How to replace the 12V battery in a Hyundai Ioniq Electric (& also 12V battery issues)

A dead or partially drained 12V battery is a fairly common issue on the Hyundai Ioniq Electric, on both the 28kWh and 38kWh versions. However, after owning these vehicles over the last 4 years, I have never personally experienced any 12V battery issues myself, until last week. For the first time, our Ioniq 12V battery went flat and the car wouldn't start.
As we already had a BM2 bluetooth 12V battery monitor fitted, we did get prior warning that the battery was draining, so for the previous two days we were monitoring it. So on the morning that it was flat and the car wouldn't start, it didn't come as a surprise and we were prepared and had the car running within a couple of minutes with a jump pack.
In this video I go through how to fit a new 12V battery in a Hyundai Ioniq Electric and explain the battery drain issues we were experiencing.
The Ioniq Electric uses a 12V 350A CCA 40Ah battery. The size is 054H. Suitable replacements are:
Exide EA406 (as shown in this video)
Yuasa YBX5056
Varta A13
Exide W054TE
Bosch S4 030
The Yuasa YBX3056 also fits, but at only 36Ah capacity, it would be better to get the YBX5056.
It is possible to fit a larger battery if you modify the battery tray, see • Hyundai Ioniq 28kWh - ...
BM2 bluetooth battery monitor amzn.to/3Qk3AVy
The Foxwell battery tester used in this video amzn.to/3yc8xti
To see other Hyundai Ioniq EV videos, see the playlist • Hyundai Ioniq EV 28/38kWh
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Timestamps
00:00 Intro
00:39 What does the 12V battery do?
01:16 No previous issues
01:32 BM2 battery monitor showing the battery drain
06:40 Jump pack to start it
07:04 New 12V battery
08:26 Tools required
08:58 Battery replacement instructions
14:25 Testing original & new batteries
17:43 Installing new battery
19:47 Why was it discharging?
21:10 Outro
#gogreenautos #evlearning #hyundaiioniq #hyundaiev #gogreenautosuk
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[@michaelbruton3537]

Hi Matt Just viewed this video I've got the battery monitor connected but never seen the calender in the app have I got an earlier version My 12v battery in my ioniq 28kw is over 7 years old and showing no sign of issues Your video has given me more insight of the app as many functions within the monitor app don't apply to the ev The drain curve was an interest so I'll study my history closely now Thank you for that info

[@GoGreenAutos]

Glad it helped. I've never experienced 12V battery issues on 28kWh Ioniqs. To be fair, this is the first time on a 38kWh Ioniq and its been fine since with the new battery fitted. But that wasn't the issue as the old battery has been fine since too and still like new.

[@mchipelo]

I just replaced the 12V battery on my 2021 Ioniq (same battery that was used in this video). It started giving the "low 12v" warning on the dash, and stuff started going crazy (radar not working). I measured 11,7V in rest and as low as 10v when starting the car. I've replaced it with a new one and no more issues.

[@ohyesitsme]

Thanks for the info Matt. Bookmarked for future reference.

[@simonpaine2347]

Not by design, a lead acid battery when used on an ICE engine, will extend its life by constantly removing the natural sulfation that occurs in normal operation. This happens when the car is started, because the battery is put under the greatest strain. This removes some of the buildup of the sulfatation. In an EV this just never happens, therefore the sulfation just slowly increases. Most modern battery chargers now have settings that will regenerate the battery and dramatically extend its life. The old battery would probably be like new after one or two regen cycles.

[@CeoofAlcorp]

I had this issue when i first got this car same model of car in april, given that I am not used to car battery issues it was really difficult to diagnose my cars bad battery. I had all manor of issues: car dying without warning, charging issues, and the 12 drain warning. i am happy to report the car runs just fine with the new 12v

[@kimedwards3937]

My old 38kw had the same problem with the 12 volt battery. After a service update for the battery it charged every 4 hours. Another problem when something stops the CPU going into sleep mode. DC current clamp meter is very handy when looking for faults.

[@flyborgify]

Great video as always. I put the same battery monitor on our 28kwh Ioniq after we experienced some issues with the vehicle shutting down whilst driving. 12v seems fine in ours. We had the car serviced, no faults found but issue has gone. Maybe a software update sorted it? Who knows. As to why your old battery now seems fine, again, who knows. Electricity is weird stuff. I don't really understand how it works but enjoy using it.

[@patrickh7368]

That was interesting to see, I half expected some system of keeping a 12v supply active whist changing that battery… my 28k Ioniq is still on its original 12v battery… 5 years old now… 😮

[@simoncanfer5030]

The intermittent nature of the battery failure might be temperature-related. It was cold around the 18 April. 4 years seems quite a short life, I reckon on 7 years. Our 2017 Ioniq's 12V lasted until last winter. Measuring state of charge and health on a lead acid is notoriously difficult and I certainly wouldn't trust any box of tricks that claims 1% accuracy! Battery University has some good info.

[@BrianSmith-zs5wg]

Something a bit similar on my Kia Niro EV, I had repeated low voltage problems (first sign on mine was drivers door not unlocking). The BM2 I fitted showed the battery volts gradually falling and the intermittent charging from the HV battery not bringing the voltage back up to where it had previously been. I shoved a mains charger on the battery for a couple of days while I was not using the car. Since then the rate at which the battery voltage drops has been lower (just like you saw). As I haven't had any further problems (3 months), I haven't changed the battery.

[@MartinPedersenTM]

Sounds like the car didn't go to sleep as it should. Maybe Bluelink keeping it awake?

[@thevideoark]

Could it be low weather temperature that was effecting the battery efficiency on a battery that may be on its way out.

[@Boggratt]

It sounds like one of the battery cells was dying possibly due to Sulfation which happens in lead acid batteries. The dying cell can’t hold a charge hence the accelerated drop in voltage when idle, you caught it early. I had the same issue with my 28kWh Inoiq a year ago with my battery dropping to 10-9V before I was able to get it replaced. Had I know that is was a straight swap I would have done the job myself! The BM2 is worth getting for peace of mind at least.

[@Peter-st1lt]

Great video really enjoy all your videos. Here's my 2 cents, I see the tester you used, will only give you a general idea on the condition of the battery, if there's a hidden issue, like poor solder joints internally the tester won't show that. I have a commercial load tester that I find more reliable by applying a proper load on the battery to see what it does. I changed the battery on my kona that was 4 and a half years old, it started acting up. When temps were cool out no problem, but on a mild day the battery would have a 12.3 volt charge I could unlock the door fine, then sit down and nothing worked. Measured the battery and it dropped in seconds to 5.8 volts. Charge it up and test it with the small tester like you have and it tests good. Grab my other tester put a good load on it and fails. I've seen this before intermittent fault somewhere inside. Just bought a new battery and no more problems.

[@GoGreenAutos]

I have looked into this and keep drawing a bit of a blank. While my little tester doesn't look much, it is actually a good one and quite expensive. Mine and most other testers do load testing in the form of a cranking test, however, this isn't applicable to EVs. I could use a traditional old drop tester, but again this isn't applicable when the 12V battery is in a EV as the greatest load on the battery is unfolding the door mirrors. Doing such a test on a battery may find issues, but then those issues should not arise in an EV as there is never that high loading. I appreciate what you're saying about your Kona battery though. What load tester are you using? I have looked at getting a better battery tester, but after spending hours of research, come away with nothing as it's a bit irrelevant when only looking at EV batteries. Most do cracking tests, which rely on the starter motor to put the load on the battery. Some apply a 125A load to the battery during a test. But the reality is that this will not happen when the battery is in an EV. What it really needs is a slow drain test on the bench over a couple of hours. But not found such a tester.

[@theelectrictransition]

I suppose the other thing I might have tried is putting it on a decent, conditioning battery charger. I have a Ring charger which puts high frequency pulses through the battery to try to dislodge sulphation from the plates. My smart ForTwo (featured on the channel last week) flattens it's battery quite fast - all ForTwos do - and I have been impressed just how many times the Ring charger has recovered a battery that should, probably, have been long gone. Sadly, Ring don't make my charger any more, but I think there are other manufacturers who continue to do similar things. I feel very much that I am teaching my grandmother to suck eggs, though - no mansplainimg intended!

[@GregAnslow]

Changed my 2 year old battery just as a precaution

[@Nikoo033]

How much of the 12V is used by having this Bluetooth BM2 device fitted? Do you not have the auto-charge function for the 12V on the Ioniq38 as for the Ioniq28 (via the dashboard menus).

[@GoGreenAutos]

The BM2 only draws 1mA and has almost zero effect. Yes, auto charge is on.

[@kevinbailey1961]

Maybe an intermittent fault on a 12v module. On a Kona forum I belong to, a module on the electric seat motor was randomly causing a heavy load on the 12v battery.

[@jezebabe]

Interesting video, thanks Matt. I wonder if you know about Ioniq Hybrids which don't seem to have a 12v battery at least as far as I can tell (but rather a 400v bank under the rear seats)? I have owned my 2019 Ioniq Hybrid for 2 years now but have an issue regarding use of a dashcam (Viofo) with a hardwire kit. The hardwire kit is set to monitor the 12v supply and turn off if it drops below a certain level. This worked fine in my old ICE car, but in the Ioniq it never turns off. I suspect the car is trying to supply it with a constant 12v which is why the dashcam never turns off. However, after around 2 to 3 days the car becomes "dead" - you even have to use the physical key to open the door (a bit of a pain as you have to remove a cover on the door handle first). Inside the car it's as if the battery has been removed - no sign of power anywhere. A quick call to the dealer when this happened the first time found an easy fix - there's a battery reset button under the dash. Press this, then press the start button WITH THE KEY and everything returns to normal. So now, to avoid the battery reset, I have to remember to unplug the dashcam after every journey and plug it back in before every journey. I know you focus on EVs on this channel, but I wondered if you had come across this before and have a solution (apart from not using a hardwire kit)? I suspect that this would happen with any hardwire kit that has voltage monitoring built-in. Thanks and sorry for the long post.

[@GoGreenAutos]

Sorry, can't comment on hybrids, especially some Ioniq hybrids as, as you've highlighted, they do things completely different. However, when wiring accessories like dashcams up, you need to check how the source power works. USB sockets, cigarette lighter sockets etc all work differently in terms of powering down. The Alfratronix PowerTector is a great device when wiring any accessories to a vehicle. See kzbin.info/www/bejne/ZnTHiZKqmM2dfZosi=d_MjeuXN0OQ_hqa0

[@jezebabe]

@@GoGreenAutos Ok, thanks for the information Matt 👍

[@fractalofgod6324]

Hmm, that's really strange. On my VW diesel you have to have the new battery coded to the car. I take it that it's not applicable to the ionic? Also are there any issues caused by the break in power supply to the car whilst changing out the battery? I've seen people connect an outside power supply to the car terminals before disconnecting the battery for replacement. Another really useful video so thank you very much and I'm glad you are still doing stuff on the ionic.

[@sp1es]

Having a 12v battery coded sounds absolutely insane and goes against right to repair

[@fractalofgod6324]

@@sp1es manufacturers have been going against your right to repair for many many years my friend. Nothing new there.

[@GoGreenAutos]

When he says "coded", what that means is you tell the BMS it has a new 12V battery installed and the charging profile for that battery then changes. BMW started doing this years ago and quite a few followed. So its not coded, rather 'tell the car it has a brand new battery, rather than the old one'.

[@GoGreenAutos]

No, this "coding" is not required. Nor is keeping a 12V supply. Nothing in the car is effected by disconnecting the battery.

[@fractalofgod6324]

@@GoGreenAutos good to know thank you. 👍

[@JanetNavier]

So i am a new ev owner of a 21 plate ioniq - only had it 2 weeks. Parked up yesterday morning as i finished work and by 9:30pm about to leave for work my car is totally unresponsive- after watching your video it sounds like my 12v car has gone flat as i did have a pop up message on my dash when i turned my car on to come home from work but it disappeared quickly that i couldnt read what it said just that i caught the words "12v" in it. How do i make sure my 12v battery is getting charged properly? My workplace is only 10 mins away in car but i work nights so i need it rather than walking to/from work in the night. Not to mention however long its been sat on the forecort before we purchased it.

[@michaelbruton3537]

Have you checked through the dashboard settings for " Battery Monitor turned On" This enables the vehicle to charge the 12v battery while in the vehicle is in the off state Look for a message on the dash telling you that the battery saver has been used Mine takes 2% off the range every time the message appears My 2017 28kw also shows a blue led in the windscreen to show the 12v battery is being charged while the vehicle is parked up Read the vehicle manual for information on Battery Saver Hope this helps you

[@JanetNavier]

@@michaelbruton3537ive never seen that setting, where is that? I ended up getting AA out to jump start it and took into hyundai. They found there was a module within the car system that was staying on causing a constant drain. Its been fine ever since so fingers crossed.

[@theelectrictransition]

Hey Matt, watch the video back. Did the negative terminal move a bit as you undid it? I wondered if it was a slightly bad connection on that negative terminal, perhaps in conjunction with cold weather. I remember from decades ago using vaseline to help avoid bad connections. Was that an old wife's tale? You didn't suggest it, so maybe it was all nonsense. I confess I haven't seen it done for a long time. You didn't mention the temperature in your video, and that makes a difference to lead acid batteries, doesn't it? Isn't that one of the main reasons ICE cars get flat batteries in winter? Not solely - more use of lights, blower etc - but one of them

[@erlendse]

Probably some software glitch. but pinpointing what would be very tricky without the tools used to develop the car. The too low voltage probably did reset whatever was acting up, making the system behave again. Strange how evrything can be a computer/software problem now.

[@jimrandall1739]

Can you attach the monitor to the battery while it is off the car?

[@GoGreenAutos]

Do you mean is it possible or are you asking for me to do that? I will make a follow up video.

[@jimrandall1739]

@@GoGreenAutos Thanks for the reply. I was just wondering, If the battery doesn't drain when it's off the car, could it be that the problem is with the car. But I suppose if the new battery drains it proves the same thing. I have a 2020 Ioniq, great car. Ive decided to buy it after a 4 year lease. I had a flat battery this week after coming back from Spain after 3 weeks. I usually leave it at about 85% for three months a year while we're away, never had a problem. I read on the forums that you shouldn't leave it fully charged for long periods. So this time I left it at 10%, thank goodness for the Booster Pack.Thanks for the great videos.

[@GoGreenAutos]

@@jimrandall1739 I'm making an update video. So far the old battery is fine off the car and the new battery is fine on the car. So its looking like the car caused the sudden drain, but its not done it again since in the last two weeks.

[@ozzie.freddo3972]

@@jimrandall1739 as @fernandinand said above, when the main battery is below 20%, it does not do the periodic topup of the 12V so if you left it at 10% then the 12V would have gradually discharged due to the small parasitic loads on it (like the small radio receiver that is running continually ready to receive a signal from your key fob).

[@fernandinand]

Mixed feelings here... Glad your battery lasted 3 years. My 2020 ioniq 38kWh is on it's third (3) 12V battery and I do not live on a cold climate (Portugal). First 2 were covered by warranty the last one on my own (~3 months) and it's already 83% SOH. On February visit to dealership, as usual software updated were included but that does not seem to be the issue. Things I learned online and at the dealership: - DC-DC internal boost does not work if traction battery is under 20% SOC - I get less notifications from Bluelink telemetry but that seems not the root cause - While DC-DC internal boost is charging the 12V battery, the car screen lights up (despite not displaying nothing)...weird behavior, should be fixable by software updates - Do a monthly full charge (~8h) to the 12V battery, specially during winter

[@MauFeitioO]

I also live in Portugal and I am interested in buying a ioniq 38kwh. Other than the issues with the 12v battery what is your opinion on the car? Also have you checked your HV battery SoH?

[@fernandinand]

@@MauFeitioO It's the best car for the money you can buy! I have 2 EVs, a 2014 Leaf (mk2) and the Ioniq and you can feel the differences on both in terms of build quality and reliability. Regarding warranty claims by far Hyundai is better than Nissan. Issues I had with mine solved under warranty: - Charge port actuator (lock) changed. It would not lock the cable while charging - Small issue on the black film cover of the rear door windows trim. Fitted a new one. - Software updates are done on dealership - Maintenance price at the dealership is lower than Nissan's The HV (traction) battery does not suffer premature degradation as Nissan's...mine is ~63k kms and still 100% SOH

[@fernandinand]

@@MauFeitioO Forgot the main deal breaker for some folks that do a lot of driving and rely on fast charging. The ioniq 38 e very slow at fast charging. You can only get ~44kW until 50% SOC, if the battery is warm enough...regular charging speeds are around 38kW-41kW on fast charging. I do not rely on fast charging, so for me this car is perfect!

[@MauFeitioO]

@@fernandinand Thanks for your valuable inputs, much appreciated! Fast charging would not be an issue since on a daily basis I travel around 70kms. On the weekends for roadtrips I think that the 200+ kms of range are enough since I would stop anyways after that. The issuesI find are more related with the cost of replacing the liquid coolant of the battery: I have seen ppl reporting 500€ for this on some hyundai dealers and it has to be done every 50k kms? Other than that there are good deals for Ioniq 38kwh version from 17k€. I am also considering tesla model 3 with LFP battery that would start from 25k€. Not sure which is the better deal

[@fernandinand]

@@MauFeitioO Yes, the liquid coolant and sensor is also an issue despite I was not affected. I know last year on regular maintenance they replaced the coolant and sensor on my car. Hyundai tries to front run known problems. Probably people complaining do not have the vehicles under warranty...

[@samb9073]

I change my battery on my at three year even There was nothing wrong with the battery Never had any problem

[@ThePeterOlausson]

I kid you not, even with collars on my clamps didnt't fit. I had a service technician that works with cars look at it. It was then a small film of alu-foil got used.