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2022 Ioniq 5 AWD Balance Vision
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So I had the dreaded dead 12V battery today. I went past my Ioniq to go out via the garage to check the mail mid day today and knew something was up because the single red strip of light underneath the brake lights/Ioniq 5 lettering was lit. I was like hmm, that seems weird and unusual. Tried to open the car door and no response, so as I suspected, dead 12V. Needed to use the mechanical key to open the door, pop the hood, and get the 12V jump start battery from the glove box. Connected the 12V jump starter to the battery and started hearing some clicking noises, I suspect I could have disconnected the jump start battery then but I went ahead and turned on the car first. Oh, and the alarm started honking at me as soon as the 12V was live, not sure if closing the driver's door would have prevented it but just be aware so you don't startle yourself.

Not entirely sure what caused it to go dead. I realized I left the lights on (not in auto like normal) as it was raining but bright enough for auto lights not to be on yesterday when I drove it. I assume those turn themselves off though like on most modern cars. Other than that, I have a hardwired dash cam but it has a low voltage cutoff switch and an OBD dongle that does stay on even when car is off. Would love to know why the 12V died but not sure I'll ever know.

One more thing, I wasn't getting any response from the lock/unlock button on the passenger side door handle this evening, but the driver's side was fine. I suspected it might need a reset, so I disconnected the negative terminal on the 12V battery when i got home, reconnected it and worked like a charm afterwards.

Any ideas what drained my 12V battery? Anyone else had similar issues with the lock/unlock button after a dead 12V?
Your problem is for 99% sure the already known charge door problem. The charge door just touched your switch at the inside, which causes a opening/closing sequence at high frequency which result in a drained 12V battery. The solution, until Hyundai solves this problem, is to stick some felt pads on the inside so that the charge door does not touch the switch anymore, see video (in German), but you will understand.
 

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I would like to modify the BM2 and attach a 12V power plug, and plug it in inside the car. Would that give me the same results?

Probably not, but why would you want to do that? It attaches to the battery terminal easily and then there is no need to touch it again.
 

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Where is the best place to store a jump starter with LiPo battery chemistry? Wouldn't storing it in the car be a fire hazard, as the storing temperatures for these are typically less than 40 degrees celsius? Does the frunk get that hot on a hot summer day? Glove compartment can get quite hot. Not storing in the car kind of defeats the purpose however.
I purchased the Shell SH916WC from Costco

Battery Type: Lithium-Polymer
Battery Capacity: 16000mAh, 59.2Wh
Operating Temperature: - 20ºC ~ 60ºC
Storage Temperature: - 20ºC ~ 40ºC
Charging Temperature: 0ºC ~ 45ºC
 

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Hi
I had the 12v fail a week ago and after restarting took the car to the dealer for investigation.
They advised me a software update has been published by Hundai for cars in a specific VIN range. Unfortunately I was unable to get a copy of the service update document
At no time was I contacted by Hyundai advising me the update was available, which I think is poor customer service, considering they have my VIN and contact details
 

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2018 Kona Electric
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I would like to modify the BM2 and attach a 12V power plug, and plug it in inside the car. Would that give me the same results?
The entire point of a BM2 is that it logs voltage every 2 seconds 24/7 without disturbing the 12V system by opening a door, etc, and only using 1.5mA of current.
Anyone who installs one and checks it every few days (takes about 30 sec each time) will learn a lot about how the car takes care of the 12V battery. It saves a lot of speculation.
 

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So I had the dreaded dead 12V battery today. I went past my Ioniq to go out via the garage to check the mail mid day today and knew something was up because the single red strip of light underneath the brake lights/Ioniq 5 lettering was lit. I was like hmm, that seems weird and unusual. Tried to open the car door and no response, so as I suspected, dead 12V. Needed to use the mechanical key to open the door, pop the hood, and get the 12V jump start battery from the glove box. Connected the 12V jump starter to the battery and started hearing some clicking noises, I suspect I could have disconnected the jump start battery then but I went ahead and turned on the car first. Oh, and the alarm started honking at me as soon as the 12V was live, not sure if closing the driver's door would have prevented it but just be aware so you don't startle yourself.

Not entirely sure what caused it to go dead. I realized I left the lights on (not in auto like normal) as it was raining but bright enough for auto lights not to be on yesterday when I drove it. I assume those turn themselves off though like on most modern cars. Other than that, I have a hardwired dash cam but it has a low voltage cutoff switch and an OBD dongle that does stay on even when car is off. Would love to know why the 12V died but not sure I'll ever know.

One more thing, I wasn't getting any response from the lock/unlock button on the passenger side door handle this evening, but the driver's side was fine. I suspected it might need a reset, so I disconnected the negative terminal on the 12V battery when i got home, reconnected it and worked like a charm afterwards.

Any ideas what drained my 12V battery? Anyone else had similar issues with the lock/unlock button after a dead 12V?
I've had this same issue on my 2020 Ioniq Electric. Both times the 12V battery died was right after the car was charged to about 95% on my 110V plug in my garage. I think there may be a software glitch that either drains the 12V during the charging of the main battery if the cycle isn't completed, or the 12V only charges during the very last phase of the charging cycle of the main battery, or for some reason a command is issued that prevents the 12V from recharging while driving. Somewhat to my surprise, Hyundai replaced the battery under warranty, which suggests it is a significant problem.
 

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Dang, I thought about putting a piece of felt ON the close door button because I find it hard to push those square dots to open the door. I guess that's a bad idea as it may cause battery drain? (I don't think it will but more of a software glitch)
 

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The 12V battery on my Ionic 5 SE AWD (US) keeps getting drained by a strong "vampire" current, until it dies. I purchased the car in March 2022, had no issues with the auxiliary battery until July.
A few times a week I would see the yellow light on the dashboard turn on, signaling a top-off of the 12V battery.I read about the dead battery issue reported by a number of users, so I bought a battery charger pack to jump start the battery in case I needed it.
Good thing I did, because in July I found the battery dead. Pretty much every day, unless I drove for more than 30 min, I had to open the driver door with the mechanical key, open the frunk,jump start the battery, hop in the driver's seat to turn on the main battery, disconnect the jump-start battery, close the frunk and get ready to drive.

After a week of torture I managed to book a service to inspect the problem.I had to leave the car for 3 days, as going through the diagnostics, charging and discharging the battery took some time.
In the end, the dealer was unable to identify the problem, but they installed a SW update (Control Shifter) and probably also the BMS update, both of which can only be done bythe dealer.

I kept my car updated on the infotainment side (May 2022 was the last update), but I doubt that this has anything to do with my current problem.
After I picked up the car, I noticed that the yellow light would go on much more often than before, probably 10 times a day, and almost every time I entered the car. At first I though that this was a good thing, as the large battery was taking care of tapping off the little one, to prevent me from being stranded. Fast forward 3 months, I noticed that the yellow light would no longer show up.
One week later I got a message from the Bluelink app saying that my battery was low. 58%. Yes, the main battery was at 58% (I never go below 30%) which I did not think it meant "low" battery charge.
But next morning my 12V battery was dead. I jump-started the battery, the main battery was still at 58%, so clearly the low-battery message was triggered by the dying 12V battery. But Bluelink seems to mix up the two.

This time the situation was even more extreme than in July. Even a fully charged 12 V battery (4 hours with a good charger) would die within the day, with the car locked, turned off, no use of Bluelink to check status etc.
I do have the BM2 voltage monitor installed, that many users suggested, but it does not help me because when the battery dies all the logged data disappears, so I haveno information about when the battery died.
I purchased a current meter, discovering that with the car turned off the vampire current from the 12V battery to the car ranges between 3 and 8 Amps, way more than the 50 mA used by the car circuitry when nothing is on. Strangely, after I disconnect the "-" cable from the car and reconnect, the current level changes, to 4 amps, 6 Amps, 5 Amps, 7 Amps after hearing various clicking of relays in the fuse box.
Having read about the misaligned charger port door that can cause high current when the flap touches the open/close button, I suspected that that could be the problem. But no, regardless of whether the flap is open or closed or kept slightly open to avoid touching the button, the leak remains substantial.

I tried all other tricks explained in this forum, refreshing the status on the Bluelink app, turning on the A/C to "unlock" something in the battery management system, staying away from opening the charge door via BlueLink app or voice command, that in some cases seem to leave something use a lot of current when the car is idle. But nothing works.
I brought tthe car to another dealership, closer to my home. They ran the car diagnostics, which reported that everything was working and the 12V battery was still in reasonable conditions, despite the numerous full-discharge cycles. As the problem kept happening every day, I brought the car a second time, for a full-day inspection. This time they confirmed that there is a problem, but they were unable to identify it.

Now I am scheduled for another service, lasting probably 2-3 days, to figure out what causes the problem by removing all fuses one by one. Whilst I am waiting for the service date, I tried myself extracting and re-inserting all the fuses in the main fuse box, close the the battery where the current meter is connected so that I can detect changes in current leaking. The only fuse (40A) that makes the current go down to 1-2A is labeled B+ (not sure what it is for).
Next step would be to do the same thing with the fuses next to the steering column, but then I cannot easily see the display of the current meter attached to the battery, in the trunk.
I am running out of patience and ideas on how to identify the problem. But it is probably not a simple issue, like a light stuck on, or a fan running for no reason, as every time I disconnect and reconnect the 12 V battery the current changes to a different stable level,accompanied by clicking of relays that indicate that different units are turning on or off. More likely to be a power management software problem.
The fact that the yellow light of the main battery management system never shows up again, whichever voltage the 12 V battery is at (13V, 12.5V, 12V, 11V, 4V...) makes me think that the battery management system itself may be faulty.

I am reporting this in case others encountered the same issue, and were unable to fix the problem using solutions presented in the past on this forum.
If the next service manages to find the cause, I will be happy to report, in case it may help others.

I love almost everything in my Iniq 5. but this battery problem is driving me nuts...
 

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The 12V battery on my Ionic 5 SE AWD (US) keeps getting drained by a strong "vampire" current, until it dies. I purchased the car in March 2022, had no issues with the auxiliary battery until July.
You did have issues, but a new battery can put up with abuse for a couple months before it starts failing.
 

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23 Cyber Gray Limited AWD
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>The only fuse (40A) that makes the current go down to 1-2A is labeled B+ (not sure what it is for).
@sicconi With my I5 finally due in, possibly Dec, I signed up for maintenance again, service information. (BTW, sign up as public, not independent repair facility if you are a DIY EVGearhead owner like myself, it is less expensive.)

If you want to try to look around a bit more, no idea if I can help you find the load, send your VIN to me on conversation. Can you say more about the 40A fuse, which fuse box, maybe snap a picture of it. "B+" generally refers to a bus, probably the heavy black line at the top of these schematics. There are several 40A fuses, here are a couple of examples (pgs 1, 3):
Rectangle Slope Font Parallel Pattern
Rectangle Slope Font Line Parallel
 

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The 12V battery on my Ionic 5 SE AWD (US) keeps getting drained by a strong "vampire" current, until it dies. I purchased the car in March 2022, had no issues with the auxiliary battery until July.
A few times a week I would see the yellow light on the dashboard turn on, signaling a top-off of the 12V battery.I read about the dead battery issue reported by a number of users, so I bought a battery charger pack to jump start the battery in case I needed it.
Good thing I did, because in July I found the battery dead. Pretty much every day, unless I drove for more than 30 min, I had to open the driver door with the mechanical key, open the frunk,jump start the battery, hop in the driver's seat to turn on the main battery, disconnect the jump-start battery, close the frunk and get ready to drive.

After a week of torture I managed to book a service to inspect the problem.I had to leave the car for 3 days, as going through the diagnostics, charging and discharging the battery took some time.
In the end, the dealer was unable to identify the problem, but they installed a SW update (Control Shifter) and probably also the BMS update, both of which can only be done bythe dealer.

I kept my car updated on the infotainment side (May 2022 was the last update), but I doubt that this has anything to do with my current problem.
After I picked up the car, I noticed that the yellow light would go on much more often than before, probably 10 times a day, and almost every time I entered the car. At first I though that this was a good thing, as the large battery was taking care of tapping off the little one, to prevent me from being stranded. Fast forward 3 months, I noticed that the yellow light would no longer show up.
One week later I got a message from the Bluelink app saying that my battery was low. 58%. Yes, the main battery was at 58% (I never go below 30%) which I did not think it meant "low" battery charge.
But next morning my 12V battery was dead. I jump-started the battery, the main battery was still at 58%, so clearly the low-battery message was triggered by the dying 12V battery. But Bluelink seems to mix up the two.

This time the situation was even more extreme than in July. Even a fully charged 12 V battery (4 hours with a good charger) would die within the day, with the car locked, turned off, no use of Bluelink to check status etc.
I do have the BM2 voltage monitor installed, that many users suggested, but it does not help me because when the battery dies all the logged data disappears, so I haveno information about when the battery died.
I purchased a current meter, discovering that with the car turned off the vampire current from the 12V battery to the car ranges between 3 and 8 Amps, way more than the 50 mA used by the car circuitry when nothing is on. Strangely, after I disconnect the "-" cable from the car and reconnect, the current level changes, to 4 amps, 6 Amps, 5 Amps, 7 Amps after hearing various clicking of relays in the fuse box.
Having read about the misaligned charger port door that can cause high current when the flap touches the open/close button, I suspected that that could be the problem. But no, regardless of whether the flap is open or closed or kept slightly open to avoid touching the button, the leak remains substantial.

I tried all other tricks explained in this forum, refreshing the status on the Bluelink app, turning on the A/C to "unlock" something in the battery management system, staying away from opening the charge door via BlueLink app or voice command, that in some cases seem to leave something use a lot of current when the car is idle. But nothing works.
I brought tthe car to another dealership, closer to my home. They ran the car diagnostics, which reported that everything was working and the 12V battery was still in reasonable conditions, despite the numerous full-discharge cycles. As the problem kept happening every day, I brought the car a second time, for a full-day inspection. This time they confirmed that there is a problem, but they were unable to identify it.

Now I am scheduled for another service, lasting probably 2-3 days, to figure out what causes the problem by removing all fuses one by one. Whilst I am waiting for the service date, I tried myself extracting and re-inserting all the fuses in the main fuse box, close the the battery where the current meter is connected so that I can detect changes in current leaking. The only fuse (40A) that makes the current go down to 1-2A is labeled B+ (not sure what it is for).
Next step would be to do the same thing with the fuses next to the steering column, but then I cannot easily see the display of the current meter attached to the battery, in the trunk.
I am running out of patience and ideas on how to identify the problem. But it is probably not a simple issue, like a light stuck on, or a fan running for no reason, as every time I disconnect and reconnect the 12 V battery the current changes to a different stable level,accompanied by clicking of relays that indicate that different units are turning on or off. More likely to be a power management software problem.
The fact that the yellow light of the main battery management system never shows up again, whichever voltage the 12 V battery is at (13V, 12.5V, 12V, 11V, 4V...) makes me think that the battery management system itself may be faulty.

I am reporting this in case others encountered the same issue, and were unable to fix the problem using solutions presented in the past on this forum.
If the next service manages to find the cause, I will be happy to report, in case it may help others.

I love almost everything in my Iniq 5. but this battery problem is driving me nuts...
The fact that you no longer see the orange light indicates that the BMS has given up on the battery. It gives up after 10 consecutive ~ 20 minute attempts to get the battery charged above a certain level. Disconnect the negative cable from the battery terminal. I would then hook up a desulfating charger to the battery and let it run for a couple of days. It should give you the health of the battery as well. If the battery is still healthy then reconnect the negative cable, and your BMS will have reset so it should charging the battery when needed. A Ctek MXS 5.0 or Optimate 6 (I have this one) are decent desulfating chargers. Its good to get one of these even if your battery is good. I charge my battery every month or so since EVs tend to abuse their 12v batteries more than ICE cars.
 

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Also taking current measurements with the hood open and key FOB next to car will skew the results. A forum member
Ixlr8 has taken reliable measurements of a good working Ioniq 5. Also based on his measurements, important to keep the SOC above 15%


"Preliminary observations:
Vehicle shut off, nothing plugged into obd2 or usb.
Soc 60%
Immediately after locking doors amperage drain was 5.7A
At 2 min 3.2A
At 8 min 0.035A
At 1.08 hours 0.009 amps or 9mA.
12v battery at 1.08 hour measurement was 12.67v
12.67v x 0.009 mA = 0.114 W or 114 mW.

I have data logging Amperage readings for over 12 hours to learn how the vehicle drains the 12v.

At 14 hours, touching dot on door handle adds 110mA to drain for 2-3 seconds then back to 9mA.

Accessing Bluelink app from Android phone make amperage spike to 7.2A. Then it takes the same time period to get own to 9mA sleep, 1.08 hours. "

"Side note, I can confirm from my own experience, monitoring and logging, the HV battery will not charge 12v when soc is below 15%. Therefore, if 12v battery has been ran down through heavy accessory use and you are at < 15% soc your 12v battery will run flat unless you turn on your car, place it in Ready mode. Again, I have confirmed this from my own monitoring of 12v battery and amparage drain in this scenario"
 

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@sicconi With my I5 finally due in, possibly Dec, I signed up for maintenance again, service information. (BTW, sign up as public, not independent repair facility if you are a DIY EVGearhead owner like myself, it is less expensive.)

If you want to try to look around a bit more, no idea if I can help you find the load, send your VIN to me on conversation. Can you say more about the 40A fuse, which fuse box, maybe snap a picture of it. "B+" generally refers to a bus, probably the heavy black line at the top of these schematics. There are several 40A fuses, here are a couple of examples (pgs 1, 3):
View attachment 46621 View attachment 46622
I see this 40A in the manual
Font Screenshot Number Rectangle Parallel


Rectangle Schematic Font Parallel Pattern
 

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23 Cyber Gray Limited AWD
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Maybe all this tech stuff needs moving to its own thread.
Mike, What is the best way to post this kind of information? Should it be in IONIQ 5 Powertrain and Technical Discussion, or IONIQ 5 Charging And Batteries? I don't think I can delete and re-post. If that is the case, Moderator, feel free to move or delete my posts. okay, I was able delete all of the content of the recent posts, Moderator, please delete the empty posts if possible, Thanks!

@MIkeS thanks for keeping me out of trouble. Moderator, thank you for deleting my blank posts. I reposted, with better description in technical discussion:

12V B+ Distribution

Fuses in the charge port door path
 

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2022 Ionic 5 Limited 2 wheel drive
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My Ioniq 5 is sitting at the dealership with a dead 12 volt. It’s the third visit for my car with 2400 miles on it. They have no idea what is causing the battery to die.
 
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