12V battery

I don't think they killed my battery; I'm pretty sure someone left a dome light on for the weekend. I'm aware other EVs share this Achilles' heel ,but I'm still annoyed by fact that we have a 400 V battery with 67 kWh of energy in it and can't seem to get a 12 V battery with <1 kWh to stay at a reasonable state-of-charge. :|

Not all EVs have 12V battery issues. The Chevy Bolt EV I sometimes drive has 3+ years on the original AGM 12V battery (manufacture date in 2016) and never had any issues. My eNiro 12V battery died in less than a year with similar usage. It's the same simplistic system as the Kona. It works okay for simply "maintaining" a parked car and compensating for typical resting battery drain. It does not cope well with any unexpected additional drain or 12V battery with degraded performance.

Never tried leaving the dome light on with the manual override switch. It does turn off everything automatically if you leave door or hood open.

Utility mode overrides all the automatic shutdowns for obvious reasons.
 
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I recently had the Kona refuse to start after a weekend camping trip, claiming I did not have the key in the car. I was worried about the key battery being dead, but the OTHER KEY did the same thing. I tried using the contact feature of the key. Didn't start either, although it lit up part of the dashboard. Then it would chime and turn off again.
If the 12v battery is on the low side, even though usable, the remote key sensor does not work reliably. In that situation, I've had problems unlocking the door with the key in my pocket. The giveaway is that both keys fail.
 
Newbie here, my wife is taking delivery of a Kona EV (2021) this Thursday.

I'm aware of the EV 12 volt battery challenges and see that the length of this thread is telling me the Kona is similar.

On my other thread, I posted these questions:

I'm slogging thru the owners manuals page by page.

Back to my 12 volt battery observations: there are two operator options that deal with the 12 volt battery health IMO.

The first option is to allow the high voltage battery to automatically top up the 12 volt battery when the car is shut down...this is the same technique that is hard wired into the TM3. Are folks with 12 volt battery issues not using this option?

The second option seems to allow the traction battery to provide power to ancillary 12 volt items while the car is not "on", but it sounds like one has to employ this option every single time one wants it...am I interpreting that one correctly...or can it also be set to always have the high voltage battery always run the 12 volt accessories even when the car is not "on"?

Thanks in advance. Cheers.
 
Newbie here, my wife is taking delivery of a Kona EV (2021) this Thursday.

I'm aware of the EV 12 volt battery challenges and see that the length of this thread is telling me the Kona is similar.

On my other thread, I posted these questions:



Thanks in advance. Cheers.
Used to be an option before the software update (campaign 960) , but they took the "aux battery saver +" so now it gets charged when the car has been powered off but more frequently than pre-update
Note : you can still leave the car powered on occasionally(or utility mode) for a manual top off when you decide that may be beneficial.
 
View attachment 8933 View attachment 8934 View attachment 8935 I have not had any 12V battery problems on my 6 months old car but I am not taking any chances. I have just installed DIY a retro-look voltmeter on my dashboard so that I could monitor both the resting or charging voltage with a quick glance. It also serves to add a custom look to an otherwise bare looking dash top.

Does this offer any advantages over the meter I've got plugged into the 12v socket? Resting voltage can be checked by turning on accessory mode.
 
The meter you talk about, do you have a link to the specific unit you use? Thanks.

I'm afraid I can't be very helpful. These were discussed in another thread long ago, and there are many brands. Mine includes a thermometer, of limited usefulness in the lower bin. I recommend the one with the coolest lighting. :cool:
 
The advantage of the BM2 Battery Monitor bluetooth voltmeter is that you do not have to disturb the car to take a reading and it logs every 2 seconds 24/7. In this example just opening the door takes the voltage down 0.4 V. Pressing 'on' without the brake pedal sends it down another couple of tenths to about 12.3. Pressing 'on' with the brake pedal (Run mode, which powers up the LDC) brings it up to charging voltage, 14.65 approx. Switching 'off' and closing the door results in a partial recovery.
All I need do is get within 10m of the car and check it with my smartphone which displays the voltage with 1 sec sampling intervals. But normally I only check the history every few days to make sure the level is being maintained. It draws less than 3 mA.

959CC8E2-9751-470D-80A4-F2C4C7DD618C_1_201_a.webp
 
The advantage of the BM2 Battery Monitor bluetooth voltmeter is that you do not have to disturb the car to take a reading and it logs every 2 seconds 24/7. In this example just opening the door takes the voltage down 0.4 V. Pressing 'on' without the brake pedal sends it down another couple of tenths to about 12.3. Pressing 'on' with the brake pedal (Run mode, which powers up the LDC) brings it up to charging voltage, 14.65 approx. Switching 'off' and closing the door results in a partial recovery.
All I need do is get within 10m of the car and check it with my smartphone which displays the voltage with 1 sec sampling intervals. But normally I only check the history every few days to make sure the level is being maintained. It draws less than 3 mA.

View attachment 8989
Definitely sets the standard for monitoring with accurate readings and a with a minimal impact on access load of the 12V system.
What ever system or devices used, I guess the main objective is to realize Kona Electric has a really small capacity accessory battery and to take appropriate action to try to keep it as minimal an issue as possible.
Short and frequent drive patterns (as most of my drives are) equal less charging, and for those who drive longer distances the benefit being leaving a higher SOC .
 
Just be aware, if you're trying to monitor 12v battery failures, that the BM2 has no nonvolatile memory. So if the voltage drops way down (maybe in the 6 - 9 volt range) it will lose everything you haven't downloaded into the app and there will be no record of that failure. And the app doesn't suck the data automatically; nothing transfers until you display a graph.
 
Well I got the call today after nearly a week at the dealers that my Kona's 12v battery was replaced in context to recent no start condition that I experienced 2 days after my traction motor replacement. Basically the car would tell me to put my foot on the brake to start every time I tried to do so without actual start. Went down, thanked my service advisor and I headed to a shop literally 5 minutes away, stopped briefly and the car would not start again, giving me the "foot on brake to start" message. I used my booster pack and it started, drove to dealer, turned if off and tried starting with no joy. Sadly I reclaimed the loaner Accent as it seems the Kona will be in the shop a few more days. I gotta wonder if the DC to DC converter is not functioning properly. It might be coincidental to motor swap or I suppose it could just be a loose connection, that or its always been a problem and that is why my old 8 month old 12v battery gave up the ghost. I tried to talk to the tech but he was too busy for me. Probably just as well, as they always look at me like I'm crazy when I suggest something diagnostic. Oh well, at least I have a loaner.
Thought I would update my saga. Got the car back today. Tech was able to replicate the no start situation(thank goodness), basically reconnected and contact cleaned all engine swap related connections. This seemed to resolve the problem. He is calling it a non specific loose connection problem. Hopefully this does it.
 
Two months since I got the service campaign, and nothing interesting happened until this week.

And this week, what happened is that nothing happened. There have been no charging events since Aug. 24, when I drove a short distance around 13:00, came home, and didn't plug in. After the drive, the voltage settled in around 12.6 - 12.65, as best I can judge from the graph:

12v discharge 8-24.webp

The next day there was this blip:

12v discharge 8-25.webp

Since then a flat line, with a few jiggles like at the right of the graph above. The voltage right now is 12.53v. Shouldn't it have drawn down more than that just from whatever it does with itself?

I'll try not to do anything to the car and see what happens - or doesn't.
 
So, how many days did the Kona sit idle before the short drive on the 24th? Presumably that's all in your BM-2 history.
 
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