Trick to avoid low 12 V battery on your EV

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[dindu]

I just found that my new Hyundai Kona EV has a Utility Mode. Basically you can put the car into this mode if you are going to leave it for a while and it basically tells the traction battery to power all the internal electric which normally drain the 12v battery. This mode is switched off as soon as you next press the Start button but it sounds great for times such as leaving the car in an airport car park.

[PaulvanDruten]

the manual at page 23 says:
- Intelligent Charging -
The 12V battery SOC (State Of Charge) is constantly
monitored, when the vehicle is power OFF it is possible,
under certain conditions, that the HV battery will
automatically charge the 12V battery to ensure the
vehicle starts. This function will activate and switch off
automatically.
Note: The system will suspend intelligent charging if a
fault is present, when starting or the vehicle is being
charged by an external device.
Note: The driving range will be reduced after
intelligent charging.
Note: The intelligent charging function is suspended
when the high voltage battery is in a low SOC.

[SirHackaLt.]

I didn’t think MG had an app for the car. Good to see one working.

[cypercharged]

Scanmytesla now shows 12V battery voltage 👍

[flemlion]

In the VW ID app I found a setting to allow the use of the high voltage battery for app functionality. It was turned off by default and has a warning that it impacts range. Both seem stupid to me, because if the 12V runs empty, the range of the car is 0 because it isn't going anywhere

[DavidNGacuca]

You beat me to it Bjorn; I've been wanting to make the same video about the Nissan Leaf 40. I run out battery on my driveway after having left the lights on all night. I discovered that there are two methods to charge the Leaf's 12V battery. One being a level 2 charger and the other, turning on the heating or cooling remotely ( preconditioning). Apparently, the leaf does charge the 12v battery when off at some intervals, but people have still experience flat 12v batteries. With Leaf Spy, I was able to determine that the 12v battery was being charged by being within the Bluetooth distance communication of the obd dongle, as it indicated a battery voltage of 14.v and nearly 70 amps charging. BTW, if the 12v battery is completely flat none of the above works and only a jump start will do the trick. I now keep a NOCO 40 Lithium ion batt jump start in the boot to mitigate against this eventuality.

[davidnicholson]

A tip I saw on a youtube channel reviewing a Toyota BZ4 which had a low charged 12 V battery is to start the car in neutral and fasten the seatbelt. Of course this was after manually unlocking the door and using jump cables. In my case, I have installed permanent charging cables to the battery which, when needed, are fast connected to a CETECH charger. The bonnet is closed and the charger placed at on the bonnet by the wind screen. This setup is especially useful when the car is not used for some time. The CETECH delivers trickle current thereby maintaining the battery, All EV owners should have this setup especially when the car is left for extended periods. Also, battery life will be extended. Search youtube for the CETECH tutorials.

[darrylstevens]

I bought a small solar panel from my local auto store approx
14" X 4" and plug in my 12V outlet when leaving the car parked for extended periods of time. Works even on cloudy days! Place it on the dashboard and provides a trickle charge to keep your 12V battery happy 😊

[ecospider]

I have a 2013 Leaf that I only drive every 2 weeks. I have to turn on the heat remotely twice a week or I risk a dead battery. Another annoyance is when you start the Leaf it doesn’t enable a connection to the big battery till the car is completely started which takes almost 30 seconds. So a lot of those portable jumpstart packs don’t help because they pulse the energy 10 seconds on 10 seconds off. So the computer never starts completely.

[ndcp]

On the Zoe, if you get the error "ELEC System (something)" it means that the 12V battery is low. To charge it up park it and let it unlocked for some time (at least 15mins). If it's unlocked the DC-DC converter will charge up the 12v battery. So yeah, hope this helps somebody!

[raylab]

Works on Hyundai Ioniq 5!
The Ioniq 5 do also check the 12v system, but not continuously. Only at specific times, perhaps ever 4 hour. Then, if the 12v battery is bellow a threshold (12, 6), the dc-dc converter kicks in for an hour IF the main battery is above 30%SOC. Also, it the car needs to do this more than (perhaps) 3 times in a row, then the top-up will stop, assuming there is a fault somewhere.

[AlexJPetrov]

The charging of the 12v should be automatic. Why did they made it so you have a big battery full and can not use your car because a small battery is low? Sabotaging the EV like that... Shame!

[bradallen]

Tesla always had trouble with its 12V battery in the first few years. It was a big problem. I think they improved it a bit.

[george]

I thank you very much for your advice because your idea worked on my Nissan Leaf Plus remote climate control.
A big battery started to kicked in to the heater inside the car. That means electricity went to the small battery also.

[JustWastedHoursHere]

When you check the 12V battery voltage when the car is on, you're actually checking the 12V system which will report 14 or so volts most of the time because the DC-to-DC system will report its maximum voltage, whereas if you check it with the car off then the 12V system is powered entirely by the battery only. That's why that number changed so quickly when you checked it with the car on and then off.

On this note, there is a valuable thing you can do with both electric and gas cars with one of those volt meters that plugs into your cigarette lighter (if your car has one):* Turn the car on to 'ACC' without starting it. This is the actual voltage from the battery. If it's below about 12 volts then you should probably consider having your 12V battery tested and/or replaced soon. If it's higher than that then your battery is probably fine. Now, if you then start the car the voltage read from the device will show what your charging system is putting out, either an alternator (gas and diesel cars) or DC-to-DC device. It should read 13.5 to 15 volts generally. If it's less than that (or higher) then you might need to have that looked at because it could mean your alternator/DC-to-DC is not working up to spec.

* If not, you can hardwire one into your electrical system. Search Amazon or google for 'hardwired car charging system analyzer'.

[MichaelEricMenk]

A 6S Lead Acid battery at rest:

12.8V = 100% SOC
12.6V = 75% SOC
12.3V = 50% SOC.

Never let a lead acid bettery go under 50% .

BTW, my EV also charges the 12V when the car is charging.

I would assume that most EV turns on the 12V charger while preheating due to the high power usage of the fan.

BTW, this is not a EV problem, all the 12V equipment like car alarm and remote unlock uses power. People I know working at oil rigs have installed PV in their ICE car to prevent the battery from draining while offshore..

[allanm]

It's normal that the voltage will drop as soon as you draw any current from a 12V battery. But when you stop drawing current, the voltage will slowly get back up to the 'normal' voltage for its SoC.
Likewise when you charge a 12V battery, the voltage will immediately go up to the level of the charger. But when you stop charging, the voltage will again slowly go down to the 'normal' voltage for its SoC. So its not a lack in the dc-dc converter.

[omar-sjfj]

Thanks for the trick. It works also for the Nissan Leaf 40kwh. The dc-dc starts at the same time at the Air conditioning.

[smijas]

Volkswagen/Audi --> enable DC to DC converter > start either the rear-window heater or one of the seat-heaters. THEN the 12V system will recharge.

[brfsa]

Dang man, thats a really awesome trick. I didn’t even know about the pre cooling, sometimes i have to park my MG in the hot sun.