If you've had a dead 12v battery please respond

And it probably only gets enabled once teh car is in sleep mode - the issue looks like the car not going into sleep mode

 

Thanks for everyone who's keeping this thread short. It's helpful to have this poll and list of failures without having to read a lot of discussion.

I've had a dead battery several times on my three month old Kona EV, and documented it pretty thoroughly. In my case, the car is refusing to run the Auto Battery Saver function when plugged into an EVSE, and on a few occasions it did that in a way that drained the 12v battery. There's a graph here and a video a few posts down.

After the first time, when Hyundai sent the AAA to "jump start" it, I bought a $70 lithium battery jumper pack and now consider it a minor inconvenience. Once all this virus stuff is under control, I'll see if the dealer can get it fixed, but it's not worth driving an hour to the dealer, leaving the car, getting a rental, etc., when I know I can jump it in two minutes. Meanwhile, I leave it unplugged unless I need to charge.

 

Your poll fails to reflect another option: "my battery was dead and it was the car's fault". It's what happened to me. Hybrid Control Unit replaced under warranty 8 months after purchase. Off the road for 1 month. It's been fine since. Knock wood.

 

Just found this poll. That's a large percentage of respondents experiencing a dead 12V battery!

I am on 4th 12V battery. I call the dealer and say 'I need another one' and they call when it's in. All under warranty.

On Friday, I get the 356V battery replaced and they said new firmware may solve the 12V problem. Fingers crossed.

 

Don't count on it. Mine got worse after the traction battery was replaced. Although, it is possible that the 12v battery had degraded so severely that the timing could be coincidence. Either way it was a frustrating few months.

 

A higher percentage of those with the problem will respond. But still.

Please post the firmware upgrade number(s) from your service order.

My 2021 was built in late 2020, but the service advisor says there are no updates outstanding. I can't believe that.

Anyone know if there is a U.S. equivalent, or is it the same?

 

Happened once, after a very cold night, while it was charging (L2). Jumped it, and then it was fine. No other problems in 2 years.

I'm not sure if we had a door open, perhaps? Hasn't happened in the 2 months since, so I'm not worrying about it.

One thing I noticed is that unlike an ICE car, while can be disconnected from the jump pack as soon as the engine is started, I needed to leave the jump pack attached to the battery longer, until the car had a chance to charge the 12v battery from the traction battery. I'm not sure how long it took, but I left it hooked up for an hour, while "running".

 

Had to get jumped for a dead 12v yesterday. Every light was blinking, ABS triggering when I touched break trying to start it, beeps and clicking noises all over the damn place.

How ling till I can expect it to crap out again?

 

How long is a piece of string? Lead acid 12V batteries don't like being discharged to that extent, and when it happens there is usually a penalty in terms of performance and battery life. One such event is surviveable but each subsequent event will take a toll. If this is the first time you'll probably be ok, but it would be a good idea to get a small lithium jumper pack which will get you going if it happens again.

 

Hard to say when it will happen again, just expect it to happen more often and it will get progressively worse each time it happens.

 

Wow 4 batteries, that is impressive. I have been on battery # 2 now for almost 20 months. The new charging regime seems helpful. I am not expecting 5 years for EV service but 3 years would be nice.
Weird that Hyundai is obviously still having issues with dying batteries in the new Ioniq 5.

 

It happened to me twice. Had to pay for replacement on both occasions as it was over 2 years / the specific km.

 

My car started dying, about once or twice a week. on 2nd visit to dealer, they hooked it up to some machine that tested it over night....they said battery tested OK....I said it's not....turns out, their over night battery/drain tester was defective. They installed new battery and problem solved. Car 2019 Ultimate, battery was about 2 yrs old.........no charge/proration for new battery

 

On 2019 Kona EV bought new on Dec 31 2020 -- Three times the 12v battery has gone "dead", and jumping re-started it. After my friend with his 2019 Kona EV called me to jump his dead 12v battery, we went to NAPA and both bought small Vector 800a lithium jump starter (& USB powerbank) units, and have both used them to jump our Konas since. Oct 25 2021 I got a new 12v Interstate 26R battery at the Hyundai dealer under warranty (which the dealer just slapped a Hyundai sticker on the side of) at 7321 miles.
WINTER STORAGE: Have stored Kona from Nov 23 2021 to present in unheated & unelectrified garage, disconnecting 12v negative cable (against advice to remove battery to inside storage) and with driving battery at 82%. Hyundai dealer and manual (p. 7-22) recommended inside storage of 12v battery and charging driving battery to 100% (p. H-5), but I only charged big battery to just over 80% since that was the advice re:fire hazard until replacement battery is installed. In 4 months of storage at winter temperatures (Ithaca, NY), new 12v battery with no trickle charge has degraded to 12.20v from 12.70v but big battery is still at 81%. Just got word from dealer that my big battery is scheduled to be replaced in a couple weeks.

 

That's useful info for cold storage since the question comes up often.
As an aside I lived in Ithaca for four years in the mid-1960s so I have a rough memory of the cold. My dad was in Cornell's astronomy department.

 

Are the problem 12v batteries lead (Pb) or a calcium/lead acid? The reason I ask is the 1980 GM cars came with the calcium/lead and they would not work in cold Canadian weather. They ALL had to be changed to lead to get them to start in winter.

I have lead (Pb) as my 12v battery in my 2022 Kona electric so at least it will work in cold Canadian winters.