Mine is currently at the dealer as 12v battery failed. Dealer installed new battery and then found that the car was draining it when off. Still being investigated and I have a Thrifty replacement car. My ICCU failed in Dec and was replaced.

 

Please update us when/if they tell you what the actual problem was.

 

One of the first software updates to my P45 was to stop the excessive polling of the charge flap (IIRC). Everything has been fine since.

Also, I have heard that the (pre-ICCU update) firmware stopped topping up the 12V if the main battery was under 20% which seems completely bonkers. Having never left the car in that state for long, I haven’t been lucky enough to prove this.

The car keeps warning me that accessories are draining the 12V because I have a dashcam running. Again, this is pretty poor show as the car should just top up more frequently.

 

Again, this is pretty poor show as the car should just top up more frequently.

The car does top up the 12v frequently. However, if it has to do this too often it stops so as to prevent further issues as it considers they may be a defect.

 

We have all seen the posts about 12v battery failures, but we seem no further forward with the actual cause. Hyundai seem mute about it and whenever I see a post it seems there is no definitive stated cause. In fact many times I see reference to a new 12v battery being fitted but no information as to if the old battery was actually load tested or any information is the tech involved even looked at the other battery data that they can apparently see.

What we know about this issue so far seems to be that if the 12v battery fails there are 3 possible causes

a. Either the battery is defective (so get a new 12v battery)
b. or it is not being correctly maintained by the car and hence topped up from the HV battery. There has been at least 1 report of a 12v battery sensor failing that meant the battery was not being correctly maintained.
c. or it has been loaded more than normal.

For this reason, I have had a BM2 battery monitor connected to my I5 12v battery since purchase and it was on my Kona for 4 years before that. A BM2 or the service tech using Hyundai kit should be able to see what is and has been happening to the battery and therefore see if it is being charged as expected. Similarly, a BM2 or the Hyundai tech will be able to see if there is unexpected loading. Excessive loading could be caused by such things as not leaving the car in the On or Utility mode when using other electronics or overuse of high-power items like the tailgate or excessive polling of Bluelink. In addition, excessive loading could be caused by a defect. In the past charge port failures and ICCU failures have been identified causes.However, I have seen no reference to any such data by people who have had a 12v fail.

Plenty of posts about 12v failures but no reports of actual causes. Some have had the 12v replaced but again no clear report about any load testing of the old battery or info from Hyundai about what info they could see.

So has your BM2 given you any info about what it going on ?

 

Never had a problem so my BM2 traces look normal Their are many others that show an excess load before failure.

 

The fundamental issues seem to be:

• The "recharge the 12V using the HV and ICCU" only runs for ~10 attempts. This seems to be an over-reaction to the risk that a high 12V drain might eventually drain the HV.
• Rather high 12V drain from each connection to the car by remote services due to pulling it out of deep sleep (which is exacerbated by either "helicopter" owners checking in frequently, or by services such as IOG which used to poll the car API over-frequently)
• Possibly some timing/race-condition bug where if something happens just as the 12V recharging is happening (e.g. starting an HV charge) the ICCU gets in a confused state and doesn't subsequently attempt to recharge the 12V.

 

I agree in part with what you say. However, my Hyundai Kona was fine for 4 years (and there were plenty of 12v failure posts on that forum!) and my I5 has been fine do far after 2 years.

• Therefore, there should not be anything that loads the 12v such that it needs toping up more than 10 times.
• There should not be any need to regularly poll the car using Bluelink.
• Unfortunately, no data on this.

The key point is despite a number of these failure we still have no data on the real cause(s) besides some specific failures such as ICCU/Charge Port/ 12v battery itself.

I have not seen a single post from anyone that has had the 12v fail with a clear diagnosis of the cause other than the battery failing itself and being replaced - which may simply be a temporary fix if there was an underlying fault.

 

That's a very sensible list of ideas and any could be true. Is there a way of finding out what may be going on ? I'm guessing the manufacturers know/ could find out if they wanted/ needed to ??

Or is this just a problem for owners or if warranty do not their problem?

 

The issue is that cars now have lots of draw (not high) coming from electronics. All these remote control services etc all use a lot of power. Our last ICE car (volvo) had a lot of the same features and low and behold, I had to replace the two 12V batteries in that car (main battery plus a support battery).

The general view is that we need to probably move to 48V which will be a lot more reliable. The Cybertruck is the first car doing this, and I expect the rest of the industry will follow. It's a bit like HMG/Kia with 800V.

Higher voltages make a lot of sense.

 

But what/ who would give the definitive reason for a 12v failure ?? There is no readout from the car with a reason and either the battery is replaced by the owner or the dealer, with likely no investigation ? "It's just the 12v" it gets replaced.

So I'm guessing, like the OP, that owners using a BM2 or similar is the only way "we" are going to find out ??

 

But what/ who would give the definitive reason for a 12v failure ?? There is no readout from the car with a reason and either the battery is replaced by the owner or the dealer, with likely no investigation ? "It's just the 12v" it gets replaced.

So I'm guessing, like the OP, that owners using a BM2 or similar is the only way "we" are going to find out ??

Hyundai tech has the ability to see everything the BM2 records plus other info. The problem is that the techs first response seems to be to change the battery without looking for a deeper cause. Anyone with a 12v failure needs to push the techs for more analysis and data. More info in tis and other posts on this forum - https://www.ioniqforum.com/threads/12v-battery-troubles.48522/page-4#post-594779

 

In my opinion, there could be another lead acid battery issue at play here.
Battery sulphation is not easy to spot, until the failure point. Effectively the battery voltage when open circuit or charging appears normal on a BM2 or a voltmeter . The sulphation crystals accumulate to coat the plates, reducing the effective plate area and the associated battery capacity. So the battery might appear fully charged on a BM2, without any unwanted discharge occurring, but the effective capacity could be much lower than when new.

The smart charger repair modes attempt to overcome this by applying a pulsing voltage to the battery of higher voltage than normal charging. The higher voltage can break through the sulphate layer and to some extent reverse its formation.

According to the web wisdom the sulphation can occur owing to undercharging and having the battery in the undercharged state for long periods. But also can apparently be caused by overcharging.
The regular use of a smart charger repair mode might be a good way of extending the battery life.

 

In my opinion, there could be another lead acid battery issue at play here.
Battery sulphation is not easy to spot, until the failure point. Effectively the battery voltage when open circuit or charging appears normal on a BM2 or a voltmeter . The sulphation crystals accumulate to coat the plates, reducing the effective plate area and the associated battery capacity. So the battery might appear fully charged on a BM2, without any unwanted discharge occurring, but the effective capacity could be much lower than when new.

The smart charger repair modes attempt to overcome this by applying a pulsing voltage to the battery of higher voltage than normal charging. The higher voltage can break through the sulphate layer and to some extent reverse its formation.

According to the web wisdom the sulphation can occur owing to undercharging and having the battery in the undercharged state for long periods. But also can apparently be caused by overcharging.
The regular use of a smart charger repair mode might be a good way of extending the battery life.

Maybe, but if this was the case there must be an underlying issue that causes it. As 12v failures are a minority this would indicate it to be a fault rather than a design issue.

 

When the car is charging the 12v battery, is it at a high enough voltage for long enough? Getting on for 15v. And I wonder what current? BM2 will answer the former, a shunt will be required for the latter.
Lead acid needs a decent long charge to fill properly.

 

When the car is charging the 12v battery, is it at a high enough voltage for long enough? Getting on for 15v. And I wonder what current? BM2 will answer the former, a shunt will be required for the latter.
Lead acid needs a decent long charge to fill properly.

Does seem to be plenty high enough for most cars as it is only a minority that have the failure.

 

I have suffered about this. In an ICE with the alternator doing constantly the 12v is getting this long slow charge at around 14v

Whereas an EV HV battery will anybody freely only charge the 12v for occasional short periods ?? It's this the problem (see sulphation from @davesul ?)

 

Unlikely as the ICCU monitors both voltage and SOC to calculate the charging cycle.

 

Not all owners will have an issue. For example, if you use the car every couple of days (or more often) for a decent length run then even with fairly high drain (lots of API wakeups, dashcam in parking mode) the 10 recharg cycles the car gives the 12V are enough to keep it just about topped up.

But if you use it less often, even just once (e.g. while it is parked for a week at the airport) then it can drain all the way. And while the limit on the number of 12V charge cycles means you won’t come back to a flat HV battery, you may well find a flat 12V, which is just as annoying unless you are prepared and keep a charged booster in the frunk.

Also once a 12V battery has been drained once it may be damaged, meaning it discharges faster in future.

The manufacturers could address this e.g. by using a deep-cycle battery which is more resistant to such treatments (or a lithium battery, possibly) # which would increase BoM/parts costs of course. And/or they could programme the ICCU to do a better job of maintaining the 12V SoC and recovering its SoH after a discharge episode. And/or they could programme the car to better handle intermittent waking from sleep when responding to API calls.

See e.g. @donald’s suggestions in https://www.speakev.com/threads/12v-batteries-in-evs-wrong-type.19920/post-352411, https://www.speakev.com/threads/how...ly-work-and-why-bev-users-should-have-any-concerns-about-it.167208/post-3191747 and https://www.speakev.com/threads/12v-saga-continues-maybe-even-more-than-that.164680/post-3136854 for discussion on the 12V battery type and maintenance points.

 

E-GMP cars charge the 12V at 14.7V or so.

However, sometimes they seem to put it on a sustaining charge of around 13V (typically I've seen this towards the end of a long overnight AC charging session).

The only times I've had an issue with the 12V seem to have correlated with higher-than -normal drain plus leaving undriven for several days.

I ascribed the higher drain to API calls from Octopus (Kia API integration), but didn't get to the bottom of it before I switched to Zappi integration - since which we haven't had 12V issues.

(See the sharp drops on the LHS of the plot, which was during the IOG charging window - after the charging window ended the drain was much more reasonable.)

 

View attachment 187624

I ascribed the higher drain to API calls from Octopus (Kia API integration), but didn't get to the bottom of it before I switched to Zappi integration - since which we haven't had 12V issues.

(See the sharp drops on the LHS of the plot, which was during the IOG charging window - after the charging window ended the drain was much more reasonable.)

This graph shows clearly what damage the Intelligent Octopus does to the 12v battery.

13V is the floating voltage, applied once the 12V battery is considered fully charged (between 92-100% SOC) by the ICCU, so it is only maintaned but not charged anymore.

 

Note that IOG didn't always result in such steep drops on the 12V. Mostly it would look more like:

But sometimes it seemed to get stuck in an API death spiral - my hypothesis was that either IOG or Kia API was getting stuck in a loop and just making calls to the car over and over.

Others have also reported that sometimes it seems the ICCU can get wedged so that it no longer charges the 12V - and doesn't start again even after the car has been driven (which is meant to reset the max 10 attempts count). I haven't experienced that, though.

 

I haven't experienced that, though.

ugh delayed jinx has struck!

Left car to charge last night (70% to 90%) in the overnight IOG window (Zappi integration). This morning found the car with flat 12V. After jump starting saw that the traction battery was still at 70%, and the BM6 data shows that when I plugged the car in (6pm ish) the 12V voltage was already a bit low (11.9v) and the dropped at a steady rate for a couple of hours to about 11.6v. But then at around 8pm it started dropping to 9.75v by 9pm, then struggling on until 11.25 ish when it died completely.

The car had last been driven (albeit briefly) at around 8am the previous day so it shouldn’t have got to the “sacrifice 12V to preserve HV“ stage. Normally the ICCU would recharge the 12V when it gets down to somewhere between 12.35v annd 12v, and would then hold it at 14.8v or so for 30-120mins to recharge it. That didn’t happen this time.

Possibly I was unlucky and triggered a bug I’ve seen mentioned before, where starting a charge can cause the ICCU to get wedged somehow? The dealer told me they’d applied the ICCU update last time it went in, but not sure how to check.

Left car for several hours today in utility mode to ensure it had at good chance to recharge the 12V. It ran at 14.8v for just over an hour, then sat at 13.35v for about 9hrs, then went back up to 14.2v for an hour or so.

Will be monitoring over next few days and likely then will take it in to dealer again.

 

Breaking news of a worldwide recall for all E-GMP cars regarding the ongoing ICCU issues so we might get a resolution to this kind of problem soon.

Hyundai, Kia to Make Largest EV Recall since Launch of First EV Models

Hyundai Motor Group will launch a large-scale electric vehicle recall. It is the largest voluntary recall in three years since the automaker entered the market

www.businesskorea.co.kr

 

That has been the update for our cars for months. You can see it for your car on https://www.hyundai.de/service-zube...ktionen/?fbclid=IwAR0AT1zwWmBhK0GH8ECrwTVj6nlVMkW28D6KlcMC_48B4SXLr3J5hbs3gY0#/

 

I personally doubt this will change soon.

The short answer is that we need to all move to 48V technology. Cars no longer have high drain devices and little onward power draw requirements. We now have less peak demand but more general draw requirements, and also a need for contact/draw when car is off. This will require a change of technology which we are starting to see. The problem is that all components of a car have been developed for 12V and that will need to change. We will also need to move to something by like LFP to support general components.

 

[]

 

The ICE Volvo had support batteries ?? More than one 12v ?

 

Yes - it has two batteries.

I think one was to run the Infotainment, and the other to start the car. Don't quote me on their full purpose, but there was definitely two. I suspect that has changed for the EV models, but current ICE has two.

 

12V battery failure seems to plague every EV and some PHEVs that don't use the 12V battery for starting the engine. I first encountered it with the 2013 Prius PHEV I bought new. I had the 12V battery fail after two years. Had another one fitted under warranty and that failed two years later. The third 12V battery was on its last legs when I traded the car in 18 months after that. The I Pace I have now had the small 12V battery fail after just over 3 years, so I replaced both of them. The I Pace owner's forum was full of tales of 12V batteries failing at around the 3 year mark. Seems to be something to do with the way that the 12V battery is run in a lot of EVs, as the problem seems to be across several different makes, the only common factor is that these batteries are never required to provide a high current to start an engine.

I've wondered if this is the key, that these 12V batteries never get hammered every time the car starts. I remember reading somewhere that Tesla were looking at switching away from using a lead acid 12V battery and fitting a small lithium one instead. Much as I think Musk, and Tesla, are a bit of a shambles I can't help wondering if this may be important. Lithium batteries have a very much better tolerance to being lightly discharged and charged than lead acid batteries, and perform well when they are given a gentle life. Could be that the gentle life lead acid batteries have when used in an EV is the reason they fail prematurely, perhaps.

 

We desperately need to move to a higher voltage lower amps architecture (48V). I don't want to bring up the Tesla CT specifically as it is a pile or garbage, but the higher 'low voltage architecture' of 48V showcased in this vehicle is still where we need to all be headed towards. That will go some way to helping sort the problem.

 

About a year ago VW replaced the 12v battery on my ID3, which was then two and a half years old, with a different one as a recall. There had been no problem with the original battery.

Since it's pretty well hidden by plastic covers, I can't see any labels. Exactly the same size as the first one but supposedly different in some way.

Looks like some manufacturers have reacted to the changed needs of a 12v battery for an EV.

 

It does surprise me that an EV that is merely parked can consume enough power from a 12V battery to require multiple recharges a day. Thinking back to some of the cars I had in the 1990s which were effectively sitting there with volumetric alarm and remote central locking active for weeks between drives. How did they cope? Are today’s alarm and central locking systems so much more inefficient?

 

Bottom line is that, for some reason, designers seem to have stopped caring about standby power consumption. Same is true for phones. 20 years ago I had a Nokia that would last around 3 or 4 weeks turned on, without making calls. Now you're lucky to be able to find a phone that lasts more than a day and half on standby.

 

@Jeremy Harris (specifically), I think I know the sort of tech minded person you are and might appreciate this thread I created, I don't think you were active at the time so just highlighting it.

People think the 12V lead acid battery is simple, and can be abused and ignored. The truth is that even today the way it works is not fully understood;-

https://www.speakev.com/threads/lea...-acid-battery-chemistry-well-understood-chemical-reactions-or-a-dilemma.128658/

 

The 12V bus can be a considerable chunk of the battery depletion in some situations.

Imagine trundling through city traffic for a week. Your commute is 10 miles and takes an hour. That is reality for some people.

BEVs are great in this sort of situation (from an energy/environmental perspective, at least). 100 miles a week, at 6mi/kWh is 16kWh. In 10 hours.

1.6kW traction power.

Your 12V bus probably consumes 500 to 800W.

So, running the 12V bus could be up to a third of the total energy that the high voltage battery delivers.

 

Just to be clear - you are saying that an EV shouldn’t keep the 12V topped up as an ICE would when the engine is running?

 

My MG ZS was left for 3 months without use and the battery was drained on return such that the key failed to unlock the car electrically. Now 3 months might be seen as an overly extended period for not charging and the voltage was clearly down. I didn't put a meter on the battery but did put a charger on it that is supposed to bring the battery back to good. A CTEK .8 amp charger which showed the battery at its lowest where charge is added in pulses. It didn't take long to progress to the next stage where it builds the charge and that is where it remained for days. I swapped that charger out for a 5 amp Aldi charger which is supposed to work in a similar way. That was showing a voltage of about 12.8 as it charged and it took days to move up to 13.2 volts. Clearly the battery is not at its best and I am regularly putting the charger on to see if I can bring it back up to normal. The CTEK has never advanced above its 3 stage where it is supposed to be working up to the full voltage. I did notice after a long run that the battery was being held at the stage 3 of 6 on the CTEK charger so I am guessing that the voltage put into the battery is never as high as an alternator would. I ran an Astra for 17 years on its original battery using the CTEK charger to bring it back to life after that car wasn't used much after I retired. I will persevere with the battery chargers to see if the battery can be mended, the car at 4.5 years old is due for a swap so I am reluctant to spend out on a new battery. I just have to persuade Mrs G to agree to shell out a few thousand for the next car. The MG has suited us well so I would quite likely replace it with a newer one with the LiFPo battery 51 kW with a pano roof!

 

If you have a sulphated battery, the way to desulphate quickly is by a series of high voltage pulses, which causes hydrogen evolution (in solution) and coverts the hardened sulphate back in to being sulphuric acid. This has to be pulsed, else the hydrogen will come out of solution and you will get outgassing.

A regular charger can't usually do this.

A good desulpation charger can do this and mostly sort out a significantly sulphated battery within a weekend, but it will not be perfect, there will still be sulphation left. Repeat every weekend for a month, then do it every couple of months.

After such a cycle (or in place of doing it at all), the other way is to put on a >14V <1A trickle charge for a few weeks, continuously. This creates the electrochemical environment for the slow solvation of the sulphate back into the acid but it is a very slow process.

 

Yes, I think just regular but frequent charging should also bring it back into full 'bloom'.

If you know your car is going to be unused for a few days, put the battery charger on it if you can. You may not need to disconnect your leads, BUT CHECK what the charger says, some provide a clear statement that it can be used on batteries 'in a circuit'. It's common for chargers to recreational vehicle battery systems.

You need to take your own advice on what steps to take to connect your particular charger to your particular battery. I would recommend AVOIDING using a desulphation cycle on a battery still connected to the car, though, as the voltage pulses can make some circuits 'unhappy' and throw an error.

 

The argument of lighter wiring is definitely still there.

But greatly weakened, because the savings in copper from thinner cables might be more like 200 grams than 2 kilograms for a typical EV.

Also systems many key systems like HVAC don't run on the HV battery (yet) - most EVs still use the 12V systems to power systems such as HVAC contrary to what you have stated.

Name any EV which runs its heating or cooling power from 12V. Even a humble LEAF has a high-voltage heater and air-con compressor. Most do use 12V for the ventilation fan, which typically draws about 100 watts (around 300 W at maximum speed), often only a short distance from the DC-DC converter so not needing a long power cable.