[HiThere!]

I did a lot of searching and reading and now I'm asking, when is the 12 volt battery invoked? I'm sorry if this is a dumb question but I figured this was the best place to ask even stupid questions LOL

I don't drive everyday. Sometimes I don't drive for a week. When I'm "playing" with my EV6, I have it powered on, not in ACC. I'm looking to find out first, when is the 12 volt battery draining and second how do I avoid it draining?

I am not even slightly mechanically inclined nor do I understand electricity at all (sorry in advance) but, in my defense, I don't know much about ICE either but have many friends that do 🤣

 

[DMiller]

Most of the electrical parts that aren't unique to an electric vehicle are run from the 12V line. That includes powering the instrument panels, infotainment unit, USB ports, all the interior lights, the headlights, tail lights, turn signals, radar and ultrasonic sensors. power brakes, power steering, cameras. I'm probably forgetting some - there's so much.

The high volt system runs the air conditioning compressor, and the motors that move the car. The electrical conversion units for the V2L (700V to 120V) use both the 700V and 12V.

The 12V system powers the main computer and all the others throughout the car. The 12V battery is always going to be used when you have the car in ACC, ON, or RUN. There is also some current drawn from it in OFF, but it's not too great.

When the car is ON there is a converter to recharge the 12V battery (as an alternator would), getting power from the 700V battery to charge the 12V battery.

Even when you shut off the car it monitors the 12V level and will turn on the converter to keep it charged if it gets low between days you drive. (A light on top of the dash shows this when it is happening). You shouldn't need to worry about the 12V battery draining unless the 700V battery is extremely low.

 

[benanderson89]

The 12V battery also controls the battery contactor. When the car is off the 700v battery isn't actually connected to anything, and when the car is started the 12V powers the solonoid to connect the 700v to the rest of the vehicle. It's the "clunk-click" sound you hear when you press the starter button.

 

[HiThere!]

Great info, Thank YOU! Again, possible stupid question alert =) When does the 12V recharge? When the car is plugged in? When you're driving (like an alternator on an ICE)?

 

[DMiller]

Yes to when you're driving, and yes to when the car is off (intermittently, as needed). I don't have my EV6 yet (but it's getting real close now), so I'm going to make a guess on the third part of this question: yes (?) to when the car is actively charging.

 

[WiscEV6]

I think some manufacturers have been talking about changing to a 24V or even 36V system for peripherals. Sadly for most EV or PHEV, if the 12V battery goes, then the vehicle is dead even though there is a massive battery within feet of the 12V.

 

[Ev6ride]

Hello, I have a ev6 and had it for 4 months, the 12v battery is charged as soon as you start the car. I wouldn’t be so sure to trust the ”auto-charge” of you don’t drive your car because after I had the car for 1 month I left my car on the airport (plugged in to be charged) and when I came home after 10 days the 12v battery was totally dead, have seen that I’m not the only one. Have been reading a lot but can’t flnd good info, found one guy WHO said that on a ev6 you need ti activate the function for auto-charge 12v battery. Have looked around a lot in the menus but can’t fond that setting and it seems to be off at my car. If someone knows anything about this setting please inform me. The workaround I have found now is to buy a portable jump starter for worst case scenario (next trip) and verifyed that when you activate your ACC through the app the car also charges the 12v battery. So until proven wrong and find the setting I will be activacting my ACC remotely once a day when I leave the car on a AirPort again.

 

[DMiller]

I'll be watching this when I get my car - I have a 12V battery monitor that I will attach to the battery to continuously track its voltage.

But in another thread, someone pointed out the page in the owner's manual that says the HV battery will charge the 12V battery when it is low, and there is a light to show that it is happening. Several other people have seen that light come on when the car was parked in their garage, and asked what it means.

According to the EV6 owner’s the when the 12v battery is discharged it is charged from the 800v battery.
View attachment 3455

 

[DMiller]

Another person checked the exact same question on his EV6. He says it does periodically charge the 12V battery when the car is OFF (unless the hood is open).

After seeing this YT video and reading about dead 12V batteries with EV6/Ionic5, I decided to make myself a battery monitor using a ESP8266 I had lying around to track how my car works. If you want to DIY, can build one from here for less than $5.

Observations after leaving the car idle for 3 days, HVB at 70%, not plugged in, garage temps 30-50F:
(ignore the spike around 3/31 as that was when I turned the car on)

• every time I open the Kia app or log into my Kia owners portal, the car wakes up (dips shown in red circles)
• the LVB automatically gets recharged from the HVB - this appears to happen when the car is idle and voltage drops to 12.5-12.6V. The car also wakes up and this is when the orange light on the dash comes on. There does not seem to be a time pattern
• Charging at 14.8V lasts for slightly more than 1hr
• when left idle, it takes more than 1 day for the car to drop from fully charged to 12.6V at my 30-50F garage temps
• Front hood must be closed for LVB charging to activate. When you pop the hood, it stops. Opened doors/trunk is fine.

You can draw your own conclusions but based on this, I'm fairly comfortable leaving my car when going for long vacations. The car seems smart enough to recharge its LVB. I will continue to monitor longer to see if anything changes to this charging pattern or when HVB drops below a certain %.
View attachment 4303

 

[Wayne]

Hello, I have a ev6 and had it for 4 months, the 12v battery is charged as soon as you start the car. I wouldn’t be so sure to trust the ”auto-charge” of you don’t drive your car because after I had the car for 1 month I left my car on the airport (plugged in to be charged) and when I came home after 10 days the 12v battery was totally dead, have seen that I’m not the only one. Have been reading a lot but can’t flnd good info, found one guy WHO said that on a ev6 you need ti activate the function for auto-charge 12v battery. Have looked around a lot in the menus but can’t fond that setting and it seems to be off at my car. If someone knows anything about this setting please inform me. The workaround I have found now is to buy a portable jump starter for worst case scenario (next trip) and verifyed that when you activate your ACC through the app the car also charges the 12v battery. So until proven wrong and find the setting I will be activacting my ACC remotely once a day when I leave the car on a AirPort again.

What the...? It was dead after only 10 days of no use? I've been on two week trips, and both ICE cars started with no issues.

From the EV6 Owner's Manual on the 12v battery (8-17):

• If the vehicle is not going to be used for an extended time, disconnect the battery cables.

There's a HUGE 77.4 kWh battery right there that it could tap. I hope these issues are just one-off's, or somebody wasn't thinking. Of course, "extended time" isn't defined. Personally I wouldn't think 2 weeks is an "extended time". I would think of that more in months, than weeks.

 

[klingon]

Another person checked the exact same question on his EV6. He says it does periodically charge the 12V battery when the car is OFF (unless the hood is open).

The 12V battery also gets charged when you're charging the HVB. I've tracked this on my batt monitor. A lot of people measure their 12V batt right after they open the driver's door, pop the hood and see 12.2V and freaks out. Keep in mind that whenever you open the doors, the car wakes up and this will drop the batt voltage and will continue to drain the 12V battery. The EV6 batt is not very big amp-wise. The car will not go back to sleep until you close all the doors. If you want to properly measure the 12V batt, close all doors but leave the hood open, wait 10-15 mins for the car to go back to sleep and battery to stabilize, then measure. From my tracking, the car goes back to sleep around 5 mins after all doors are closed. Since I started tracking a few wks ago, my EV6 has been self-charging every 1-2 days when it drops down to around 12.5V. Longest idle time I've tested is 1 wk, so dont know if it will continue to self-charge if left idle for 1 mth.

 

[DMiller]

Does anyone know why Kia might recommend disconnecting the 12V battery if the car won't be used for "an extended time"? If the high voltage battery is reasonably well charged, that's way more juice than needed to keep the 12V battery topped up. 77kWh can recharge 720Wh about 100 times over.

 

[smoove ride]

What DMiller said up above.. but the short answer I've gotten is it's a DOT requirement that the 12V battery is there as a backup to the brake/antiskid system in case the HV battery dies. I thought it was crazy the first time I popped the hood on an EV years back and saw a 12V battery under the hood.

On that note, I own a 2013 Leaf and had to replace the 12V battery recently due to it going bad. It's common on EV's to have to replace the lead-acid 12V batteries with something a bit more resilient (AGM) due to how EVs charge the 12v battery and it seems to kill lead-acid batteries. I didn't check, but what does the EV6 come with?

 

[thomasez]

Here in Norway (prolly whole of Europe) there seems to be no "HV on light". This annoys me as it's useful.

Had the car for forimware upgrades and it came back with "Caution" and a red battery in the app. That did not go away until the day after. Which means the car does not charge the 12V battery until way after it's so low it warns about it.

 

[tangey]

I assume the main battery powers the electric engines and nothing else, other than to keep the 12V battery topped up as required (just like a regular engine would). The 12v battery does everything that it does in a regular engined car. The reason is that general electrical circuitry in a car has been 12volts for virtually forever, and thus every single electrical component designed for car use is designed to have a 12volt input.

Clearly there must be a reason why car manufacturers decided not to derive 12volts from the 400v/800v battery, and prefer to use a separate battery for that, it doesn't obviously come to mine. Could be just so that like a "regular" car, if you run out of fuel, the ancillary functions of the car continue to operate.

 

[thomasez]

12V (or 48V as some cars have started using) is a security thingie. You do not want the 800V be live in the car all the time.

 

[Ev6ride]

What the...? It was dead after only 10 days of no use? I've been on two week trips, and both ICE cars started with no issues.

From the EV6 Owner's Manual on the 12v battery (8-17):

• If the vehicle is not going to be used for an extended time, disconnect the battery cables.

There's a HUGE 77.4 kWh battery right there that it could tap. I hope these issues are just one-off's, or somebody wasn't thinking. Of course, "extended time" isn't defined. Personally I wouldn't think 2 weeks is an "extended time". I would think of that more in months, than weeks.

Yep, and you should have heard my wife complaining on ev cars and Ehh I had to be the first one buying 😂

was washing my car now and had radio on, so it’s about 10 minutes and got a warning start the car and drive after that ti probably charge the battery. Sittning in the car now and monitoring the battery have dropped down to 12.2v and still no charging or orange light in the Hood. Will go to the dealer again because when I visited them after the problem at the AirPort they said it was complettely normal and I was like ok… in which part of the World is that okey😂

 

[DMiller]

My understanding is that the orange light on the top of the dash only comes on when the car is OFF and the system turns on the HV to charge the 12V battery. What was the state of the Power button when you captured that screen? Did you turn the system ON or was it in OFF or ACC?

 

[ronsk74]

What DMiller said up above.. but the short answer I've gotten is it's a DOT requirement that the 12V battery is there as a backup to the brake/antiskid system in case the HV battery dies. I thought it was crazy the first time I popped the hood on an EV years back and saw a 12V battery under the hood.

On that note, I own a 2013 Leaf and had to replace the 12V battery recently due to it going bad. It's common on EV's to have to replace the lead-acid 12V batteries with something a bit more resilient (AGM) due to how EVs charge the 12v battery and it seems to kill lead-acid batteries. I didn't check, but what does the EV6 come with?

FYI, an agm battery is a lead acid battery but with woven fiberglass inside to reduce stratification that you get in liquid lead acid batteries. Since the kwh charge rate is lower for an agm than a regular battery your comment that the hv converter kills a regular battery but wouldn't harm an agm battery simply isn't correct. If the hv battery maintainer kills any 12v battery in your car, take it to the dealer.

 

[Catbreath]

I would recommend picking up a rechargeable lithium ion jump starter and keeping it in your trunk in case ur 12v battery drains