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Discussion Starter · #1 ·
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This was during the shifter recall service.
So what's interesting here is the 12v SOC is very poor. 31% is far too low for lead acid 12v batteries. You are not supposed to discharge them below 50%, and if you actually cycle them this much you get maybe 500 cycles out of them.
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I keep seeing the orange 'recharging' light on even when I have driven the vehicle a while or plugged it in.

I think it is putting a cycle on the 12v battery every 2-4 days. Something often, would have to check with a cell monitor.

That would mean the battery lifetime could be as little as slightly under 3 years to hit 500 cycles. Maybe less.

Anyways it's not a huge deal, just looks like they have the same problem Teslas had early on : too many battery sucking smart features, and inadequate 12v lead acid chemistry to handle the load. Ohmmu already has a drop in lithium iron phosphate battery for $440, I guess I will swap one of those in once the 12v warranty expires in years and the 12v inevitably fails a few months after.
 

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2022 Preferred AWD LR Ioniq 5
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It could be that the 12V battery got used extra hard exactly because of the dealer logic update. I think quite a few people on here have 12V battery monitors, and I wonder what the lowest SoC they see is.
 

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... I think quite a few people on here have 12V battery monitors, and I wonder what the lowest SoC they see is.
My BM graph from last Friday showed a fairly low reading, but I'd been playing around with the radio & had the doors and boot open for quite a while.
As you can see, the system automatically gave it a booster charge after I'd locked it up.

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I think it is putting a cycle on the 12v battery every 2-4 days. Something often, would have to check with a cell monitor.
That would mean the battery lifetime could be as little as slightly under 3 years to hit 500 cycles. Maybe less.
The battery gets a boost whenever the BMS algorithm deems it necessary, which is usually several times a day if the car is being driven every day, or as low as once every 2-3 days if left unattended.

The expected life of a regular lead acid battery in an ICE car is usually somewhere between 3-7 years.
As an EV's 12V battery doesn't have to suffer the heavy current discharges of a starter motor several times a day, one might expect it to have a longer life.
 

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Discussion Starter · #4 ·
The expected life of a regular lead acid battery in an ICE car is usually somewhere between 3-7 years.
As an EV's 12V battery doesn't have to suffer the heavy current discharges of a starter motor several times a day, one might expect it to have a longer life.
We'll know in 3 years or less but this kind of cycling frequently stranded Tesla's. Worse they didn't have a manual key or frunk and they hid the battery itself because they were ashamed probably. It's the number of cycles not the current I am concerned about.
 

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I think if you are dropping to 12.5 (or less) 4 times a day, your battery life will be very short. And that is why this forum and every other EV forum is crowded with 12 volt battery issues.
 

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It's the number of cycles not the current I am concerned about.
Tell me what you consider the definition of cycles?

I would define it as a near total discharge to around 20%, followed by a charge to around 100%
This is certainly not what is happening in the daily use & charging of the I5s 12V battery, its more of a topping up trickle charge whenever needed.

Regular heavy discharge currents, typically 300A when using the starter motor on an ICE car, would have a far greater effect on a batteries overall lifetime than the regular topping up we have with an EV
 

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Discussion Starter · #7 ·
Tell me what you consider the definition of cycles?

I would define it as a near total discharge to around 20%, followed by a charge to around 100%
This is certainly not what is happening in the daily use & charging of the I5s 12V battery, its more of a topping up trickle charge whenever needed.

Regular heavy discharge currents, typically 300A when using the starter motor on an ICE car, would have a far greater effect on a batteries overall lifetime than the regular topping up we have with an EV
You are confusing lithium and lead acid chemistry. Lead acid batteries are rapidly destroyed by any significant usage at all or discharge below 50 percent.
 

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You are confusing lithium and lead acid chemistry. L
I never mentioned about Lithium batteries?
...Lead acid batteries are rapidly destroyed by any significant usage at all or discharge below 50 percent.
Just where are you getting your info from?

An EV's 12V battery has a far easier life than one in an ICE car.
What would make you think it discharges below 50%?
 

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Discussion Starter · #11 ·
Darn!!
My 45 years as an auto-electrician were a waste of time, I should have enrolled at the Battery University

:D:D:p:D:D
There's no shame in not knowing something. Did your 45 years include time in battery test facilities where you actually plot out how many cycles a battery lasts or nah? Because that's the knowledge you are missing.

You know from your yoe that obviously older batteries have poor output cranking amps, but you don't actually know exactly the roles the variables of (calendar age, vibration, temperature, cycles at different DoDs, and charge/discharge currents) play in battery life.

How would you even know that? You just probably fixed vehicles as they come in, and noticed that 'if there's more than <n> months of usage on this 12v it's probably bad'.
 

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Discussion Starter · #13 ·
Yep..... 4 year apprenticeship & 40+ years hands on high current drain oily equipment.
(Wish I'd gone to Battery University though - sounds very clean)
I don't discount your experience Restyler but just try to know what you don't know. In this case, the critical number is in the chart at the top of this page (from a battery university article) - with 50% DOD (meaning a cycle is "charge to full and drain slowly down to half then charge to full again") - you get about 500 cycles before the battery is dead. (in STP conditions). That means that if that event happens every 2 days on our Ioniq 5s, we'll need new batteries in 1000 days or slightly under 3 years.

If the car lets it drain down to 30% - which is what I empirically discovered at the top of this thread - you get even less cycles. Battery will be dead in 300 cycles, or under 2 years.

Which is what many people complain about in other EVs including other Hyundais and Teslas - a 12v battery that doesn't make it even 2 years.
 

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Discussion Starter · #15 ·
Don't you know. the self proclaimed internet "Experts" ALWAYS know more than anyone that actually does something for years. Its obvious really. :)
Sources by real life experts > real life experience at the wrong layer. I currently work at the device driver layer at a silicon company but I don't claim to know how long the silicon gates last. I would trust an internet expert who cites a source over my direct experience.
 

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Tell me what you consider the definition of cycles?

I would define it as a near total discharge to around 20%, followed by a charge to around 100%
This is certainly not what is happening in the daily use & charging of the I5s 12V battery, its more of a topping up trickle charge whenever needed.

Regular heavy discharge currents, typically 300A when using the starter motor on an ICE car, would have a far greater effect on a batteries overall lifetime than the regular topping up we have with an EV
And your definition would be wrong.
A charge cycle "can be a complete full charge to discharge or a series of partial drains adding up to the battery’s capacity."
Lead acid batteries are rapidly destroyed by any significant usage at all or discharge below 50 percent, and my qualified guess is that the time from production of the 12V battery, until first charge would be up to 6 months. From installation in my car until first charge was 3 months, and I had 41% SoC on my 12V when I received the car.

What would make you think it discharges below 50%?
Did you even look at the picture in the first post?
Mine was also discharged below 50%(41%) when I took delivery. Charged it to 100%, and haven't seen 50%(61% at lowest) again after that.
But my guess (qualified again) would be that there's 1000s of EV drivers out there (especially with brands that have a long travel from factory to customer) with 12V batteries with a too low SoC(below 50% like OP) and SoH.

And that's probably why we see so much 12V problems in EVs; long travels on ships and new algorithms (different from ICE's) on how the high voltage battery should charge the 12V battery.
 

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And that's probably why we see so much 12V problems in EVs; long travels on ships and new algorithms (different from ICE's) on how the high voltage battery should charge the 12V battery.
Yeah, as I’ve said before:
  • Vehicle is assembled
  • vehicle is charged to about 50%
  • test driven in South Korean test track
  • driven on to ship
  • Battery is isolated (for safety reasons) & 12V battery ceases being charged
  • transported to destination country
    • here Aus has advantage - shipping takes 3 weeks to us, some countries take 3-4 months
  • battery is reconnected
  • car is driven off ship
  • clears customs
  • delivered to dealer & customer
Not all that surprising Europe & North America have 12V battery problems.

[edit: interestingly the drivers that test & load the vehicles on ships are amongst the highest paid Hyundai workers. If you look at what‘s involved it’s understandable]
 

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Discussion Starter · #19 ·
Update: I put a battery monitor on the 12v. Now that I can see the actual logs and look at a charge of SOC vs voltage.

The 12v starts each cycle at ~13 volts which is above the "full" SOC for a flooded lead acid battery. Apparently this 'surface charge' is normal. And it discharges down to 12.5 volts, which per the below chart is about 90% SOC.

So every 18-30 hours (haven't run this long enough to be sure the interval when the car is truly idle and has not been touched or driven) it charges the 12v for about an hour.

This means it puts a 10% DoD cycle on the battery about once a day, which means per various charts online it has a lifespan somewhere around 1000 cycles, or over 3 years. It has an idle current draw of about 3 watts average which seems reasonable.

I also found online the reason they picked this battery - it has a cost of about $120 though it's hard to actually get it shipped to you for anywhere near that due to it's weight and toxicity etc.

At that cost the lithium iron aftermarket replacements aren't worth it - just swap it every 3 years.

It will be interesting to see what happens as the battery fails. In theory a badly degraded 12v should still be perfectly fine, as there is almost no current required to 'start' an Ioniq 5. 10-20 amps tops.

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Update: I put a battery monitor on the 12v. Now that I can see the actual logs and look at a charge of SOC vs voltage.

The 12v starts each cycle at ~13 volts which is above the "full" SOC for a flooded lead acid battery. Apparently this 'surface charge' is normal. And it discharges down to 12.5 volts, which per the below chart is about 90% SOC.

So every 18-30 hours (haven't run this long enough to be sure the interval when the car is truly idle and has not been touched or driven) it charges the 12v for about an hour.

This means it puts a 10% DoD cycle on the battery about once a day, which means per various charts online it has a lifespan somewhere around 1000 cycles, or over 3 years. It has an idle current draw of about 3 watts average which seems reasonable.

I also found online the reason they picked this battery - it has a cost of about $120 though it's hard to actually get it shipped to you for anywhere near that due to it's weight and toxicity etc.

At that cost the lithium iron aftermarket replacements aren't worth it - just swap it every 3 years.

It will be interesting to see what happens as the battery fails. In theory a badly degraded 12v should still be perfectly fine, as there is almost no current required to 'start' an Ioniq 5. 10-20 amps tops.

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I had the same issue with the 12v battery after I got the car from the dealer. Was seeing low voltages of 12.3, 12.4, 12.1 11.7, etc. Disconnected the negative cable from the battery terminal, and attached a de-sulfating charger for about 1 day and a half. Have done that twice since, and battery reads a happy 12.6 to 12.8v volts whenever I go to measure it with a volt meter every now and then

 
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