[hbapostbox]

Have read a few threads in this forum on the 12volt battery. This is a real issue.

We had had this issue a few times, with the doors open for not very long - maybe 15 minutes. At the 2 year service we asked for the battery to be checked and were told it was fine.

Now stranded again, after doors open for five minutes to load the car. Ridiculous. And it is a Saturday, so Hyundai service is closed.

seriously frustrated that the battery was not changed at the 2 year service!!!!!
Wondering whether to find a different type of 12 volt battery!

 

[embdenb]

This is not normal. Either the battery or charging system is not working as it should. You should not need an upgraded battery. If under warranty, take it to a different dealer. If out of warranty you could try AutoZone ( or any other similar reseller) and have then test the battery by applying a load to the battery.

 

[Kiwi]

There is nothing different here than any other Kona EV. You can get away with 20 minutes if your 12V battery is in top condition. Using a different 12V battery is not going to help.

For whatever reason the car wakes up to a level where it expects you to get in and drive. A similar thing can happen if you plug in your home charger when it is not powered-up. The car keeps trying and may drain the battery in desperation.

If you want to leave the doors open simply place the car from Run to Utility mode using the dash menus and you can leave them open all day. It cannot be driven in or from that mode without having the key present and starting from "off".

 

[ELPTXJC]

Interesting that the main battery doesn't kick in, like on Teslas. If I left doors open (like when cleaning it, or something), the main battery was active until in about 15 minutes, it killed everything (sleep mode). But they had issues not charging the 12V batteries correctly, and having to replace them every 2 years too. So it's always something. Ha ha. But glad to read about the 'utility' trick, since we plan to buy a Hyundai EV after the Kona N. We weren't a fan of the Tesla, but fortunately we tried it for 1-1/2 years for free, since we actually made $3,500 (after all taxes, accessories, and even a 240V outlet installation. Ha ha) when we sold it 2 weeks ago. But it's still too early for EVs now IMO, especially where we live, so will wait a few years for charging infrastructure to catch up, and reliability to be better.

 

[PSP]

I’ve had this flat battery issue 6 times now. Very frustrating. Withiut knowing this forum, it took me 3rd time to think that it was probably due to the boot door open for loading and or doors so always took care. Now I learn it is more than that and a fundamental issue. Why don’t Hyundai admit it and warn customers?

The last time was last weeken having driven to Edinburgh for the weekend , we unloaded and before locking I checked the battery ( I always carry a charger and cable now which yo7 have to have reachable from the driver seat because as you all know, yo7 on,y ge5 access there wit( the emergency key) and it was 100%. Then we went out for the afternoon and dinner , and 6 hours later, I could not open the car! Battery flat! Nextmorning , a Saturday, I callen Hyundai Road assistance who arranged a friendly AA van. He boosted the battery and the car started. (The main battery will fully charge the 12v battery if you leave the car on in Neutral) . He also did a battery health test which took 10 minutes , and said “Replace Battery”. He even arranged for the Edinburgh Hyundai’s garage to squeeze me in to do it. Got there (20 mins drive) and they had it for 10 minutes and said a battery is fine, must be an issue elsewhere with the electronics and I had to make an appointment with my home garage ( Aberdeen). They had looked at it in March and could not find anything wrong with the battery or the electronics..SO THEY DONT SEEM TO KNOW ABOUT THE ISSUE WHICH BY THIS AND OTHER THREADS IS COMMON! They should ah e at least said , don’t leave the doors or boot open more than a few minutes!

what else causes this. What a design fault!

I’ve baught a battery booster to keep with me now instead of the battery charger. Its unclear to me if it is suitable for the Kone battery as the booster is rated for 1500cc cars or smaller. ( how is that relevant) https://www.amazon.co.uk/dp/B00FB7LTO8?psc=1&smid=A3P5ROKL5A1OLE&ref_=chk_typ_imgToDp

Watch this space. I have an appointment on 16th August and demanded a courtesy car so they can keep the car for a week to test it properly.

 

[Kiwi]

... Now I learn it is more than that and a fundamental issue.
...what else causes this. What a design fault!

If it's a fundamental issue I don't have it, but I don't have BlueLink telematics either which makes me wonder if that's a factor. Next month my Kona and 12V battery will be four years old. If you buy and install a BM2 Battery Monitor you can not only keep an eye on it on a daily basis but also have good evidence for a diagnosis.

Leaving the boot ajar is just as bad as leaving it open and in both cases the car refuses to charge the 12V battery for the interim. Be sure you've twisted in the two adjustable rubber boot stops to reduce the risk.