IONIQ 5’s 12-volt battery is dead: here's how I jump-started it

I just had this problem with my Niro, garage says everything is OK, which it obviously isn't! Thanks for this video, I've just ordered the jump starter 😃

What percentage did you have on the traction battery? I’ve heard that if the battery is under 20% it will not charge the 12v

So my Ioniq 5 had a 12v issue this morning. Was sitting at 89% on the HV battery so no issues there. After plugging the car into the wallbox for half an hour, it must've juiced the 12v enough to get going.
Interestingly, my app doesn't show the 12v battery under other?

it doesn't charge 12v unless you have more than 20%

Thanks for the video. I'm slightly less worried that my Ioniq 5 isn't totally dead now and the recovery guy will get me going again!

Too bad that someone in engineering decided to switch off aux charge when SoC is below 20%. Plus some Software bugs including the charge port status

I had this problem with my Ionic so called the AA out as I didn't have a jump starter ( I have now ). The guy said that ie if your parked up waiting for your wife to do a shop leave the car switched on...same if your cleaning it ( hoovering/washing ) that way the 12v will not be used...just the main battery plus it will be adding extra charge to the 12v while it is switched on.

Had a tesla for years never had this issue , might need to trade in for a model y.

Has this been resolved by now? :O

i have 64% battery after I did your jump cable test.. I was able to turn on the car. but when unhooked the jumper cable. the car turns off.. how did your turn stay on?

Hi Andrew my Ioniq5 12v woes continue. Hyundai Assist(AA) out four times in two days! They confirmed the 12v was goosed and not accepting a charge. My dealer would not accept the AA findings and said to book my car in…..six weeks until the earliest slot. I have just simply replaced the duff battery for a new one.
What is interesting the last AA patrol guy told me he was part of a team called in to help do PDI checks at Tilbury docks as Hyundai themselves could not cope with the work. He said the amount of replacement parts including main batteries was astonishing.
As I mentioned before a great video. Keep on posting. You and your family keep safe.

It's not normal top pay 50K for a new car and became Car Electric Expert...by force

Have you considered adding a remote battery kill switch (used in old petrol cars having parasitic battery drain)

how the hell can the 12vold battery die so fast.. what is wrong with that model.

Quick and silly question? Does the jump starter comes with the ionic 5 or you need to buy one?

For your information Andrew, my 2023 IONIQ5 fully patched just got the dead battery issue. My sin ? Leaving the car parked for 3 days with 11% remaining battery…

Just happened to me, '23 Ioniq 5, plugged in overnight charging scheduled. No notification via Bluelink of any problem whatsoever, dead as a door nail. Waiting for a guy to come charge it. Wondering if I should request a new battery under warranty.

Same here today with 77kWh I5, cold weather at 16%. No warning at all. Was not charging, just usb cable without load in the frontal usb. NICHT GUT! Will buy a booster as well and measure the “12V” regularly.

After reading loads and loads of rambling forum threads and a bucket full of videos none of which really helped I found your video. Wonderful, and thank you so much for sharing a simple, straightforward solution.
Cheers, Simon

This unbelievable it happen to me a couple days ago. The battery shouldn’t die! I never use bluelink and I came out to a dead car. I had to jump it and it’s now ok but this should be happening for an expensive car like this!

The 12V just died another time and I brought it into the shop again -- even though I was able to jump start it with a portable pack. This just shouldn't be and I believe we have to inconvenience Hyundai and make them pay for it every time.

Thank you. Mine died whilst on the granny charger overnight. No idea why. Not good enough really.

Originally the high voltage battery did stop charging the 12V battery when the HV battery state of charge dropped below 20-25% on the Ioniq 5. Software updates in 2023 lowered the threshold on the HV battery to 10% SOC but 12V battery problems seem to persist.

ThAnk You👍🏼 Worked like a charm. So relieving that it wasnt as hard as on my previous gas car. Brilliant.

I had the same issue with a 2022 Toyota RAV4 PHEV. Drove 200 miles and parked up on holiday for a week and didn’t use the car. When I went to load our cases the 12v battery was completely flat. Couldn’t open the boot or doors electronically. Had to use the emergency procedure to get in the car and then use jump leads to put the car in ready mode.
Took it Toyota who kept it overnight but said the battery was ok, and advised that it was ‘normal’ for electric cars! I went straight to Halfords to buy a battery pack like yours which fits in the glove box (don’t keep it in the boot!).
A couple of months later when we took the car in for a service we were told it needed a software update to tackle a 12v battery problem- surprise surprise:). Haven’t had the issue since but having the battery box in the glovebox sure is reassuring.

thanks, man, you really saved me 🙏

2019 Ioniq (Edit: Hybrid!) First Edition owner here.

This afternoon we had same symptom as described here: No response from the pressing the keys.

EVENTUALLY found the section in the Owner's Manual, on page 6-5, that describes how to use the '12v Battery Reset' button (no thanks to the useless index that includes no mention of it under the 'Battery' sub-heading!).

I got in using the physical key, pressed the Battery Reset button, then pressed the start button. The alarm went off and the display complained the key wasn't present. So I put the physical key back in the fob (I don't think that actually made any difference whatsoever), then pressed the Unlock button. The alarm stopped, then I was able to start the car.

My next step was to drive the car around for a little over and hour, making a couple of stops (petrol, Sainsbury's, the chemists) with no further problems.

hi, after owning the Hyundai Ionic 5 car for 3 years now, I had the first 12v battery issue today. The car was on charge and had completed for 80% as usual. Today when I wanted to start\power on the car using the fob it did not work. It was dead. Had to call AA for help. He came and jump started the car using his battery kit. He said the 12v battery was drained. Then he told to drive the car for an hour so that the 12v battery is charged. It looks ok now. The car main battery was at 80% though. Such an expensive car but not sure why Hyundai chose to put cheap quality 12v lead battery. Why cant they put a permanent fix to it. Very disappointed and nervous if it happens again.

Thank you so much, this just happened to us and we had no idea what to do until we saw your very helpful and easy to follow video....what a legend you are! The car is charging as I type.

Things that are bound to happen when you leave your car without turning it off.

All the talking dont mrch the straight to the point

Toyota Hybrid have the same issue with the 12v battery draining

Rather than a battery pack jumpstarter, consider a supercapacitor jumpstarter. You don't need to remember to keep them charged; instead they charge up when you need them from the residual power in the "dead" 12v.

Nothing worse than a jumpstarter with no charge when you need it because you haven't checked it in a month or two.

A LIFE SAVER VIDEO! There is a recall currently for this very problem with the 2023 IONIG 5.
I will buy one to avoid a tow, then drive it to the dealer where the Safety Recall notice says the issue is the ICCU which charges the vehicle's 12-volt battery. My car is dead, currently. The actual fix says, the "time required to perform the software update on your vehicle will take less than one hour..."

EcoNour XS60 Car Battery Jump Starter - 6000A Battery Jumper Starter Portable, 12V Truck, SUV, Car Battery Charger with SOS & Jumper Cable, Ideal for Up to 8.0L Gas & 8.0L Diesel Engines (40000 mAh)

Q: will this work for an EV car, Hyundai Ioniq 5 deep cycle 12V battery? it is not the same as a reg. 12v

EcoNour answered:
 

Yes it works."

What ended up happening? When AAA jumped the battery, I drove it from where it was parked to my home. When I turned off my Ioniq 5, and the 12 v went back to 0. Thus, this is recall issue as previously stated. My car is sitting dead once again. I will have to call AAA again on Monday morning so I can drive it to the dealer. (AAA trucks do not carry those giant battery charging units.)

Im curious if you guys are charging your evs in a css charger of sorts and go inside your car while its charging but obviously you don't press brake not start the car in that process, are you then using the 12v battery while sitting in the car and messing around menus etc?

Thanks for the video. I have been a keen viewer of your channel and particularly your videos of the Ioniq 5 (I have had my Ioniq 5 since July 2022). After two years ownership with no battery problems, the 12v battery died. I don't know why. It wasn't directly after a charge (main battery was at 38% at the time). With our usage, all short trips, I normally charge once a week back up to 80%.

I have just purchased a jump starter power pack in case it happens again, and also the battery monitoring gadget to keep an eye on the battery level. I will speak to the Hyundai garage and ask if there are still known problems (for my 22 model) and if there are any updates available.

I have loved my Ioniq 5 until now. Would be good to hear if the issues with 12v batteries are now resolved in the latest models.

Came across this while researching battery problems with the Toyota Yaris Cross range of hybrids, and it seems that a flat accessory battery is to be a pretty common problem with a significant number of makes of hybrids. Poor quality batteries plays a part but personally I reckon the root cause is these car have so much tech running in the background 24/7, even when the ignition is off. I have a friend with a VW hybrid and he too had problems with the accessory battery going flat.Great video Andrew, with some useful comment and advice which every EV owner should take on board.

I've just ordered a Toyota Yaris Cross and joined a few facebook groups to learn more about them. Nearly ever other post of them is about the appalling 12v batteries on them. So it seems like many evs/plugin hybrids and "self-charging" hybrids have the same problem.
I spoke to the Dealership I am buying from and asked them what can be done. They say they will provide me with a solar charger that I can plug into the cigarette lighter in the boot to keep the charge up. They say that if there's a day I won't be using the car at all, to plug it in then. I have to unplug it when I get in the car next time. Not sure if that will work. But will give it a try. I've also purchased a noco battery booster to keep in the car just in case. Hope my new car will be worth all of this effort!!

Had the battery replace - went on a 4hour drive - fine - went on a short trip with 13 left on charge and car will not respond - heartbreaking

This happened to me with a Prius PHEV so not just BEVs. I had already bought a jump-starter as I was going to be leaving the car at Heathrow for 3 weeks and had previously had my cars jump-started by the valet parking folk after 2 long stays. I ow have a Kona (21 plate) which has a little light in the centre of the front emblem that shows the 12v is being topped up - I've actually only seen this on once so probably working, don'y know how often hence keeping the jump-starter.

What..12v in an electdic xar.

What is causing the drain on the 12 volt battery? I have a brand new battery in my BZ4X (2024) and it runs out every night

Not just Kia and Hyundia.....I got stranded i my Jag I-Pace last week cos the 12v battery had failed without warning. A 3 year old car!!....the original battery on my Merc AMG E-Class lasted 12 years. So now I'm learning how to access the car when it's dead (my 'frunk' has an electric release, but I now know where the emergency release is hidden!), that I need to get a booster pack to keep in the frunk, and I'm going to fit a cheap bluetooth battery monitor so I can see what the 12v is up to.
EVs are shite.....I have an £80,000 car I now don't trust. How many Merc S-class owners have ever fitted a battery monitor....none, I'd imagine.

Mazda as well...😮

Don’t give the old-school tech too much of a hard time… it’s not fault of the 12v battery, it’s the poor design of how it’s being (mis-)managed by the new tech!

Welp this came in handy, Thanks!!! I’d like to add that not all scenarios will turn the car right on so effortlessly. If the volts are low AND the car isn’t charged like 0% jumpstart as you charge until you’re at 2 miles. Once you’re at 2 miles test the battery to see if it’s at 12+ volts if so remove the tester to see if the jump box holds charge and remove as you continue your charge…You should be charging without alternative at this point. Good luck….👍 up ⬆️ the post if this helped or helps anyone.

My Prius 12 volt failed whilst on vacation, it was 8 years old so may be it was time.