Aux. Battery Flat unable to operate any electrics.

Main Hyundai Kona Electric chat
Peter S
Posts: 6
Joined: Sat Apr 10, 2021 4:49 pm

Post by Peter S »

Car fob didn't work and wing mirrors didn't response, though fob battery dead so opened door with key but all electrics dead. Car had over 60 % charge when last used yesterday. Looks like main batteries are not charging auxiliary battery. Don't know whether to call Hyundai or try to jump start electrics. Anyone had this problem ??

adrianmsmith
Posts: 3
Joined: Sat Apr 10, 2021 5:59 pm

Post by adrianmsmith »

Is it a hybrid or electric?
if hybrid did you try the charge battery button?
if so and no luck id get them out to it but i might try to charge the battery first for a few hours. if you dont have a charger then get em out to it!!
charging terminal is under the bonnet in the fuse box....
Ade Smith

kona ultimate hybrid 1.6 DCT 2020
Ignite flame
User avatar
KoolKonaEV
Posts: 40
Joined: Mon Oct 26, 2020 1:00 pm

Post by KoolKonaEV »

Hello Peter,
I'm ashamed to say, yes I have :oops: I phoned Hyundai assist and the AA turned up to our home. Exactly the same symptoms as you. The AA man put his booster on it and it came to life. He said to take it for a short run to see all things were OK and leave it switched on for an hour to allow the main battery charge the 12v battery. In his diagnosis, he noticed the dashcam and asked if I leave it plugged in, I said "yes" and this is the culprit :o
There is a device called the Body Control Module, BCM for short. This controls all things powered by the secondary battery, it detects devices still plugged in even though the car is switched off! It stays activated and hence the battery goes flat, probably because I've hardly done any miles due to Covid and having to 'Stay Local', it's just been sitting on the drive won't have helped. Also, it's not a good idea to wire things directly to the battery, like the hard wire kit for dash cams, for the self same reason. So the moral of the story, is unplug your dash cams if your leaving the car for awhile.
Kona Electric Premium 64Kwh
Ceramic Blue
Peter S
Posts: 6
Joined: Sat Apr 10, 2021 4:49 pm

Post by Peter S »

Thanks for replies.
The only device I have plugged in a speed checker/ radar detector which is in the cig lighter type connection which goes off when the car is turned off. I think the battery is US but its only just over a year old !!!!
User avatar
KoolKonaEV
Posts: 40
Joined: Mon Oct 26, 2020 1:00 pm

Post by KoolKonaEV »

Hi Peter, that'll be the culprit :!: Even though the car is switched off and your radar detector goes off, the BCM 'sees' something plugged in the 12v socket and stays 'live' It's to do with the addresses of each electric item including the 12v socket, it's just the same as my dashcam, it went off when I switched off the car, it was the AA technician that it explained it to me. He recommended I buy one of the new smart chargers that are common place now, just in case it happens again! :roll: He showed me the AA one, but recommended I buy it online rather from him as it is cheaper. I suggest you unplug your radar detector when you leave the car, it's a hard habit to get into as I can confirm :?
Kona Electric Premium 64Kwh
Ceramic Blue
peterb139
Posts: 2
Joined: Wed Apr 14, 2021 1:59 pm

Post by peterb139 »

Just had exactly the same problem, but the car has been used regularly and had a long run yesterday. I have tried to charge the battery but the horn keeps going off
DavidEveritt
Posts: 4
Joined: Mon Oct 25, 2021 5:34 pm

Post by DavidEveritt »

3rd time this year. Thought it was me leaving the hatch open by mistake and the boot light on. Finally found the error this morning.
The 12v battery itself. 5.7v charged to 12.3 after 20 minutes of car "on" on my drive.
Only 1amp charge rate. AA confirmed battery high internal resistance and their Bosch battery cost me £116 on a 2yr old EV.
Dealer wanted a lot more and extra diagnosis time without a vehicle.
Keep an eye open for the yellow light in your Hyundai badge. If you see it on regularly suspect something is not quite right. Mine was on every time I finished at work. More obvious now the dark nights are with us
Kona-MG-Newbie-EV
Posts: 2
Joined: Wed Dec 15, 2021 12:51 pm

Post by Kona-MG-Newbie-EV »

Hi all. I am a new EV owner. Picked up my new Kona EV in the middle of November 2021
Yesterday I had a Pod Point installed and was so excited not to have to use a Granny Charger. I charged my Kona and then went out for a drive - about 40 miles.
Got home with 70% charge remaining. No warning lights or anything like that. Switched off my Kona went to bed.
This morning I woke up to find a dead Kona.
As the key fob was not unlocking the doors - I wondered if the 12v battery could be dead.
I called Hyundai Roadside Assistance and an AA man was despatched. He arrived pretty quickly and thoroughly checked everything. The battery was down to 3 volts. It took a charge, but Mr AA suggested taking the car to the dealers to get the battery replaced as the 12v battery failed the testing.
My dealers could only fix this on 30 December - which is as much use as an ash tray on a bicycle!! Neither could they offer me a courtesy car.

So it seems the 12v battery in my Kona is poor quality - I do hope this is not going to be a running story. Anyone else had the same problem ?
Premium Kona Electric - Galactic Grey - Smaller battery - My first EV - Bought Mid November 2021
Mark Grosvenor
Kona-MG-Newbie-EV
Posts: 2
Joined: Wed Dec 15, 2021 12:51 pm

Post by Kona-MG-Newbie-EV »

DavidEveritt wrote: Mon Nov 15, 2021 8:42 pm 3rd time this year. Thought it was me leaving the hatch open by mistake and the boot light on. Finally found the error this morning.
The 12v battery itself. 5.7v charged to 12.3 after 20 minutes of car "on" on my drive.
Only 1amp charge rate. AA confirmed battery high internal resistance and their Bosch battery cost me £116 on a 2yr old EV.
Dealer wanted a lot more and extra diagnosis time without a vehicle.
Keep an eye open for the yellow light in your Hyundai badge. If you see it on regularly suspect something is not quite right. Mine was on every time I finished at work. More obvious now the dark nights are with us
Thanks for your post David - Great advice!
Premium Kona Electric - Galactic Grey - Smaller battery - My first EV - Bought Mid November 2021
Mark Grosvenor
frainy
Posts: 2
Joined: Wed Mar 30, 2022 5:04 pm

Post by frainy »

My brand new Kona Electric was unresponsive after charging overnight. The AA guy used his battery charger and it sprang to lfe. Apparently I had left the car unlocked so the car was not fully shut down and somehow or other this drained the aux battery. Sounds a bit odd to me.
Post Reply

  • You may also be interested in...
    Replies
    Views
    Last post