Dead Kona EV!

Huzzah! I'm having a very similar problem (12v battery has died four times in the last 3 months). The dealer serviced it in July and said the 12v battery was healthy but they applied an ECU upgrade (901.OS EV Battery Logic Improvement (BMS) - photo attached ) . But the 12v died again. I don't think my dealership has sufficient experience to know what to do. I will pass your post info on to them, but if necessary, could they call your dealer in SF area and talk with Pradep?

 

Not wanting to be unhelpful, but your dealership ought to know what module Pradep was referring to, and if not, it sounds like @electriceddy does. LMK if you still need help after another talk with the dealer.

Is there any way to tell if it's the BCM, short of replacing it? If the car is under warranty, HMA requires more evidence than a criminal jury; if not, it's an expense on spec.

And your images require a login to view.[/QUOTE]

 

I see only the broken-image icon for the two images.

 

When I see these I just right click and copy the image in a new tab, and then it shows up.

 

And I get this:

 

From RUN mode select Utility mode. That will ensure that it holds the charge level for the duration.

Is the port area and charger plug clean, regarding electrical connections?

 

RUN mode is a bit sporadic at offering a charge-level voltage to the 12V battery in my experience, while Utility mode guarantees it.

 

I've been running with a LiFePO4 12v 40AH for the last 3 years without issues. My factory 12v did't last long (a little over 1 year). It was replaced under warranty, but I benched it and ended up putting it the ZOE which also died about 3 years in. Charge to the battery is generally applied while car is running in Drive mode, Utility mode, any time the main battery is charging and during any battery maintenance the car may be doing based on your model and software versions.

The best thing about the LiFePO4 for me is that
1) Charging profiles are compatible with the Lead Acid and charging system
2) A full discharge (should it happen) doesn't stress the battery like Lead Acid
3) Cycle life even at 100% DOD is many thousands
4) Prices are approaching parity with lead acid
5) More of the current generated for charging the 12v is actually stored in the 12v battery as opposed to lead acid (lower losses)
6) The battery is less than half the weight
7) Temps in the engine bay do not get warm enough to affect performance of the battery

I'm sure many people would be against it or perhaps mildly dubious about using one, however if mine was to die I'd buy another. When the ZOE's lead acid battery dies, it'll be getting a LiFePO4 repalcement for sure!

I've purposely flattened mine as a test and the BMS turns it off, it also has a manual switch, and with mine, once the battery lies flat for about 10 minutes, if I switch the battery off and then on, there's enough (I presume surface charge/voltage ) to restart the car, however I do carry a lithium jumper just in case also (It's never been used)

 

Tesla moved to a small 16V LiFePO4 a couple of years ago as you're no-doubt aware, but the intent appears to be better system management, not increased capacity.

Their aux batteries internal BMS can communicate over LIN with the car to request an immediate charge rather than having to wait for a timed event as the Kona does. Apparently when the driving cameras are in 'parking' mode it's 'on' all the time. Ironically the Kona's battery sensor (on negative terminal) should be able to do this as well provided the car was 'listening' and Hyundai had anticipated the usefulness.

I've never had an issue with my Kona's OEM Rocket battery and see no reason to stir anything up past the replacement issue I've documented elsewhere. But what mostly puts me off the Ohmic brand of these aftermarket LFEs is Ingineerix's views on YouTube, noting that some comments are specific to its use in a Tesla.

 

Based on your description it sounds like it may have a defect. Even an abused battery can do more than that.