My initial thought is that there is a "vampire" drain on your 12v battery caused by some electrical component not switching off properly when the car is shut down. If you search this forum you will find a number of threads that discuss this problem. It is certainly not normal for the battery saver to activate more than once in 24hrs, though I believe newer models had a software update so that the 12v battery was recharged 4 times in a 24 hour period.

 

Yes, I agree that there could be a vampire drain there. I searched and followed some threads, but I don't find the same symptoms. Regarding that software update you are talking about... ¿Is there any information about which update is the responsible of that change? That statement match my observations.

 

From what I remember the most recent software update increases the aux bat saver timeout period from once every 24 hrs to every 4 hrs. This is to mitigate the dead 12V battery issues that the IONIQs seem to suffer from. Your vehicle is doing exactly what it supposed to do based on the second plot, ie, check and boost the 12V battery every 4 hrs. Not sure I see any vampire drain in the second plot. Everything seems to plateau after 2 hrs.

 

I wonder if your 12V battery is no longer holding its charge very well. My 38 at the moment only does a topup every 24 hours, and these usually last about 20 minutes, just like yours seem to. I don't yet have the latest update to force 6 topups a day, and it's very rare for me to see more than one topup a day. I have auto top-up battery-saver enabled. I have once gone as long as 42 hours without a topup, I think this was a glitch! I expected a topup, and the voltage suggests I ought to have got one.

My 12V is usually between 12.6V & 12.5 volts or a bit below when the topup starts.
If my 12V is at 12.6V, the daily topup then lasts 20 minutes.
If my 12V is at 12,47V, the daily topup lasts 1 hour.
If my 12V is at 12.43V, the daily topup lasts 1 hour 20 minutes.

So it looks like when the topup test is done, the voltage is used to decide how long to topup. M battery has been flattened to 8.4V twice now, and is probably damaged. I've seen a plot from a Kona in good condition, and that sat at almost exactly 13.0V between the 6 topups per day it was doing. So I'd expect a battery in good condition to be at or near 13V between topups, not dropping from 12.9 down to 12.6 like mine does between topups. I suggest yo get a new battery. Yuasa do some I believe, but note that the Delkor that Hyundai fit is a plain lead-acid, NOT an AGM battery! AGMs want a different charging voltage than plain lead-acid I believe.

 

I wonder if your 12V battery is no longer holding its charge very well.

I suspect my 12V is also damaged as after the 20-minute top up it soon falls back to 12.6V or below, and if I wake up the car for any reason it drops to 12.1V only recovering to around 12.4V before the next top up.

I’ll probably get a new battery in the autumn as mine is out of its 2-year warranty now, but the replacement won't be a Delkor battery. I enquired at my recent service about the cost of a replacement 12V battery, to supply and install £180 I was told…

My Ioniq has had the recent update which allows 6 x 12V battery top ups in 24 hours, my BM2 readouts look similar to the ones at the top of this thread.

Since the software update, going through the settings I can’t find the battery saver option? Maybe it’s been removed, or I need to visit Specsavers…

 

change the 12V battery, I got this "No Start" and 12V was empty several times, was in for service and they change it, was an error on it they say, what I do not know

 

Final update: it was not wrong.

As stated by some members of the forum and people around, the car was working properly and that behaviour was due to an update performed by Hyundai.

My case reached Korea, where they said that a BMS update was made which disabled the Battery Saver Option, keeping it locked in ON and topping up the battery frequently. In newer cars, that option is removed at the factory.

If I were the develompent crew or technical service, I would be embarrased. First of all, they remove a function you paid for in order to fix a parasitic drain instead of fixing the real problem. The technical service is not aware of what they do and lack of EV knowledge.