle dependent on the battery works as it should - why not the stop /start ,
This suggests that a higher demand is placed on the battery to maintain the stop/start - if that is so and the function doesn't work as it should (after sensors are checked and battery charged - then there is an inherent shortfall in the KIA alternator to sustain the necessary charge to the battery to maintain the stop/start function .
KIA has not addressed this problem leaving tens of thousands of KIA drivers resorting to online forums to seek to unravel the mystery of the reason why their start/stop isn't working
KIA needs to get this sorted as too many people have resigned themselves to being without a function which if working properly would save on fuel and be more environmentally friendly in the cities and large towns where it is more in use .

______________________________

 

[Caravan3]

Ok, I must have misread Post 15 below where it says "there is an inherent shortfall in the KIA alternator to sustain the necessary charge to the battery to maintain the stop/start function" somehow "shortfall in the Kia alternator" now means "the charge from the alternator perhaps not being correctly regulated and restricting the correct feedback ...a trickling effect which restricts and takes longer to bring the battery to optimum level."

I guess my mind reading skills were not working correctly when I read that.

I also have no clue what you mean by "perhaps not being correctly regulated and restricting the correct feedback ...a trickling effect which restricts and takes longer to bring the battery to optimum level "

Perhaps you could communicate in industry accepted electrical engineering terms so I can understand what you are attempting to communicate about the alternator, voltage regulator and charging the battery.

I would hate perpetuate "leaving tens of thousands of KIA drivers resorting to online forums to seek to unravel the mystery of the reason why their start/stop isn't working"

you don't believe the Kia technicians take on the battery being cited as the main reason either - you throw up conditions necessary for the system to work but offer no valid reason for the failures other than these conditions not being met by the conditional criteria ...the single biggest reason why batteries continually fall below optimum and creates the resultant typical customer response from KIA dealers , which is to charge the battery (usual short term fix because the underlying prob;em ie insufficient charge being generated to maintain optimum performance
Why is it the case that in almost every case the stop/start works after a battery being charged up - what strange set of the criteria conditions are suddenly and miraculously met that weren't being met before this divine intervention
Based on that I will reiterate my assertion that regardless of technical jargon which I too could regurgitate - I hold the base problem to be an inherent shortfall of the alternator /battery charging system to maintain the battery optimum level .

 

[Caravan3]

Nothing more to say on this forum - I wont be back

 

[Nac]

you don't believe the Kia technicians take on the battery being cited as the main reason either - you throw up conditions necessary for the system to work but offer no valid reason for the failures other than these conditions not being met by the conditional criteria ...the single biggest reason why batteries continually fall below optimum and creates the resultant typical customer response from KIA dealers , which is to charge the battery (usual short term fix because the underlying prob;em ie insufficient charge being generated to maintain optimum performance
Why is it the case that in almost every case the stop/start works after a battery being charged up - what strange set of the criteria conditions are suddenly and miraculously met that weren't being met before this divine intervention
Based on that I will reiterate my assertion that regardless of technical jargon which I too could regurgitate - I hold the base problem to be an inherent shortfall of the alternator /battery charging system to maintain the battery optimum level .

I lost you at "the single biggest reason why batteries continually fall below optimum and creates the resultant typical customer response from KIA dealers" it does not appear to be a complete sentence.

I do not believe there is anything wrong with the charging system, (Which according to Kia includes ECM, Battery, Alternator, Starter, Instrument Cluster, Ignition switch or start/stop button, Battery sensor, alternator regulator)

According to Kia the system is designed to operate as follows:
The charging system includes a battery, an alternator with a built-in regulator, and the charging indicator light and wire. The Alternator has eight built-in diodes, each rectifying AC current to DC current. Therefore, DC current appears at alternator "B" terminal.

In addition, the charging voltage of this alternator is regulated by the battery voltage detection system. The main components of the alternator are the rotor, stator, rectifier, capacitor brushes, bearings and V-ribbed belt pulley. The brush holder contains a built-in electronic voltage regulator.

Kia description of the Alternator Management System
Alternator management system controls the charging voltage set point in order to improve fuel economy, manage alternator load under various operating conditions, keep the battery charged, and protect the battery from over-charging. ECM controls generating voltage by duty cycle (charging control, discharging control, normal control) based on the battery conditions and vehicle operating conditions.

The system conducts discharging control when accelerating a vehicle. Vehicle reduces an alternator load and consumes an electric power from a battery.
The system conducts charging control when decelerating a vehicle. Vehicle increases an alternator load and charges a battery.

Kia's Alternator Specifications:
Rated voltage 13.5V , 180A
Speed in use 0 - 18,000rpm
Voltage regulator IC Regulator built in type
Default regulated voltage (V) [COM terminal] 14.09 - 14.91 (-35°C), 13.96 - 15.04 (140°C)

So the default regulated voltage output of the alternator (depending on temperature) is between 13.96v and 15.04v (14.5v mid range). which is fine for charging a 12v vehicle battery.

You keep concluding a shortfall in the charging and profess it needs to be higher so as to fast charge the battery, unfortunately this would excessively overcharge the battery and lead to at best early battery life failure or at worst a battery explosion.

My suspicion is the reason the ISG does not reliably work is because its a self defeating system.
It abuses the battery by stopping & starting the engine over and over. Starting a car is the deepest discharge mode for a car battery.
ISG monitors battery performance and disables it self when it detects low battery capacity (a condition it causes), which if unresolved will lead to failure to start the car (dead battery). Monitoring continues and when the battery is sufficiently recharged ISG begins this asinine cycle again. Deep discharge the battery multiple times by stopping/starting the engine till the monitor detects it has abused the battery enough and ISG disables itself.

I don't believe I could think of a better system to deliberately destroy batteries in the name of MPG.

The ISG system is stupid, its a marketing gimmick (because of how car MPG is tested & specified) that allows manufacturers to claim better MPG numbers on the big yellow sticker.

What ISG saves in gas is likely significantly outweighed by the fuel needed to mine or recycle lead, make sulfuric acid, manufacture plastic battery cases, run the manufacturing plant to build the batteries and destroy or recycle the dead batteries.

Batteries are not cheap how much is the gas savings over 3 years, hopefully enough to pay for an expensive new battery.

Your suggested solution of increasing the charge rate to the battery so ISG can deep discharge it more often would destroy batteries faster due to overcharging and promoting more ISG discharge cycles. Tens of thousands of KIA drivers should be happy when ISG stops working, its saving their battery from an early grave.

 

[Nac]

Nothing more to say on this forum - I wont be back

Bye!!

______________________________

 

[Nac]

Duplicate

 

[Smalls124]

I have a 2020 Telluride and it has been at the dealership for over a week now because the ISG stopped working. I have a second vehicle I can use so have opted to leave it until they figure it out. It worked for two years then stopped. I also don't care for the feature but am worried that whatever issue is preventing it from working can impact other things. After the usual spiel about the criteria, I pointed out that it statistically doesn't make sense that I would have met the criteria unfailingly for two years and then not once for the last six months. The dealership has concurred that something is wrong as they have made sure the criteria are met and still can't get it to work. They are doing what the all-powerful "Kia Tech Line" has instructed but the wait between responses from the Tech Line is ridiculous. I'll let you know what happens!

 

[Nac]

I have a 2020 Telluride and it has been at the dealership for over a week now because the ISG stopped working. I have a second vehicle I can use so have opted to leave it until they figure it out. It worked for two years then stopped. I also don't care for the feature but am worried that whatever issue is preventing it from working can impact other things. After the usual spiel about the criteria, I pointed out that it statistically doesn't make sense that I would have met the criteria unfailingly for two years and then not once for the last six months. The dealership has concurred that something is wrong as they have made sure the criteria are met and still can't get it to work. They are doing what the all-powerful "Kia Tech Line" has instructed but the wait between responses from the Tech Line is ridiculous. I'll let you know what happens!

Interesting that all criteria are met and it still does not work.

You are right about the wait time for kia tech line response; hopefully they figure it out. I am interested in what they find.

 

[beato1]

Hmm, so can we deduce that when ISG works, the battery is at 100% charged? But it stops working if battery is less than 100% charged? But that will be a very high parameter. How about say 80% charged —when there is still ample power to restart the car (to avoid being stranded)? I think ISG is designed to not kick in when battery reached a certain charged but still far from being discharged! Maybe they left a wide enough berth to avoid further discharging the battery (despite enough charge left—like 80 or 70%) in anticipation of more start and go that will lead to depletion of battery resulting to failure to start (stranded)! With this theory, we can then deduce that if ISG stops working, it doesn’t necessarily mean battery is going bad (tho it could be)—it just doesn’t meet the battery criteria. But if ISG is working, we can be assured that the battery is in excellent shape! In a way, ISG then is a good indicator of the state of charge of the battery! Just my two cents! Thanks!