If you've had a dead 12v battery please respond

Linda, my 12V battery was dead at the time Hyundai arranged for me to pick up the car, brand new. It hasn't happened since then (~3200 km) but it certainly was irritating.

I wonder how Hyundai ship the vehicle across the Pacific? I.e. what state of charge in the traction and auxiliary battery? Would you disconnect the auxiliary battery during the voyage?

 

Read the Dead Kona EV thread. Could be the same thing.*I see you did.

 

Electriceddy

When you say "... leaving my car in run mode to recharge the accessory battery..."

What do you call run mode? Is that the driving mode? Or is it the accessory mode that we trigger by pressing the power button without having our foot on break pedal?

I think you mean the latter as I am guessing that idea is to deplete the battery a little bit, but just want to make sure I didn't get this wrong.

 

Could you describe the differences between your run mode VS utility mode, in terms of 12V battery charging behavior and otherwise?

Sent from my ONEPLUS A5000 using Tapatalk

 

I had this happen once; for a few days beforehand, I noticed that BlueLink was unable to get service, and the cellular modem reported its IMEI as all zeroes; I figured rebooting the car would resolve it, but normal restarts didn't. I was about to make a service appointment when the battery died overnight; a jump revived it, and conveniently fully rebooted the system such that the modem reported a real IMEI and was able to connect. It's purely speculation, but I'm slightly suspicious the battery was run down by the car attempting to find cell service; certainly that's one of the quickest ways to run down a phone battery, and while I'd be a bit surprised it would actually manage to drain the car battery, it seems plausible at least.

 

This sounds like the problem I experienced and discussed in "the other thread". Although, I can still only speculate since I do not have proof of the cellular connection not working. I only have the errors that were being shown on the web site and smartphone interfaces. Where do you find the IMEI information? Also, do you consider turning the car on and off 'Rebooting' or is there a way to truly reboot it other than disconnecting the 12v battery for a few seconds?

 

You can find the IMEI info under All Menus > Setup (on the second page) > Blue Link > Modem Information on the infotainment system. In my case the signal indicator in the top right also showed no bars/an X while it was out of commission. I had hoped turning the car on and off would reboot it, but it didn't; other than having the battery die I don't know of a way to do it (although disconnecting the battery does seem likely to work).

I could be completely off base with this, but it's the only thing short of a random bug or hardware fault I could think of that would at least somewhat make sense. Will definitely be interesting to hear if this echoes others' experiences as well!

 

When the car is turned off, it draws substantial current ( several amps) from 12V, gradually decreasing over several minutes. Although a modem trying to talk wouldn't draw much power, it may be be in the critical path of the shutdown process. The current drawn shortly after poweroff would certainly be enough to drain the battery in day or so. However I think it is probably more subtle than simply not being able to communicate, as people will surely have parked in underground car parks etc. and more would have had this issue.

 

You would think that there would be a battery management system in place that would charge the 12-Volt battery from the main battery on demand when it reaches a certain depletion level.

 

There is. Sometimes it doesn't seem to work.

 

It's unclear if that "engineering mode" telematics setting has any
real effect. There's only one way to be sure.

In my observation it takes 15-20 minutes for enough stuff to go to
sleep and settle down to a total draw of under 20 mA. I don't know
if lack of the cell modem affects that time.

_H*