Yesterday, while finishing a hike with my Valentine, she spotted something I’d never seen before. “Hey David, what’s that green light on that parked car?” I turned to see a tiny green LED at the nose of a Hyundai Kona EV, inside its badge. The car appeared to be off and unoccupied. “Wait… did that car just turn that light on by itself?” I wondered. Sadly, I had no answer for my date, because I had absolutely no clue what this LED was all about.
The car was parked just outside of LA’s Will Rogers state park, named so because the land once belonged to early-1900s actor/radio host/writer/social commentator Will Rogers. My girlfriend and I had just descended one of the Santa Monica mountains after just missing the sunset, and things were getting dark. As we approached her Lexus RX350 in the parking area, she noticed a bright green light on the front of a Hyundai Kona EV, and, unsure what it was, I approached it and took this blurry photo:
“Why is this on?” I kept asking myself. “There’s nobody in this car!” I had a lot of questions. “Does this stay on? Does it drain the battery (eventually)? What’s it for?”
As I paced back and forth in front of the car, frantically scribbling my hypotheses into a notebook and listening to the echoes of myself yelling “No, that CAN’T be it! Come on, David, THINK!” I eventually came to my sense. No, I didn’t figure out what the LED was, but I figured out that I was on a Valentine’s Day date with someone who was probably deeply, deeply confused at this point.
I shut my notebook, turned to her while wondering how long I had been caught in that Hyundai LED-induced trance, and offered a questioning smile.
Whew, she understood. Well, she didn’t understand, but she… tolerated it. And so our date went on. I had given her some chocolate from her favorite chocolate spot and a dozen roses, and I was about to take her out for a fancy dinner. Her gift to me? A pair of UGGs (I shit you not; but the short type. I love them) and the greatest Valentine’s Day gift I’ve ever received:
Wait, hold on. I’m realizing I just pasted the version of that photo that one of my colleagues jokingly modified with my photo. Whatever, I’ll keep that there. ANYWAY, the Hyundai’s LED. I did a little digging, and what I found is that it’s called the “Auxiliary Battery Saver.” Here’s what it’s for:
Apparently that green LED turns itself on when the high-voltage battery is charging the 12-volt battery through the DC-DC converter. As a refresher from our “How EVs Work” primer (which is the best explanation of how EVs work on the entire internet), here’s what a DC-DC converter is:
But EVs still have a bunch of low voltage 12V systems, in large part because it’s still cheaper and simpler for car-makers to use off the shelf 12V lighting, wipers, entertainment and other systems that are often shared with their non-EV vehicles. So we need a source of 12V power on board. Step up the next of our unique EV systems – the DC:DC convertor. This is yet another ‘box’, this time – as the same suggests – a piece of power electronics that steps down a DC supply, turning the high-voltage output form the battery, often nominally 400V or 800V, to a (still DC) 12V supply – usually calibrated closer to 14.2V in reality.
A DC-DC converter’s analogy in an ICE vehicle is the alternator – this is the unit that keeps the 12V battery (or batteries in certain EVs) topped up, and the lights and wipers on. If it fails, the failure is similar to blowing an alternator belt on your ‘regular’ car – you have a limited time left before that 12V battery will drain, your lights will start to look like yellow piss-holes in the snow, relays will start to click sadly, and you need to look for a safe place to park up and call the rescue truck. It’s so critical that many EVs will actually have two, redundant, DC:DCs.
In addition, when the climate control has been scheduled prior to the driver entering the car, the light comes on — again, to make it clear that current is flowing from the high-voltage battery:
Why would you need this light? Well, some folks on the messaging boards hypothesize that it’s likely used to notify mechanics that high-voltage is flowing. “Strictly speaking its there to tell service personel that the traction battery is live and being used. it will come on as said every day to check and top up 12v battery,” writes user struthbingham.
I have no clue if this is right; it seems a little subtle to be a significant safety item, and to me seems more like just a notification to make it clear that high voltage is flowing. That said, the Hyundai Ioniq 5 and Kia EV6 also feature an “Aux. Battery Saver” (but on their dashboards), and their user manuals specifically warn against touching the orange wire, so maybe this is a safety thing on some level:
Anyway, there you have it: A car that automatically turns on a Rudolph The Reindeer-esque light on its nose even when the car is off. I’d never seen anything like it before, so I figured I’d share. So the next time you see a Kona with a yellow/green light on its nose, you now know it’s because it’s either charging the battery or preconditioning the cabin with its climate control.
Exciting stuff!
Oh, and the date went great. The dinner was delicious.
probably just some store bought DC to DC charger that has the Green On LED illuminated when it is in fact on.
I thought it was to indicate that this was a “USB-Cable-stealable” vehicle.
“LA’s Will Rogers state park, named so because the land once belonged to early-1900s actor/radio host/writer/social commentator Will Rogers”
Ah, yeah, not too many people today know a whole lot about Will Rogers; that description of him is a bit of an understatement about a pretty fascinating person. He was comparable in terms of his humor and commentary to Mark Twain even if his fame wasn’t quite as enduring as Twain’s. He was one of the most famous and most popular Americans back in the day; he was one of Hollywood’s highest-paid actors at the time of his death in 1935. He died in a plane crash in Alaska along with his friend, Wiley Post, an aviation pioneer whose fame rivaled that of Charles Lindbergh (plus, Post was presumably less, uh, eugenicist than Lindbergh, especially since Post was part Cherokee, as was Will Rogers who was born as a citizen of the Cherokee Nation in the Indian Territory of what’s now Oklahoma.) Wiley Post was also pretty interesting himself; he broke the Graf Zeppelin’s circumnavigation record by flying a single-engined plane with a co-pilot around the world in a little under 9 days in 1931 and then broke it again in 1933 by flying solo (!!) around the world in just under 8 days. He also pioneered the use of pressure suits, as his plane was unpressurized, and in the course of reaching altitudes as high as 50,000 feet (15,000 m) he discovered the jet stream. https://www.flickr.com/photos/sdasmarchives/49049646957/in/photostream/
The significance of that one plane crash claiming two such enormously famous and accomplished people is not easy to convey today without bringing up more contemporary comparisons such as Princess Diana’s car crash in 1997. When Rogers and Post died in ’35 my parents were young children but they, along with peers, would still talk about that day more than 70 years later.
Awesome comment!
If it were funny it might be a candidate for COTD, but alas those of us who are humor impaired seem not to be eligible.
Thank you! Yes, alas, I do not have the wit of Will Rogers.
Such a good comment.
Thank you! Goodness knows those two people deserve greater recognition & appreciation.
Such a good & informative comment should still be eligible for COTD. I’d urge that it be considered today!
of course, reading a comment a day later, I completely miss that it was.
I’ll try to keep up in the future!
“I am putting myself to the fullest possible use, which is all I think that any conscious entity can ever hope to do.”
I’m sorry Dave, I can’t open the airlock to anyone wearing UGGS.
From trench foot to UGGS… What a journey!
Someday I too hope to find someone who
understandstolerates me.Happy day after Valentine’s Day everyone.
Prehensile Cylon.
Oh, David. You’re doing it wrong.
“That? Oh, I love you so much that it generates an affection induction field that charges EVs in proximity. That’s an AIF uptake indicator”
I found the “emergency response” manual for my 2012 Prius v, and I think its messaging reads similarly to that…basically saying, “if you see the “READY” light, the high voltage battery system can still be running, so use caution.” Like my firefighter friend telling me about extra classes they’ve had because if you use Jaws of Life on the wrong part of a Tesla, you come down with a bad case of the death.
I absolutely hate that “do not modify your vehicle in any way” messaging. I installed a small subwoofer and two dashcams in my car, and at a service appointment they made a brief comment about the extra wiring and such and I wanted to say “oh I’m sorry, does me greatly simplifying any potential insurance claims bother you?” I’m thinking of adding one to each side now, too.
The subwoofer is a compact under-seat model, so I have zero concerns about its impact. Planning to add a second one when the weather gets warmer.
I’ve had this car for 3 years and wondered this many times. Thanks for the service journalism, David.
Time to RTFM
I don’t know why, but now this is stuck in my head
https://www.youtube.com/watch?v=ZW0DfsCzfq4
Well that makes more sense than the little light on the dashboard of my Toyota that blinks when the doors aren’t locked. A timesaver for people looking for unlocked cars for sure.
I mean, every car with a fob I’ve owned had a light that blinks when it’s locked, so in that case, it seems stupid but still safe since I would assume a thief would think it’s the same as the others.
This just solved a mystery for me! The other night I looked out the window at my Kia Niro EV and saw the middle charging indicator blinking. It was not plugged in at the time, and anyway, the middle should only blink when the passenger side is already illuminated as they indicate charging state. I wasn’t curious enough to look it up in the manual, but it had to be the indicator for the 12v battery charging like on the Kona EV.
I wonder if “the car is off” actually still means what we’d expect when talking about these sort of EV functions. What meaningful difference is there between pre-conditioning the climate system + charging the 12v system on this EV versus idling in a parking lot with the a/c on in an ICE? Put differently, what defines an EV being “on”?
Usually an EV is “on” when the high-voltage battery contactor is closed. That’s just a big switch that stops or allows current to flow out of the big battery. That’s why a 12v battery is necessary in the first place instead of running things straight off the DC-DC converter(s).
The “ON” isn’t a direct correlation anymore between EV and ICE.
ICE ON/Start = EV “Ready”
ICE ACC = EV “Idle” (except EV’s have more charge functions in this mode than, obviously, an ICE)
ICE OFF/Lock = EV “Standby” or “Sleep”
Don’t sell yourself short, David. I’m sure you have at least two. Maybe three. And it’s hard to be a romantic (about people or Jeeps or any other objets de désir upon which you many gaze) with more than that.
Did you experience any romance in the car after the date?
wildly inappropriate.
Hyundai spots humans approaching.
Hyundai hypnotizes with control beam.
With humans in passive trance, Hyundai scans pockets and backpacks.
Hyundai does not find any USB cables.
Human subjects deemed non-threatening.
May proceed.
KONA-209 online.
Odd that they’d use a green light as a warning that charging is occurring. Amber or red makes more sense.
Or orange — the color of the shieldings on the high-voltage system.
Good point!
I mean, it’s a normal-ish operation for it, isn’t it? Amber or red would make me think there was a problem, but there’s not.
Update….????!?!?!?
Are they steel-toe UGGs?
CrocUGGS
so you had the Lobster Bisque??
https://www.youtube.com/watch?v=av64gOA9nXM
hopefully some yadda yadda yadda desert
Genuine question/musing: I don’t understand why EV’s have 12V batteries. In a hybrid I guess it makes sense – you need to be able to start the engine even when the traction battery is drained. But an EV? Why wouldn’t you feed 12V accessories directly off the DC/DC converter? What advantage is there to having an extra stash of 12V power?
They mention it in the article:
Because HVAC, Nav, Doorlocks, etc need power too.
Batteries act like a big buffer for the 12v system. It can average out the demands on the dc to dc converter
EVs still needed to be started like any other vehicle. Instead of cranking the starter, the 12V battery powers the relay that enables the high voltage battery. The HV battery is disconnected when the car is off both for safety and to prevent charge draining. Thus, the 12V battery also handles all vehicle off electrical loads like the key receiver, lights, etc.
Also, the DC-DC converter is probably more efficient at high loads, so it’s better to cycle between 100% and 0% load and use the battery as a buffer, instead of running at 5% constantly.
I’ve bricked my Kona EV multiple times by draining the 12v — not enough juice to power up the systems that allow the charge port to be popped open or anything. The car then needs to be boosted, just like an ICE car. One the computers are powered, they can establish the connection to the traction battery, and you’re good to go. I was always very confused as to what conditions would allow the 12v to run all the way down – i.e.: why didnt it DC/DC charge every time? Turns out my 12v battery was bad, and was replaced under warranty.
I have the 2019 Kona, and it killed the battery in 2 years. Apparently, the 12v battery is discharged much deeper than would be happening in an ICE car, and the intermittently recharged. The AGM or Lithium batteries tolerate this treatment better.
So it’s not an updated version of the Subaru Leone center-mounted passing lamp after all?
https://japanesenostalgiccar.com/subaru-third-eye-passing-lamp/
Careful. You’re gonna give Torch a semi.
I was reliably told in 11th grade that the green light represented Gatsby’s unending yearning for Daisy and his hope in the magic of the American Dream.
This has to be the correct answer, Old Sport.
And so we beat on, cars against the current, borne back ceaselessly into the shop.
COTRT
I hereby declare that henceforth DT’s unnamed girlfriend will be referred to as Daisy.
I’m for it.
You can tell her it’s a secret codename, known only to the Autopian Illuminati.
The Kia EV6 has an orange light on the top of the dashboard indicating the same thing. It normally seems to pre-empt a 12v battery failure… Hopefully they’ve learned from everyone else having this issue.
I’m in a couple of Kia EV^ & EV9 forums and it seems every other third post is “Why is the orange light on?” or “My 12v battery has failed”…
Thankfully My EV6 has been okay so far – although I’ve probably just cursed it.
The E-Golf I used to have would keep the 12v circuits alive when it was been charged. It had two 12v batteries in the short time I owned it. Which was a crying shame as it was a great car otherwise.
My 12 volt battery died, too. In my i3.
Sometimes adding distilled water to the cells brings them completely back to life.
If not its time for a chainsaw!!
Was it easy to replace, I’ve heard it’s buried deep under other parts under the bonnet? Did you get a LiFePo replacement or the standard OEM battery?
I got a cheap AGM from eBay. Highly recommended from other i3’ers. $115.
Super easy to swap.
Great, thanks for the info. My 2016 i3 is still on its original battery so I’m anticipating having to replace it soon.
My Leaf went through two 12v batteries in the 5 years I owned it and I just had to replace the 12v on my 2021 Model 3. It seems like 12V batteries in EVs don’t last long (or I have just had really bad luck?). Is there a reason 12V batteries in EVs might fail faster than batteries in ICE vehicles?
The batteries are not continuously charged as they would be in an ICE car. The LiFePo referenced above tolerates this behavior better, and my next battery will be that. The deep discharge cycles that the EV subjects it to are killers.
Yes there are a number of reasons that the battery in and EV or Hybrid doesn’t last as long as one in a traditional ICE vehicle.
Many use very low capacity batteries since it really only needs to close the contactor in the HV battery. Meanwhile an engine requires a lot more energy when it is really cold which is when a battery’s output is the weakest so it gets a relatively oversized battery.
Some never fully charge the 12v battery stopping at an 80% SOC for example.
Parasitic draw. That internet connection for the app to check on SOC, precondition the vehicle ect is always on drawing power when the vehicle is off and unfortunately not all charge the 12v while the car is off or shut off the cellular connection when the battery is low.
Ohmmu makes great LiFPO4 batteries.
I’m reluctant to get one not knowing if the charging parameters are the same as lead acid.
Alas they don’t seem to have one for an i3
it’s $479 for an EV6, ouch – they better be good at that price…
Surprisingly my Chevy Volt manufactured in August 2016 still has the original battery. But when they go bad, the car will let you know catastrophically lol
That battery might last two more decades if you don’t abuse it. LiFePO4 is a robust chemistry.
The 12v is an AGM. I’m assuming that’s the one in question.
I was thinking he was referring to the traction pack. For a 12V AGM, that would also be impressive.
I have a 2014 Hyundai Elantra GT, that we bought in 2018 and I believe had the original AGM battery in it. It lasted until 6 months ago. Even if the battery was changed before I bought it(which I don’t think so since a mechanic told me it failed some testing in 2020) that’s still impressive.
Yes the 12V one, it will be 8 years old soon. The cars is always plugged in at night and its on the trunk, I also live in Michigan. I am expecting no more than 10 years and that will be insane to me.
You can try a desulfonator to keep that thing going:
https://www.motortrend.com/how-to/impp-1105-battery-desulfators-fact-fiction/
I think the reason the 12V batteries in hybrids and electric cars fail seemingly so quickly is they really only have to connect a relay in order to get the car to energize. When the battery is incapable of doing this, it’s dead as the proverbial doornail. I know in my C-Max I had to jumpstart it a couple of times in a week, and then after having to jump it every time I wanted to start the car I broke down and got a new battery. Incidentally, the cheapest source was the Ford dealer, who sold the exact same Motorcraft battery as the auto parts stores for $100 less. They were, however, shocked I was going to install it myself.
Yeah the C-Max is an uncommon battery and it does take some weaseling to get them out and in. Just had to replace it in my Daughter’s Energi. I actually lasted just a few days over 5 years. Which reminds me I’m going to have to replace the on in my MIL’s soon too.
I just have a regular Hybrid, and the battery isn’t difficult to change at all.
Hang on to that Volt for as long as you can. If you’re charging at home every night they make for a great car.
My 2017 is also still on the original battery. Tempted to pre-emptively replace it, but I guess it’s not time quite yet. 7 years also doesn’t seem that crazy for an AGM. I replaced the battery in my other car a few months ago, and the label claimed it would last 6 years. The date code was 7 years ago, so well done there. Especially for a car with high parasitic draw that doesn’t get driven super often.