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Kia Soul EV 2020
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Being an engineering manager myself I had the same question :)

I must get this OBD2 dongle someday. Although I don´t wanna. It´s a car, not a hobby project
Things are even worse, as my OBD2 doesn't seem to work with Kia. Used to with Golf GTE MY15...
 

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Not really sure what this thread is about anymore, but earlier a fair discussion on the 12v battery, so check the manual on the "battery saver" or similar, where the car will automatically recharge the 12v battery from the main traction battery if it gets low. I suppose long times between charges and running.

That should eliminate the 12v battery going low if there is not a fault in the electrical system.
 

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Kia e-Niro MY20 64 kWh - Gravity Blue
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Discussion Starter #23
I think most owners are aware of the auxiliary battery option. However, there's numerous people that find their 12v battery has gone flat in spite of this option being activated. We're all apprehensive about this happening.
 

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Not all of us are apprenhensive ha! This is my 3rd EV and have never had the 12v battery go bad. (yes I know it happens)

With no mention of this (battery saver function) in the thread, and so many people posting questions about things clearly in the manual, I feel it was appropriate to mention this.

Greg
 

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From what I can tell and have read on this subject, it's clear that while in theory the e-niro will keep the 12v battery charged up, in reality the functionality doesn't always deliver the intended outcome and some drivers have been left with an unexpected flat 12v battery. There have been a number of youtube videos on the subject. It's also clear that this flaw is not unique to the kia e-niro, and is an issue for many electric vehicles. A search for "12v battery issue in electric cars" identifies drivers on this and other forums who have experienced flat batteries.

If you don't want to be in the position of a flat 12v battery, then the preventative measure seems to be regular, for example monthly, charging of the 12v battery charger with a smart battery charger. These are readily available on Amazon and elsewhere for around £20 to £30.

However, i think most people don't take this measure and are still basically fine for the vast majority of time - if the issue was so widespread and common, there would be a lot more noise on this forum for example if people were regularly trying to start their cars and failing due to a flat 12v battery. I think it's plausible to conclude that the self charging functionality within the e-niro when the e-niro is plugged in to a charge does generally work, although in some circumstances it fails to deliver sufficient effect.

I suppose what you do about it depends on your own appetite for having an unexpected flat 12v. If you really don't have any appetite for that, regularly charging the 12v with a stand alone charger is the way ahead.
 

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I agree, my opinion would be to not do anything unless the problem occurs.

If it does occur, unless the battery has actually gone defective, I would be all over the dealership to fix it, since in the main it works.

I'd only invest in a dedicated charger and a regular charging schedule if this was a systemic and very prevalent flaw, which it clearly is not.

Greg
 

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MY2020 Kia e-Niro 4 ordered 1 Sept, due whenever EST approve my Scottish Government EV loan...
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Presumably one can measure the voltage of the battery using a multimeter to determine if any intervention is required? This seems simple and low cost and avoids shelling out for any OBD2 gear for those that just want to avoid the 12V battery plague.
 

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A comment on the posts that suggest the 12v battery gets a charge when the drive battery is being charged.

If this were so why doesn’t the main battery just keep the 12v battery fully charged regardless of whether it’s being charged or or not, it has loads of capacity?

This doesn’t explain why the 12v battery might only get charged when running the car unless the regen energy is firstly used to charge the 12v battery in the first instance.

That seems to make some sense to me.
 

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I think all of this is in the manual. I do know that the charging of the 12v battery when the traction battery is NOT being charged is controlled by the feature I mentioned.

So again, if you charge the car regularly, the 12v should never go down. But if you left it a long time in an airport parking lot, the 12v will lose charge much more quickly... lead acid batteries have a much higher self-discharge rate than lithium ion.
 

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E-Niro 64kWh '4' since 22/9/20 (was Prius)
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Presumably one can measure the voltage of the battery using a multimeter to determine if any intervention is required? This seems simple and low cost and avoids shelling out for any OBD2 gear for those that just want to avoid the 12V battery plague.
If you want to monitor the 12V battery state, you can’t beat one of these things. It logs continuously the Voltage over the last 30 days. You connect your phone/tablet app via Bluetooth LE whenever you want to view the data. The app displays Voltage graphs and you can select any day to view the 24h graph. It only draws 1mA from the battery (negligible, has no effect on anything). Fantastic device. When I get my car (later this week hopefully) one of the first things will be to add this device across the 12V battery terminals! Then I’ll see WTF is going on with it. Highly recommended!

Peter
 

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For what it's worth the presumably-similar Kona EV charges the 12V battery for 30 minutes at the start of the first drive of the day. (By "charge" I mean the battery is subjected to a constant voltage of 14.65 V for that interval, so a damaged or degraded battery may not accept as much energy, explaining why many who have a dead battery see addition occurrences.)

For the remainder of time driving (even after rest stops) the system voltage dithers between that and 13.0 V, in my tests averaging 13.6 V. The net current into the battery during that time is approximately zero, where I think the intention is to not draw on it since there is clearly no need to. I don't know how long you would have to drive before another 30 min charge event occurs.

When charging (certainly on AC and likely DC) the same program applies but after the 30 min charge period the voltage settles to 13.0 V, again appearing to avoid any discharge for the remainder of the time charging.

When left parked, the program depends on whether the latest BMS update has been applied. On the old software (which I have) the aux battery is charged (assuming the Aux Battery Saver option is "on") for 20 minutes after the first 24 hours left undisturbed. Subsequent events are every 24 hours + 20 minutes, i.e. exactly 24 hours after the conclusion of the prior event.

Subsequent charging or driving under 30 min seems to not affect the battery saver schedule. However if 30 min is exceeded then the schedule is reset to coincide with the end of that usage, presumably because the aux battery has experienced a "full" charge event.

The BMS update seems to reduce the timing to every 4 hours for the first few days, then revert to daily only. In both software versions there have been oddities noted; for example a 30 minute battery saver period instead of 20 minutes, or waking up on schedule but then failing to charge. As noted, the BM2 monitor is a good way to characterise the behaviour without disturbing the voltage by even opening a door.

It's not clear how the aux battery's condition is assessed but most likely this is the responsibility of the IBS (intelligent battery sensor) on the negative terminal, possibly using coulomb counting as is done for the traction battery. Voltage alone would not tell the whole story and that may explain the occasional weirdness in the schedule where all I have to go on is voltage from the BM2. It's unclear if the IBS is active at all times, diligently logging any drains, or only when the car has woken up.

Personally I've had no problem with the aux battery and it stays between 12.6 and 13.0 V while sitting, depending on the elapsed time since the last charge. But I don't have the app or any connectivity while parked.

Charge voltage is no-doubt temperature compensated so colder regions may see a higher charge voltage than 14.7.

Note that Utility mode keeps the battery at the charging voltage level for the duration left in that mode. Also, if you externally draw power off the battery it makes sense to use the chassis ground as opposed to the battery negative terminal so that the IBS sees that current.

Last note, other than leaving the hatch ajar or similar, the only other noted battery drain appears to have been caused by using the app via an Android emulator.
 

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Kia e-Niro MY20 64 kWh - Gravity Blue
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Discussion Starter #32
@KiwiME that is by far the most informarive post I have seen on the subject. Kudos. I'l start looking for which version in the e-Niro presumably has the latest update and see if it matches mine.
 

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I certainly agree @Xinix , @KiwiME 's post is excellent.

@KiwiME - so to summarise your view on the causes of occasional flat 12v batteries is either due to :

a) an already degraded 12v battery where the 30 minute charge is inadequate due to the degraded status of the battery; or

b) the software issue that causes the system to "wake" up but not deliver the actual charge to the 12v
 

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E-Niro 64kWh '4' since 22/9/20 (was Prius)
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@KiwiME Yes I agree, that is a very informative post thanks. It also explains the reports that a depleted SOC battery never really recovers itself properly but once a good charge from a mains charger has been done, things seem to usually remain ok thereafter.

Though I can’t for the life of me see why they took such a strange approach to managing the 12V battery. It completely explains why the car can not recover itself very well from a depleted battery condition (Such as the long transit on a ship, maybe even with a jumpstart to get it going). Charging Voltage of ~14.7 will put plenty of current into the battery (when it needs it) but 30 minutes is nowhere near enough if the battery is depleted! It appears that thereafter, it just breaks even with the various 12V loads present. Could it be that if the battery is heavily depleted in SOC, the 30 minute period is extended? That would make some sense if so.

Why didn’t they simply apply a constant Voltage charging at ~13.8 - 14.2V at all times when the car is operating or plugged in. That would take care of all conditions. The battery would just draw current if it needed it and not if it didn’t. It could be temperature compensated within that range for winter summer variations. That is what Prius does and effectively what most conventional alternator equipped ICE cars do (prior to recent Smart alternators which are equally as whacky but that’s quite another story).
There must be some reason why they did it this crazy way, but I can’t see it. Obviously they are a world class manufacturer and can’t be stupid or lacking in engineering talent. Very bizarre IMHO.

Peter
 

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Prawlin:

At a constant voltage of 13.8 to 14.2 you could eventually start overcharging the battery, that's why smart chargers shut off. And clearly daily charging will eventually recharge the battery.

All of this assumes there is not some constant drain on the battery that exceeds the charging current on average.

The days of "trickle charging forever" were gone many years ago, even for non lithium ion batteries.

Greg (a non-retired electronics engineer ;))
 

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For some time now I have been looking at the concept of a Lithium Battery drop in replacement and whilst simple in theory is proving remarkably slippery when trying to get someone to agree that their drop in battery would work. Of course its much easier, and far better understood when its an ICE car with a alternator that runs all the time. These BEV's are far more complex in their charging regime (see post a few above this one by KiwiMe)
On the plus side - charges faster (would take more charge in the limited charge duration)
More Reliable than lead, lasts longer. More tolerant of abuse, and decent ones contain BMS hardware to prevent abuse.
Can go almost flat with no damage (see above comment about BMS)
Reassuringly expensive (OK - so maybe this should be on the Con side)
Lighter, Smaller

Whats not to love
 

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The problem is the charging voltage/current.... the system is set up for a lead acid battery. You would basically need a separate charging circuit to protect the battery.

If you solved that, then you are left with what the car "thinks" the battery is doing, and that you cannot change easily, you would have to "fool" the car by presenting an expected response, i.e. voltage in response to charging attempts and just simple battery voltage level.

Technically it could be solved, practically no way, just too much "fooling" of the car's electronics.

Greg

p.s. "Can go almost flat with no damage " is NEVER true about a lithium battery, with the right circuitry it will disconnect, but actually going flat is death to a li-ion
 

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E-Niro 64kWh '4' since 22/9/20 (was Prius)
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So would a possible fix be to leave the car in "utility mode" for a few hours when it's first received to ensure the 12V battery is at maximum charge?
An interesting suggestion. If the utility mode really does hold the battery up at ~14.7V constantly, that could certainly be an option worth looking at as it could possibly save the need for ever using an external mains charger. That could be an elegant workaround solution indeed.

I don’t have my ENiro yet so I can’t verify anything. Whilst it’s being charged, if you listen carefully to the 12V battery, when it reaches 100% SOC it will be gassing quite freely (if maintained constantly at that charging Voltage). So you could probably use that 'bubble and squeak' sound as an empirical indicator of reaching 100% SOC. A battery with a low SOC will never be gassing significantly (Unless the battery is defective/worn out).

Nice one.
Peter
 

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... a depleted SOC battery never really recovers itself properly but once a good charge from a mains charger has been done, things seem to usually remain ok thereafter.
... it completely explains why the car can not recover itself very well from a depleted battery condition ... Could it be that if the battery is heavily depleted in SOC, the 30 minute period is extended? That would make some sense if so.
Why didn’t they simply apply a constant Voltage charging at ~13.8 - 14.2V at all times when the car is operating or plugged in. That would take care of all conditions. The battery would just draw current if it needed it and not if it didn’t. It could be temperature compensated within that range for winter summer variations. That is what Prius does and effectively what most conventional alternator equipped ICE cars do ...
There must be some reason why they did it this crazy way, but I can’t see it. Obviously they are a world class manufacturer and can’t be stupid or lacking in engineering talent. Very bizarre IMHO.
Right, well first thanks to those who made 'positive' comments, that's always encouraging.
My understanding from reading about modern calcium lead-acid batteries is that charging is less simple than applying 13.8 V forever. It seem to be more complex and indications are that a higher voltage is preferred. That might coincide with smarter charging regimes that we see in ICE cars as well. It also seems that a depleted calcium battery takes a greater punch to restore, something the car may be incapable of providing.
So would a possible fix be to leave the car in "utility mode" for a few hours when it's first received to ensure the 12V battery is at maximum charge?
Yes, absolutely. And perhaps even as an alternative to an external charger from the auto parts store.
At a constant voltage of 13.8 to 14.2 you could eventually start overcharging the battery, that's why smart chargers shut off. And clearly daily charging will eventually recharge the battery.
All of this assumes there is not some constant drain on the battery that exceeds the charging current on average.
The days of "trickle charging forever" were gone many years ago, even for non lithium ion batteries.
Greg (a non-retired electronics engineer ;))
There was concern among Kona owners about overcharging, myself included, who are more familiar with 13.8 V systems. But, 14.7 V is how it works on the Kona so I can only assume that technology (i.e. calcium) has moved on and I have yet to catch up. I also have to assume that they designed the system to meet the charging requirements specified by Rocket.

In general, to comments regarding "why did they do it this way", I think perhaps electrical engineers may better appreciate the catch-22 involved (I'm an ME but am partial to the subject). The condition of the aux battery is not apparent without waking up a significant portion of the system. This is what the ABS (aux battery saver) does when initiated by its timer. And almost without fail it will find the SoC lacking and initiate a charge event which requires the LDC to activate and provide 14.7 V as a constant-voltage supply up to perhaps 100 amps. To do that requires that the traction battery main contactor be engaged. It is a matter of compromise between how often do you check the aux battery condition as opposed to unnecessary drain on the aux battery just to check it. When the aux battery is fully charged, the inbound charging current is small, under 1 amp, yet you have the overhead draw off the traction battery to contend with for the duration of the charge event.
The "BMS" software update reduced the period from 24 to 4 hours, then 24 hours after 2-3 days, pretty good evidence that this was the only easily applied (e.g. software) "fix" to counter unexpected depletion in field conditions.
Clearly an alternative would be to have a low-power charging system comprised of a small contactor and small LDC to provide a lower current more frequently, or even permanently. But the entire point of having an aux battery is to bootstrap the system into life. We all know cost matters in design and a conventional automotive lead-acid battery is a really cheap and conservative way to meet the requirements.

Here are some notes to clarify how I think it works and support what I've suggested, based on the wiring schematics and measurements.
The relevant "modes" of operation:
1. The system is asleep with quiescent drain on the aux battery, I think around 24 mA. There may be short bursts of current relevant to the app communicating which you can see as noise using the BM2 logging monitor. I don't think the system can evaluate the condition of the aux battery in this mode even if the IBS (on the negative terminal) is logging net coulombs 24/7.
2. The system is awakened by the charge timer, plugging in a charge cable, aux battery saver function (ABS) or start button (specifically without brake pedal), perhaps requiring up to 10 amps (wild guess). You soon get a warning on the dash about draining the battery in the last case. In the case of the ABS function I believe the purpose is to evaluate the aux battery SoC, and, with the new BMS update, to check the traction battery isolation resistance and cell voltage differential.
3. The system is awake and the LDC is active at 13.0 V. No aux battery drain is happening because that matches the "float" voltage. This can happen in Run or charge mode after driving/charging over 30 min.
4. As 3 above but with the LDC at 14.7 V. This will happen in Run or charge mode during the first 30 min, or Utility for the full duration. During Run mode after 30 min the system dithers rapidly between modes 3 and 4. The more accessories you have running the more volatile the dithering appears (using Torque Pro to evaluate).
 
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