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Discussion Starter · #1 ·
I just came across this nugget in the manual which seems to speak directly to a question people keep asking about the 12V system in the I5/EV6: If the 12V battery gets low, it WILL automatically engage the DCDC converter to recharge it from the HV battery, HOWEVER, if it has to do this "more than 10 times consecutively" it'll just stop doing it under the assumption something is wrong with the 12V battery. "Consecutively" is undefined - perhaps it means "10 times before the car has been started again to drive," or perhaps it means "10 times in a day," or who knows. What we do know is that 1) normally, you can park the car for a month or two and expect it to work no problem 2) some people have issues where the battery dies and they have to jump the car anyway, particularly with the I5 3) an actually-faulty 12V battery with high internal leakage current could cause (2), if the car determines it's recharging too often.

So long story short, you car SHOULD keep its 12V system topped up indefinitely, ready to go when you finally return, but if you install enough continuous aftermarket load on it it may simply stop doing that, under the false impression that the battery is faulty.

I have been playing with a battery monitor lately and it seems like it tops up the 12V no more than once a day or so, but it's tough to tell since I have been driving regularly.

I intend to install a 5W load on it to see how much continuous demand it'll tolerate, but want to get a better/longer baseline first.

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KIA EV6 Wind AWD Glacier White
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Good find Alex. I was thinking to replace the battery with a Lithium car battery in order to save on weight and allow for deeper discharge. So far I could not find one that has similar dimensions.
 

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2022 EV6 Wind AWD Extended
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The battery is a standard Group 47 battery.
The battery may be a standard group 47 in size but it's not a standard lead acid battery. It's a calcium lead acid battery which takes a higher voltage to initiate a charge. That higher voltage from the built in charger can cook a standard lead acid battery. I would suggest reading about them.
 

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The battery may be a standard group 47 in size but it's not a standard lead acid battery. It's a calcium lead acid battery which takes a higher voltage to initiate a charge. That higher voltage from the built in charger can cook a standard lead acid battery. I would suggest reading about them.
Thanks Ronsk74, so far the original battery is not giving me any trouble. If ain't broke why fix it? I have the smallest Lithium 1000 A jump starter that I could buy in the frunk just in case. The car does not need much power to start the computer and engage the high voltage battery relay.
 

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Thanks Ronsk74, so far the original battery is not giving me any trouble. If ain't broke why fix it? I have the smallest Lithium 1000 A jump starter that I could buy in the frunk just in case. The car does not need much power to start the computer and engage the high voltage battery relay.
Ya, I've been thinking about one of those. So far I think the number of owners having problems with the 12v battery is still pretty small.
 

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Hv DC converter for 12V battery is like smart battery charger. Do not attempt to use different chemistry besides specified by Kia.
This inverter has various different algorithms specifically designed for chemistry EV6 is using for 12V battery. Lithium ion, Lithium iron and etc are not to be used.....unless specified changes are made on the converter software side. Conventional alternator on ICE and converter on EV are completely different animals. To get better understanding search for smart 12v battery chargers that have multiple different stages for charging.
 

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Hv DC converter for 12V battery is like smart battery charger. Do not attempt to use different chemistry besides specified by Kia.
This inverter has various different algorithms specifically designed for chemistry EV6 is using for 12V battery. Lithium ion, Lithium iron and etc are not to be used.....unless specified changes are made on the converter software side. Conventional alternator on ICE and converter on EV are completely different animals. To get better understanding search for smart 12v battery chargers that have multiple different stages for charging.
This discussion was about a lithium jump battey in case the 12v battery died. There has been talk of changing to different chemistry 12v batteries in some posts but I haven't been part of those mainly because those would require different charging characteristics.
 

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This discussion was about a lithium jump battey in case the 12v battery died. There has been talk of changing to different chemistry 12v batteries in some posts but I haven't been part of those mainly because those would require different charging characteristics.
Thanks.
I'm just trying to make others aware of how different EV actually is vs what they learn to know.
I have come late to the party on this forum but I will try my best to keep people aware and help them understand this vehicle.
 

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ev6 wind
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I know, I could not find a lithium Group 47 battery yet, I will keep searching.

Thanks.
Have you seen the offering from Lithiummoto.com/tesla-12v-battery ? a lot less than the quoted alternative.
My question is: Just HOW would the charging algorithum differ because of a lead or lithium chemistry ?...
based on what ?
 

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Lithium batteries have a different charging "profile" than lead acid batteries, basically meaning that their starting and ending voltage and current charge rates are different. The converters in most EVs are controlled and programmed for a specific chemistry. You may be able to charge a 12v lithium in the EV6 but it may not finish the charge correctly which can reduce its life. You can also over charge a lithium battery with a lead acid charger which again can shorten its life.
 

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The LiFepo4 battery normal top charge is to 14.4V.
Victron specifies two ranges: 14.2V…14.6V for a “normal” charging cycle on their AGM's. as a good example.
Whether the profile is CCCV or a variation the battery will be charged, as the final voltage isnt fixed.14.2, 14.3, 14.4....
So, that eliminates the voltage angle...
SO, what else could it be ?
Is their a tech person from Kia that could answer this ?. I dont want to go round and round speculating.
 

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Discussion Starter · #16 ·
To clear the air a bit: lithium ion batteries and lead acid are completely different, and require such different charge handling that you absolutely cannot interchange them. This is precisely why lithium ion 12V car batteries designed to replace lead acid in vehicles come with their own charge controller/battery management system built in.

there are still all kinds of nuances replacing one with the other, but when we talk about swapping in a lithium ion car battery, it’s a specific product designed for the task and not some box of raw cells that’s going to blow up if you drive too long and overcharge it.

because if it WERE a box of raw cells, that would happen.
 

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The LiFepo4 battery normal top charge is to 14.4V.
Victron specifies two ranges: 14.2V…14.6V for a “normal” charging cycle on their AGM's. as a good example.
Whether the profile is CCCV or a variation the battery will be charged, as the final voltage isnt fixed.14.2, 14.3, 14.4....
So, that eliminates the voltage angle...
SO, what else could it be ?
Is their a tech person from Kia that could answer this ?. I dont want to go round and round speculating.
Onboard DC-DC converter is like smart battery charger.
It has multiple different profiles depending on voltage, temperature, energy used from 12V battery.
Going with another 12V battery chemistry that dosent have ability to mimic original chemistry DC-DC converter is setup for will bring more issues than good.
DC-DC converter is possible to setup for different types of chemistries but this is only possible by Kia engineering department.
And chances of getting it setup for different chemistry are very slim.
You can go with bigger ah battery with same chemistry, but DC-DC converter algorithm will still treat it as 12V stock ah battery. You will definitely have longer life with more ah battery when vehicle is asleep and it will require less booting up of traction battery to recharge 12V battery.
 

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I guess my Q is; .. How does the DCDC converter , as a smart charger . " know " whether the battery is lead or lithium ?
By software calibration values set from manufacturer. There is sensors that measure current flow, temperature, voltage and internal resistance for 12V battery. If this values are out of calibration values lead vs lithium it will trigger errors.
Lithium has different values regarding internal resistance, voltage, temperature and how far they can be discharged. Lithium battery 12V needs separate lead or software logic to keep cells warm in winter conditions.
This can be done by onboard 12V battery BMS to keep lithium battery safe in cold weather. But onboard DC-DC converter will see this as unknown 12V battery losses when there is energy used by 12V battery bms to keep battery warm.
Simply explained DC-DC converter needs to be set for lithium battery to operate properly.
Some aftermarket lithium battery producers will try to mask this by mimicking different cell chemistry using 12V battery own BMS
 

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I get what your saying, but, I'm looking for the most probable value the car might sense for;
IR..? , well thats a moving target depending on temp, capacity and SOC. so, i doubt its that.
AGMs have a low IR anyway, very similar to lithium.
Current flow, well i dont see how a diff current would come out of the batteries.
If the car wants 10Amps, it will get 10 amps.
Temp; I dont see any difference, we're not talking about any heavy hi rate discharges.
ALthough the charging profile is different, the lithium can accept a lead profile even though it may not be fully charged at the end.
VOltage, is the only thing i can see... ie, voltage drop compared to the current draw. the Li would be less, although, that also depends on the Ah of the battery.
So,
I'm still stumped. We dont know the answer. Maybe i should contact the eng dept at Kia. to find out. if thats humanly possible
 
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