Trick to avoid low 12 V battery on your EV 

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.

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

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.

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.

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!

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!

Teslabjørn opens the front left side door to enter the car and then "Oh sheeet, wrong side. I forgot I'm in Thailand LOL :-)

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.

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 😊

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.

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.

For cars built on E-GMP platform (Ioniq 5 & 6, EV6, Genesis GV60 etc) and equipped with the V2L adapter, a suitable trick to top up your 12V battery is to plug that V2L adapter in. No need to power it up and use it to run some external devices. This might seem quite odd, but it definitely does the trick. Sadly, at least Kia Connect app doesn't display the voltage of the 12V battery. On more general level, I'm still keeping up hopes that the 12V batteries in EVs cease to exist at some point. While basically everything inside the car uses 12V voltage, surely this doesn't mean that a very old invention like lead-acid battery must be used to provide that voltage.

10-20 minutes of charging doesn’t do much good for a 12V battery. Worst case could be 12-24 hours before the battery is fully charged. Battery characteristics and properties for 12V AGM/lead-battery is completely different from high voltage lithium batteries in EVs.

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'.

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.

According to WeberAuto, Newer Tesla's now have a 16v Li special Battery ilo 12v Lead acid 😢

Nice video, thanks. Just wondering how fast the 12V battery drains when the MG is not in use (parked)

Thanks Bjorn This is a running topic in the 1st gen Ioniq section of Speak EV that I have contributed a few posts. I have concluded that the problem is a poor charging algorithm exposed by an even poorer OEM 12 V battery. Replacing the OEM battery is the only practical way round it as I can't rewrite the algorithm and your "trick" isn't really a long term fix. Keep up the great videos.

I own Nissan e-NV200, it recharges 12V battery itself once in a while. First I'm getting an email saying 12C battery voltage critical, with voltage in the brackets, and then later I'm getting another email with higher voltage already, saying 12V voltage been restored. When DC-DC recharging 12V battery - 3rd LED is flashing on the dash, not first one, but third one. I'm also using OVMS to see battery stats and precondition the van.

Hyundai removed the option to disable the Battery management system on all Kona's EV. I still have had a dead 12V battery for no reason I can figure out. The issue might be the BMS falls behind on keeping the 12V battery charged and if you have a bad sulfated 12V battery, the BMS will stop trying after so may attempts. Tesla is working to solve this issue with new accessories that will be 50V DC, like what Lucent uses for 5 ESS switches (phones). They want to get rid of the lead acid and use a 50V LiPo batery instead, smart thinking.

3:30 Sheeeeeeet!

Great video! I have a Kona and there is a setting to allow the car to monitor the 12v battery to keep it topped up. Why its not just on permanently is silly.

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

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.

I think all the VAG cars, Skoda, CUPRA etc has a low voltage protection option in the app. It’s confusingly named “High Voltage Battery Protection” but actually is protecting the 12V. ABOUT HIGH VOLTAGE BATTERY PROTECTION Power of the low-voltage battery is saved by turning off non-necessary functionalities. This extends the availability of online services. Other important services, such as emergency services, are also guaranteed for as long as possible. HOWIT WORKS The HV battery can be set to provide more power and ensure the minimum basic functionalities of the vehicle. Its use may affect the range.

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

I have the leaf 8 years old and never get 12v battery problem, it gets down to 12.16v or even lower but there is no problem to start the car. Easy way to deplete 12v battery is to turn on lights and get windows down and up again. But if you have problems anyway you must simply change the 12v battery

I’ve seen videos on problems with the Tesla 12 v battery. Before the latest updates it was a huge issue. Worse than most EVs because you had to pull huge parts out of the way to even access the 12v

It’s insane that the converter don’t kick in when car is connected and charging🤯🤯🤯

We don’t need 12V anymore - a french car dealer modified my eSoul 64 kWh to get the Energy from the big batterie instead.😮 Bevore, We had 4 new 12V and stranded 7 times in 4 Years because of empty 12V. We did not dare to activate cabin light or close and open the door to often eg while camping. Last 12V in November- breakdown in Mai , during our Holidays in france although i put the car in Utility mode for a few minutes zu charge 12 V

This „Trick“ also works on an i3. Against all the others the i3 has no Vampire loss of Energy. If you never change the 12V Battery on a Tesla, you will have the same. Remember IKEA Oslo, in the middle of the Night ? It was a Tesla, when you need the Yellow Man ! Cheers Nick !

My OBD single displays the 12v battery voltage using Car Scanner. I had my first battery problem this weekend. When camping with my EV6I left the boot/trunk open for a few hours. The car wouldn't start and the screen and interior lights were flashing. Fortunately I was prepared with a jump start battery which worked perfectly. Check out EV Odyssey.

Great tip thanks. 2013 LEAF

I'm impressed by the 12V battery information given by the app. Even Tesla doesn't provide this information thus far.

So, in Thailand many EVs will not have heater, because it is not needed? Fossils have it as standard i guess? Teslas probably will have it too if they sell it officially? It should also be mentioned if you have low 12V battery in a Tesla, don't drive it below 10%, because then the 12V isn't charged any more. The EV ambassador has a very cool video about ít.

See, this is why all EVs should have some solar panels. Not to charge the main traction battery but to charge the 12V battery and run the electronics, and keep the main battery from being drained just to keep the car "alive" while it isn't in active use. We should be able to park any EV for six months and come back to everything still working perfectly instead of a dead car. Any fossil car can do this no problem with a bit of fuel stabilizer in the tank and a solar battery maintainer.

I enabled the “Use cellphone As A Key” feature in my Ford Mach E. With the car parked in my garage. While I worked on projects (my cell phone in my pocket) the Mach E would “wake up” many times as I entered the garage or stayed working in the garage. When I drive to the airport (SLOW traffic about 1 hour) the 12v system failed (red battery icon. After a few tries and me verbally threatening to post the 12v failure on FB and Twitter the car suddenly was able to start. The problem has not reoccurred since I turned off the “cellphone as Key” feature. The Mack E no longer lights up to greet me however.

Get a solar trickle charger, place it on the dash and hook it up to the 12 volt battery and it will maintain the voltage when the car is parked for long periods. I use one in my van all the time and it works well as I only use the van on the weekends. When not used, it is stuffed into the driver side door pocket. 10 watt panel is usually good enough.

Just curious about the size of the 12V battery in the MG. Is it a typical 45AH like in a normal mid-size gas car? Because I reckon a small motorbike-size automotive battery would do fine if you were ever replacing it. As it does not have an engine to start it has a very easy life in an EV, just doing the lights, wipers etc. Car makers are inclined to use Lead-acid stuff for the 12V system to keep down the cost of Li but they are very heavy in weight. You could even use an UltraCapacitor which is cool.

what happened with the steering wheel? was it hurt, because of the bandage?

Have you considered adding a remote battery kill switch (used in old petrol cars having parasitic battery drain)

hi, just came back from holiday 14 days and cannot start my Mgev. shows red and yellow battery sign on dashboard. what shall i do next ?

What type of vehicle should I choose between electric/petrol/diesel varient on 2020 ?

That's not why you *need* a 12V battery. The 400-800V of the high voltage battery pack can be fairly easily stepped down to provide a nominal 12V supply for anything that needs it. In fact, every EV has such a converter in it to provide such a nominal 12V supply (more likely somewhere round 14.5V) to both run the accessories while the ignition is on and also recharge the 12V battery. The reason you *need* a 12V battery or some other low power source of energy is the main contactor. When not in use, the high voltage battery is completely isolated from everything by the main contactor, which is an electrically controlled switch. Something needs to provide the power to close the main contactor for both system operation (eg. driving, climate control, LV battery charging, utility mode, etc) and for charging. This is the reason that you *need* a 12V battery. Without that requirement it would be easier and cheaper to just use the buck converter that provides your stepped-down nominal 12V supply directly from the traction battery. You would avoid the cost of the battery as well as the cost of developing and maintaining 12V charging logic in the car's systems.

Hazard indicators and interior lights will work while key off to drain battery 🔋👍

Is this "rope" on the steering wheel the standard equipment of MG's cars?

The warning. Light. I kept it on for 1h, and my 12v is dead

BMW I3 is the one of the worst EV on this planet, unintuitive interior, poor range, weird door design, but this is the best car I ever tested. The best thing is of course, this is EV.

Hi Bjørn! I have a question for you. You say in the video that in Kona i need to enable it. The user manual says: "The Aux. Battery Saver+ function will be ON when the vehicle is delivered." Is there something else what i need to enable? Here in Hungary are several owners whom 12V battery last just a year. :(

This trick SHOULD work on any EV that supports preconditioning. But so should leaving it plugged into the charger, or doing anything else that leaves the HV contractors closed so high voltage can flow in or out of the HV battery. But I wasn't born yesterday so I wouldn't put it past SOME manufacturer out there to do something stupid because it saves a tenth of a penny.

What about lithium-ion 12v battery? They last much longer than lead. And they are lighter so you get more range.

Wiring the 400VDC around in the car and replacing the 12V would be super expensive as safety requirement of a 12V system and a 400V system is two different worlds. The car would be somewhere from 2 to 5 times as expensive to manufacture. (if 400V lights, wiper motor, fan motor, windows motors ++ have existed)

so normally when the 12v battery is still good, how many volts the DC-DC converter out put to charge the 12v battery ? can you check it at the 12v batt terminals when the vehicle is running.

I believe some of those running out on 12 V, do many short trips, and don't care to plug in every time, and heating/cooling drain more from 12 V than the DC-DC will deliver to charge.

The car name is Doraemon! How cute

My only guess why the batt showed 14 volts when you used the AC us thee HV batt had to enegize to run the AC unit when it did it boosted the 12 v batt?

Level 1 charging also will charge the 12 volt battery in some cars.

Good work around (I used scheduled preconditioning to get past the intial Mach E 12V problems), but note that regular preconditioning can be over 5 kWh per session, while a 12V trickle/maintainer is some Wh. If you are balancing an annual solar array budget, used regularly, this plan can do in your solar credits.

My 2017 Chevrolet Volt seems to manage the 12V just like my 2018 Model 3 as well. Phew!

My FF hobby / spare car and bike I keep the battery on trickle charge, if I had a electric car Id'e hook up the 12 volt battery for charge when I connected the main charger

Can someone please tell me if you can sit in the car with the aircon running while you are charging the car.

It should be possible to have a dc/dc converter with high enough current capacity to supply 12 V and eliminate the 12 V batter. This will reduce weight considerably.

Top: Never shut your car when you are sitting/ chilling/ waiting in the car for longer than 5 minutes. Otherwise it will use your small 12 volt battery, of course it will rapidly drain the battery. If your EV car is on it will use normally the bigger high voltage batterij. Simpel as that!

Can we add 2nd auxiliary battery parallel to 1st battery 12v?????

So I have to start the car and turn on ac high?

turn your headlights on to drain the 12v?

Why is there only an app in Thailand for the MG?

I hope they bring the app to Europe/UK.

Unfortunately, the UK model will not have to app support. Nissan LEAF I seem to remember used to have an option on the 24 and 30kWh models for a small Solar Panel integrated into the rear spoiler above the rear window. for the purpose of trickle charging the 12V battery. Maybe it is possible to either fit something similar to the MG or at least use one of those aftermarket 12v solar panels sold to trickle charge boat batteries when on their moorings - it could be laid on the top of the dash while the MG is parked and plugged into a permanent live 12v outlet if the MG has one. Has anyone tried this?

Millennium Falcon for the 12v win 😊

As far as I'm aware, UK spec MGs don't have preheat

Can you just get a small 12v solar panel and plug it into a 12v outlet? Or is the 12v outlet not live when the car is off. Or could you just run the lead straight to the 12v battery.

Pls Bjorn, can you help me. I have the same MG charger overseas and need a replacement RFID card. The local dealer doesn’t know where to get replacements because the MG chargers were given out for free. Please could you tell if your dealer in Thailand could create a RFID card for me if I gave them the serial number. Of course will pay for shipping etc. Thank you. P.s. I bought the MG because of you.

Doh - no app and preconditioning for MG ZS EV in the UK 😞

So does your ZS also have a open steeringcollum just like here in The Netherlands!??

So the point is, dont use 12V stuff when the car isn't on or you'll drain the 12V battery.

My 2023 LEAF has low12v voltage problems 3 times a week. Its annoying as heck. Nissan dealer is just clueless and tells me to plug it in..... uhg.

Ioniq automatically recharges the 12V battery from the big one.

Good information mate

Hello Bjørn! The 12v battery in my three month old Thai car went as dead as a dodo over the weekend. The MG mechanics arrived at my house with a replacement battery. They told me the reason it went flat was because I hadn't logged out of the app. They said I should always log out. First time I've heard this. What do you think?

Not a great test. 13v or higher means the 12v battery is being charged. You could put a multi meter on the 12v battery or drain off directly using some external load. As with the leaf i expect the car monitors and if the 12v battery drops below 11.8v it will activate the charging DC-DC system

Maybe this is the problem on the ID3. And hopefully can be fixed with an update in Q1 2021.

Wrong! Just noticed your explanation for 12v Battery, ALL EVs use one because when car is switched off the traction battery is disconnected! Would you leave 400-800 volts permanently live? Of course not, so in an EV when you switch it on some of the clonks you hear are relays kicking in and connecting the traction battery to the motors! That is the main reason a low 12v battery causes so many issues in an EV.

you would think if the main battery can be converted to charge the 12 volt it could use the same system to just run the 12 volt things.

Show us how to enable the Kona's 12V charging, please.

voltage doenst say everything, is the current whats is bad.

Can the charging be stopped remotely in the Thai version of the MG ZS EV..?

Please visit India and check out the E²O EV!

Thanks for that info, I wondered how the 12 volt system was charged, I would like an EV, but I normally store my car for six months of the year during the winter, and put a trickle charger on the 12 volt battery, this often fails and I end up buying a new battery, this is a petrol car, I have tried asking Renault about the Zoe, but just got a quote from the user manual about not using the car below 25 degrees, which had nothing to do with my question, which is how can I leave an EV untended for six months, and with no Internet connection, am I asking the impossible, I think I am?

What if the 12v becomes flat?

Still don't get why you need a 12V battery. If you have a DC-DC converter to charge the battery, why not use it to run 12V fans, lights etc directly instead. Presumably the converter delivers the 12Vs needed.

Varför lägger du aldrig upp några videos på thai-kanalen på thai? Vill visa mina thaivänner :) /Cristian i Chaiyaphum

Hi Bjørn, have 2015 model S and am on my third 12volt battery. The tech replacing the latest battery said he will try to adjust some algorithm. It is not a daily drive. Driving it less and less as I work fewer jobs and getting closer to retirement. Thinking about some kind of trickle charge system. I hate the idea of selling it!

Unfortunately this can also happen with the Ioniq 38kwh despite having the battery saver on. This system only checks the 12v every 3 days or so, so in the meanwhile it can run empty. Happened to me only once so far, road side assistance came and measured 4,5 Volts (no, not a typo, really that low). Both they and the dealer could not find the cause, so that gave me a really comfortable feeling… although they did mention that (fast) charging would run the 12 volt battery dry? Made no sense to me, also I only fast charge this car once a year or so on longer trips. I now have a 12-24 volt charge meter that goes in your cigarette lighter and is reads anywhere between 11.8 to 12.4 when the car is only on battery (press on once without brake). While driving it goes to 14.5 to 15 so that is working. I will try this trick with the preheating from the app, it runs for max 15 minutes in the Ioniq. Voltage this morning was 12.0. Will post the results here later.

Good Shit!

For what safety will the AC turn off after 10 minutes!? I hope you can turn that superstitious bullshit off :( (I'm assuming it's a "fan death" thing)

👍

Didn't teslabjørn once have a dead Tesla because the 12v battery died?

thailand in no way is norway, it's hot, battery won't die, relax.

Tell me price for this car