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However, if that is true and sulphating is the problem they why are there lots of Kona EVs not suffering this problem?
Same reason that some people do NOT suffer from a failure to achieve NEDC range/mileage?
 

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Discussion Starter · #23 ·
There seems to be a major fault with the design of the car that causes a constant draw on the 12v
Yeah, nah, it doesn't sound even plausible. The LDC (that charges the 12V battery off the main battery) won't care what the motor, etc is doing. All energy comes from the traction battery and the 12V system only needs a few hundred watts. In any case, when driving, aux battery charging is fairly minimal with the 196 update, rather it mostly just avoids depleting it.

At the risk of boring everyone yet again with my graph, leaving the hatch ajar rapidly causes a significant depletion of the aux battery. And, to add insult to injury prevents the scheduled charging events from starting. In this short test I've lost 0.5 V in a matter of 40 minutes and it only bounced back halfway when the hatch was closed. My aux battery is 2.5 years old now and still sits at 13.0 V when parked.

View attachment 144122
Did you leave the car On on Park while this test was going on?
I cant get my OBD device to connect to the ECU when the car is off but turning the car on would put a load on the 12V no?
So how do i get to the point where i can make this graph in my car?
 

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There seems to be a major fault with the design of the car that causes a constant draw on the 12v


Did you leave the car On on Park while this test was going on?
I cant get my OBD device to connect to the ECU when the car is off but turning the car on would put a load on the 12V no?
So how do i get to the point where i can make this graph in my car?
I think that is the graph from a BM2 device that is connected to the battery - at least that is what my one looks like.
 

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Same reason that some people do NOT suffer from a failure to achieve NEDC range/mileage?
That does not make sense. Either the cars do not have their 12v battery charging correctly or they do charge correctly. The driver cannot influence that. Moreover, as said in a previous post, the battery is actually being charged at about 14.7v every 4hrs ish, which should be fine - and appears to be in my car which displays the same charging characteristic as in post 17.
 

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That does not make sense.
It makes perfect sense. So what you actually meant there was 'it doesn't make sense to me'.

I'll spell it out;-
1) A BEV (let's say) is designed such that if you drive it according to a particular drive cycle, 'cycle A', then you achieve 100% of the quoted range.
2) If 'you' drive that BEV according to the way 'you' want to, then it might not be according to 'cycle A'.
3) If (1) and (2), then 'you' might not achieve 100% of the quoted range.

Let's now swap a few of those words around;-
1) A BEV (let's say) is designed such that if you drive it according to a particular drive cycle, 'cycle B', then you achieve 100% of the required charging for the 12V battery.
2) If 'you' drive that BEV according to the way 'you' want to, then it might not be according to 'cycle B'.
3) If (1) and (2), then 'you' might not achieve 100% of the required charging for the 12V battery.

If you want to clarify which, of those lines, don't make sense, then let me know.
 

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Did you leave the car On on Park while this test was going on?
I cant get my OBD device to connect to the ECU when the car is off but turning the car on would put a load on the 12V no?
So how do i get to the point where i can make this graph in my car?
Use a BM-2 Battery Monitor. It draws only about 2 mA, won't disturb anything and logs data at 2 minute internals for a month.
You can't use the OBD data to monitor this because the car's systems need to be awake and will be maintaining the 12V system voltage to between 13 and 14.4 V from the traction battery.
 

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It makes perfect sense. So what you actually meant there was 'it doesn't make sense to me'.

I'll spell it out;-
1) A BEV (let's say) is designed such that if you drive it according to a particular drive cycle, 'cycle A', then you achieve 100% of the quoted range.
2) If 'you' drive that BEV according to the way 'you' want to, then it might not be according to 'cycle A'.
3) If (1) and (2), then 'you' might not achieve 100% of the quoted range.

Let's now swap a few of those words around;-
1) A BEV (let's say) is designed such that if you drive it according to a particular drive cycle, 'cycle B', then you achieve 100% of the required charging for the 12V battery.
2) If 'you' drive that BEV according to the way 'you' want to, then it might not be according to 'cycle B'.
3) If (1) and (2), then 'you' might not achieve 100% of the required charging for the 12V battery.

If you want to clarify which, of those lines, don't make sense, then let me know.
Where is the evidence that the way you drive the car affects the charging of the 12v battery? My battery monitor shows about 14.7v whenever I am driving the car. The BM2 also shows the 4hr charging cycle at 14.7v (not the 13v you stated previously). Moreover, if your theory about sulphating was correct then most if not all of these cars would have this problem, however, it seems that only a small percentage have 12v failures. It seems more likely that the cars with the failures either have individual faults or have had something left switched on. We know the 12v battery does not provide much power, hence the battery warning if you leave the car on but not ‘started’ - which is why Hyundai techs (the knowledgable ones) connect an external battery before working on the car. There has also been evidence posted previously that appears to show the car does not fully shut down if the boot is not fully shut or with some OBD devices - and such drain would significantly affect the battery.
 

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Do all the Kona Electrics have the same type of 12V battery? I wonder if some were supplied with AGM and others with lead-acid.
 

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Where is the evidence that the way you drive the car affects the charging of the 12v battery?
A significant minority of people have problems of this nature with BEVs, others don't.

It's the only logical conclusion. Once you eliminate everything that's not possible, and the thing left, however improbable, is the answer.

This is the evidence.

(edit; mistake 'maj' for 'min')
 

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A significant majority of people have problems of this nature with BEVs, others don't.

It's the only logical conclusion. Once you eliminate everything that's not possible, and the thing left, however improbable, is the answer.

This is the evidence.
No that is not true. Firstly there is no evidence that a significant majority of people have a problem with the 12v batteries. Sales of Kona EVs in UK number in the thousands and there does not appear to be that many with the failure. Of the forums and FB groups I see for the Kona there have been less than a 100. There is clearly a problem with some cars, or the way they are used but we have no evidence of the cause. If the cause was owing to a design failure it would be common to the vast majority of these cars, but this is clearly not the case so there must be another factor.
 

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No that is not true. Firstly there is no evidence that a significant majority of people have...
heh, sorry, I meant significant minority. Typing-out error. Edited above.

(Obviously, a majority is always significant.)

I never said there was a 'design failure', I said there was a mismatch between usage cycles and the charging algorithm.

If one used one's ICE for short trips in winter, one already knew the battey was going to suffer. This is a simple example of a mismatch between use and design regarding 12V. Same here now, but it's unclear how they have programmed the 12V charging.

Why not just leave it charging at 14.4V when on? Let me ask you that first? OK, so for some 'efficiency' purpose. Fine, that is right. Now, by how much?

Here we enter the piece of string length argument. At some point it can be cut too short for 'some' but long enough for others.
 

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If one used one's ICE for short trips in winter, one already knew the battey was going to suffer. This is a simple example of a mismatch between use and design regarding 12V. Same here now, but it's unclear how they have programmed the 12V charging.
Why not just leave it charging at 14.4V when on? Let me ask you that first? OK, so for some 'efficiency' purpose. Fine, that is right. Now, by how much?
True re the ICE. But, I mostly only ever use my EV for short trips (average less than 15 miles each way) and it is fine so far (touching wood now…)

The car does keep the battery at about 14.7 volts when being driven. I noticed it once drop down to nearer 13.5v on a very rare long journey.
 

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If the original question has been left answered: (Kia) manual states that interior lights go off after 20minutes, with an exception of tailgate: tailgate light stays on as long as the tailgate is open. I hope they would correct this. Sounds unnecessary and quite stupid IMO.
Obviously it will drain the battery empty sooner or later, and the 12V battery is relatively small.

If you have UVO or bluelink it does send you a notification if doors/tailgate/bonnet is left open. Better allow notifications!
 

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True re the ICE. But, I mostly only ever use my EV for short trips (average less than 15 miles each way) and it is fine so far (touching wood now…)

The car does keep the battery at about 14.7 volts when being driven. I noticed it once drop down to nearer 13.5v on a very rare long journey.
The well proven charging regime for a 12v Lead acid battery consists of 3 stages:
1) Bulk - the battery is fed with as much current it wants until this drops to a under 1 amp. (depending on what current is available from the charger)
2) Absorption - the voltage is held at 14.4v or 14.7 for AGM for final trickle charging to 100%
3) Float - the battery is maintained at 13.6v indefinitely.

The charger will cease charging periodically so it can assess the actual battery state based on the voltage after a 10-15minute pause otherwise it would not be able to determine when 100% had been achieved. Otherwise it would cause excessive gassing.

So it is perfectly normal for the voltage to drop to around 13.5v on a long drive - it just shows that it has been fully charged and is now being maintained.
 

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The well proven charging regime for a 12v Lead acid battery consists of 3 stages:
1) Bulk - the battery is fed with as much current it wants until this drops to a under 1 amp. (depending on what current is available from the charger)
2) Absorption - the voltage is held at 14.4v or 14.7 for AGM for final trickle charging to 100%
3) Float - the battery is maintained at 13.6v indefinitely.

The charger will cease charging periodically so it can assess the actual battery state based on the voltage after a 10-15minute pause otherwise it would not be able to determine when 100% had been achieved. Otherwise it would cause excessive gassing.

So it is perfectly normal for the voltage to drop to around 13.5v on a long drive - it just shows that it has been fully charged and is now being maintained.
Aye, what you quote is for standby service.
 

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Meanwhile, ADAC posted statistics regarding EV failures.
The winner is.... 12v battery with 54% of all faults. Then come all other electrics, tyres, others...

(down the page)
 

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Meanwhile, ADAC posted statistics regarding EV failures.
The winner is.... 12v battery with 54% of all faults. Then come all other electrics, tyres, others...

(down the page)
This can only mean the car's charger is not doing what it should, probably compounded by excessive drain while powered down.
I'd be tempted to fit a larger battery but this won't help if the charging is inadequate.
 

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Here's a quick graph pulled from OBD data I logged in March 2021 showing how my Kona (with update 196) treats the battery while driving. Each sample of 12V system voltage is at a 5 second interval and the drive is somewhere in the 2 hour range. There's a linear trendline added. The 12V battery is exposed to that system voltage (via the IBS current sensor on the negative terminal) and will take on current as its own state of charge allows. It's not accurate to assume that the current draw by the battery is linear with voltage but it gives an idea of what the battery is exposed to.

The bottom line is that the average system voltage during this drive is not all that high compared with scheduled aux battery charging, traction battery charging or utility mode, where it's a constant 14.6 - 14.7 V for 20-30 minutes or the full duration in the case of utility mode.
I have noticed on other drives that when more 12V accessories are running the average voltage tends to run higher.

144211
 
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