12V battery

For me, the short term solution was to buy the smallest, cheapest battery jumper pack available. Finding and paying an independent service tech will be more expensive, take more time than 20 jump starts with the pack, and not necessarily fix the problem, which may well involve replacing a significant Hyundai subsystem. I got this pack at $85 for its compact size. They have larger cheaper ones with other features added and there's always a flyer online with discount coupons.

Your profile doesn't say where you live. If you were here in California, I'd suggest calling Hyundai assistance every time to jump the car, and be sure to get something in writing from them. Each time, take it in to the dealer afterward. Once you've made four trips to the dealer without a repair, you can file a California Lemon Law demand for them to buy the car back for every penny you paid for it. That should get the attention of someone competent.

Four trips is a presumption, not a hard and fast rule. I've only been in once for this, but after a second trip I'll write to Hyundai as suggested on page 6 of this booklet, and tell them I'm thinking about a Lemon Law complaint if they can't fix it the next time.

If you live elsewhere, see if your state has a lemon law.

 

Oh - if MD in your name means Maryland, the law is pretty much the same there, maybe even better. This page tells what you can do even before qualifying as a lemon. It says to write to the manufacturer, copy the state Consumer Protection Division with a completed complaint form, and then the manufacturer has 30 days to fix the problem.

 

As a contrast other owner's posts have showed that the 12V battery can also charge on every 4-hour wake-up event, presumably based on the BMS's understanding of the 12V battery's state of charge (not likely the voltage). And from our understanding, the other likely purpose of the wakeup is to check the traction battery's isolation resistance and cell voltage difference. It's not clear what happens if those are found to be outside the acceptable range, perhaps a service light illuminates.
You'll note the 20 minute charging period, which is the same as on the older BMS firmware, and that each subsequent event is timed 4 hours after the termination of the previous event. Also note that while providing 14.65 V (approx) to the 12V battery the actual charge current may taper down to a low level after only a few minutes.

 

I have noticed the taper on other days.

 

Thanks for all the suggestions! Yes, I’m in Maryland. I already bought a portable jumper reading some other comments here. I’ll definitely look into the consumer protection complain if this happens again.

 

In addition to maximum number of repair attempts, there is also a 30 day limit on the maximum total number of days spent in service. This is why I always advise people to leave their cars at the dealer when requesting warranty service rather than continuing to drive with a problem. This starts the clock ticking on any potential lemon-law claims and puts more pressure on the manufacturer to complete repairs in a timely manner. 30 days spent at dealer is not a lot if you happen to end up with a car that needs gearbox, motor, and battery service.

 

The 12 volt system heartbeat seems to have paused.

On 11 Sep 2020, after using the vehicle for shopping (between 1130 and 1330), I swapped out the headlamps for LED units (between 1400 and 1530). The top-up event at 2000 is the dark sky test drive with the new LED units:



Since 2000 on 11 Sep 2020, the car has not been disturbed:





No heartbeat...the system says all is well:



Does the car's 12 volt heartbeat simply hibernate if left alone? Thanks.

 

Thanks for this background.

I suspect a 2.5 day idle period will be scarce in our household

 

Since the car is still very new to me, I figure I would post more 12 volt data here for comment/discussion.

To continue with where I left off (0129 EDT, 11 Sep 2020 was the last time the battery saw 13 standing volts):

12 Sep 2020, a normal looking drop from 13 volts:



13 Sep 2020 (no drives, doors open for quick vacuuming, etc):



14 Sep 2020 (a 25 km times two grocery run):



15 Sep 2020 (car had doors opened and closed numerous times during ceramic application...interior lamp switch was turned off):



And so far, today (back hatch was opened at around 1220 to survey the spare tire well):



The snapshot from "now":



So my initial question is, at what standing voltage will the Kona software push a float charge to the 12 volt battery? Thanks.

 

By contrast and somewhat ironically, on the original BMS software (with Aux battery Saver 'on') I've rarely (if ever) seen a 24 hour period pass without a aux charge initiated by one means or another.

Although it may seem intuitive, there's no indication that voltage is the parameter by which the Kona's system decides to charge the aux battery. Certainly if load and time conditions are controlled, voltage of a lead-acid battery does give a very good indication of SoC and that's perhaps why the BM2 attempts to do this on the display, keeping in mind that it is a generally-applicable tool. But here the Kona's system has little option but to significantly load the battery to reach the point where it can start to assess the situation. I don't think anyone has yet established the facts regarding what algorithm is used, but we do know there is an IBS (intelligent battery sensor) installed and one owner has even graphed (but not interpreted) the outputted data stream.

I'm leaning towards the opinion (a guess really) that the IBS operates full time logging current and voltage data. That's based on (a) it's entirely possible with today's technology, (b) it makes sense, and (c) the IBS is clearly powered 24/7.

Checking power draw to the IBS might contribute to this theory. When the Kona is powered up the IBS data could be downloaded and the auxSoC determined by coulomb counting, similar to how the traction battery is assessed.

An interesting test would be to disconnect the IBS at the positive terminal (intended to attempt to clear its logs) and see if that affects the ongoing charging regime.

 

And as luck would have it, 80 minutes after my last screen shot on post #271, I saw the little LED inside the front grille Hyundai logo light up...sure enough, the 12 volt battery was being fed 14.75 volts.

The battery is now sitting at 12.97 volts...

 

...and the heartbeat has returned...

 

Cheers.

I figure, more data (without being swamped) for the community to chew on, the better for everyone.

 

The AC charge at 14:45 seems to have woken it up and reset the schedule. Then the charge at 19:00 is 30 min rather than the normal 20 min, bringing the standby voltage into what appears to me to be the fully-charged range.

 

I measured my battery current after a hour I open/closed door is around 160ma. Maintenance manual says should be around 50ma. I assume my car’ S battery current may drop to 50ma after a few hours no any operation but I don’t want wait. I think 160ma is low enough. The battery is 45ah can support this current around 280hrs and battery saver system will charge it way before it dies. I also tested battery discharge by put inverter on with 100w load for a few hours. The battery voltage gradually dropped to 11.7v the battery saver still not kick in I stopped the test. This confirmed the battery saver system is not monitoring the battery voltage but only starting by timer. This is different from the statement in manual. Manual says if the auxiliary battery level is low the main high voltage battery charges the auxiliary battery. Manual also says you can turn/off Aux Battery Saver system in system setting but I could not find this function in system setting.


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