Dead 12V battery in 2019 Niro EV

Is the battery a 'deep discharge' type or regular? When we replaced the battery in our Prius it was quite a bit more expensive than a regular car battey, but I checked and Hybrids, and I suspect EVs, require batteries which can be discharged to a relatively low level, which requires a better quality of battery. A regular battery would fit but are not going to work for a while.

 

This is a very interesting discussion, particularly for an ICE driver who hasn't yet bit the BEV bullet.

From the outside looking in, I would mention that ICE cranking batteries supply power to NOTHING once the ICE is running - the alternator/charging circuit is using engine power to run all the electrics. This makes the BEV 12V battery seem like a totally different application. I say "seem" because we are missing a critical piece of data. We are missing a detailed understanding of how the BEV primary drive battery and DC-DC convertor recharge the 12V battery.

Without understanding how the 12V battery is kept charged through all operating regimes we're kind of flailing around in the dark.

This having been said, I live in a northern climate (national capital of Canada) where we get real winters. I have many years of ICE operation and, in particular, a lot of experience with a fleet of Honda vehicles (Civics, mostly Accords, CRVs). We have an unwritten rule in our household. NO Honda battery will survive its seventh winter. They will, almost without exception, live through six winters. They will, almost without exception, die on the first really cold day of the seventh winter. This data comes from 40 years and several million kilometers of experience.

Why would the Kia Nero EV battery only last 3 years? This behavior leads me to believe this battery is either cr@p from the outset or that Kia has really messed up their logic around maintaining charge on the battery. Now I'm really curious to know how they charge the 12V battery!

 

I had a jump start situation back in the depths of not going anywhere (Covid, if you recall)...yep, a battery pack jumpstart works...at least it did for me on a 2019 Niro EV. In terms of 12 volts, sometimes you get more than more than 3 years, sometimes not. I had a Ridgeline where Honda had to replace the 12 volt under warranty because it just wouldn't hold a charge. 12 volt batteries are the most common point of failure in all vehicles, ICE, PHEV, or BEV...well, other than 'the nut behind the wheel'

 

Why? Bad luck...I had a Ridgeline with a battery that died within a year or 18 months...Since my initial jumpstart issue (previous post) and a software update to the Kia, I have had no issues or problems with the battery. BTW: the Niro EV does OK in the snow, though the Puget Sound area isn't quite as snowy as Ottawa. If it's really snowy next winter (might be another La Nina), I rely on my 2nd EV, Rivian R1T. Rivian R1T Snow Performance: Testing Various Drive Modes (insideevs.com) Rivian R1T on a Snowy Road Is Like a Fish in the Water, Better Than a Tacoma, Claims Owner - autoevolution

 

the 12 volt battery in my 2011 Leaf lasted about 3 years. Put in a top of the line Canadian Tire battery and its still good
in 2022. I think its built into Asian made batteries

 

Perhaps a different angle on the dead 12v battery issues ...
I've had the recharge mode on ever since getting my 2019 Kia Niro EV. So I have occasionally looked out and have seen the green light indicating 12v recharge underway. The other day I started out with ~240 of indicated range. I made a 90 round trip that day. The next day, rather than seeing an expected ~150 range, I had 80. This is the only time I have seen this kind of drop. (No, it was neither very hot or cold overnight.) Relative to this thread, I am wondering if the 12v might be (suddenly and dramatically) failing after 3.5 years, and so the car spent the evening working to recharge it, thereby using up a LOT of range??? The problem with this theory, it that the failure would have to be precipitous (since no previous symptoms) and episodic, since the next night, there was no repeated, dramatic loss of range while the car sat.
Thoughts?

 

Sounds like a good possibility...12 volts just go sometimes...there are ways of testing a battery, most involve a battery tester/multimeter, but rule of thumb is that lots of batteries die after 3-4 years, not all but lots, so not unexpected. I'm waiting for the one in my 2019 to go. Even though it's an EV, I keep a usb jump start unit in the car just in case I can't start it because of the 12 volt. This is the one I have via Amazon:
NEXPOW Car Jump Starter, 21800mAh 12V Portable Car Battery Starter, Auto Battery Booster, Lithium Jump Box with LED Light/USB Quick Charge 3.0

 

My 2022 Niro EV died when I stopped for 5 mins at a highway rest area. When I tried to start it, the startup routine ran, and then said "Critical Battery Issue. Call Kia Roadside Assistance and tow to nearest dealer". I thought this meant the main battery pack had a fault (if it was the 12v battery, it wouldn't run the startup routine, would it?) Anyway, after towing it to nearest dealer (who was swamped and couldn't even run diagnostics - letting it sit on their lot for 3 weeks), I towed it to another dealer, who told me they couldn't even unlock the car with keyfob. Eventually they determined 12v battery had discharged, and after charging it, they said it works with no errors. Is it possible this was all just a 12v battery problem?

 

Stranger things have happened...I have gotten 'ghost codes' on both my EVs from time to time. Sometimes turning off, then on solves it. My Rivian gives me the option of two different types of reboots if letting the car 'sleep' for a few minutes doesn't solve it. BTW: having a number to call where you can talk to a tech that is specific to the EV is really nice. My Kia dealer has one tech that they have designated for EV's...had an AC issue this summer, not EV specific, but they wouldn't schedule me with anyone else, so had to wait.

 

Thanks for all the info everyone. I have a 2019 Niro EV and the 12V auxiliary battery died on Super Bowl Sunday and then again twice more in April. One time my wife had left the hazard lights on for a few minutes while unloading the car. The final time it may have been the headlights after the car was off, but in all the cases, it didn't take much to drain the 12V battery. The second time we got it jumped by AAA and the tech said that since it was almost 4 years old the battery was at the end of its useful life so we bought a Gooloo 2000 Amp Battery Jump Starter and it came in handy a few weeks later. Those things are really easy-to-use versatile gadgets and great timesavers.

After reading this forum and looking online for a replacement battery I realized how difficult it was to find proper information on what to get. This forum was probably the most helpful as the Niro owners manual is very lacking in information. It really doesn't tell you anything about the auxiliary battery and replacement info. My OEM battery was the Rocket battery CMF45L-DIN, manufactured in Korea by SE Bang. The battery group size is 99R, or T4. Group sizes 140R or H4 are apparently also similar battery sizes and may fit, but do verify that on your own.

After looking at the limited choices online, I settled on a Ford Motorcraft BXT-99RT4-A battery for $152 plus tax (bought through my local Ford dealer). This 470-amp Motorcraft battery has as good as or better specs than more expensive models from Interstate, Napa, Duralast, etc. and came with a 3-year warranty, so I thought I'd give it a try. It is just a little bit shorter than the OEM, but it fit in perfectly and started right up. I thought I'd have to reset all my radio stations after changing the battery but those were saved. Time will tell if it's a good battery. Here's some photos of the two batteries side by side and the Motorcraft replacement installed in our Niro.

 

A Group 26R battery seems to fit and work fine in my '22 Niro EV. Easily available. And it can be pretty inexpensive. Check Walmart for prices.