Tech Primer: Why 12-Volt Batteries in Electric Cars Get Sick -- And How To Keep Yours Healthy

[@mahtin]

I came home to a dead EV and of all the videos I perused, this five year old beauty finally explains the “why” vs saying “it happens”. The answer was chemistry and now it all makes sense. Thank you!

[@stevestier7732]

This is a truly informative video. I have never heard such a complete explaination of my Leaf's auxiliary power system. Well done.

[@MrLongraphics]

Why don’t electric car manufacturers design their dashboards showing the 12v battery status? I mean.....would you buy a mobile phone that doesn’t show whether your battery is full or empty? Or a petrol or diesel car without a fuel gauge? I have 6 years experience of driving electric cars. First our Kia Soul (2016). Twice the 12v battery went flat and called out the emergency services. Same for our latest Hyundai Kona (2019), again twice with a totally dead battery! It’s not rocket science is it? Our Kona is packet with state of the art equipment such as adaptive cruise control and auto dimming headlights, But nothing to show how much juice is left in the 12v battery! This really needs addressing urgently.

[@richardwilde1348]

Guess they've got to leave something for the mechanics to fix. Seems to be the only thing that goes wrong with EVs - though quite consistently!

[@BastienVide]

You can't easily guess the capacity of a 12v battery. It's not like an lithium battery. But, some cars (Volkswagen for instance) are displaying if any charging error or voltage drops occurs on the 12v battery (on all their recent EV, PHEV or ICE cars)

[@zqpcydbfoqbdiehdj]

True. It’d be easier

[@zqpcydbfoqbdiehdj]

@@richardwilde1348 to then scam you with lies. Yeah, so innovative. Plus the money doesn’t go straight to them!

[@dansizemore6319]

What a great idea! My Nissan LEAF (piece of shit) told me via a dash board message, on the way home, that once I turned the car off it would not power on! Not helpful unless you are driving to buy a new one. Indeed, the car has been in my driveway for 2 days. I am trying to decide whether to get a new battery (this would be the 2nd replacement) or just donate the thing to charity--I truly hate it!

[@mikeiimura]

Well Done Nikki. I have a 2012 RAV4 EV and it is also very hard on the 12V battery. A significant number of people have had the 12V replaced under the 3yr/36k warranty. The reason is that the RAV4 EV does not wake up and recharge the 12V when it gets low like a Leaf or a Tesla does. Even when new, if you leave one for 4-6 weeks, it will drain the 12V due to the telematics, SmartKey, and other parasitic loads. Dealers didn't know this when they were new on the lot, so many of the batteries in those cars had their lives shortened by being drained flat. I proactively replaced mine at about 3.5 years of ownership with a Bosch Platinum AGM battery. I went up a size from Group 35 to Group 24F since it fits the full size of the battery tray, had a larger Amp-Hour capacity and was only $1 more. The same battery is also available with Exide branding.

[@StephenEvans-m8z]

I had this problem with my Kia Soul EV just 2 days ago. Worth mentioning that when the 12v battery dies, you get all sorts of problem like door locks wont open so you cant get to open the bonnet unless you have a manual emergency key in the key fob. Luckily I did, so new battery on its way, plus judicious use of battery conditioner from now on. Thank you for an informative video.

[@michaelmaffucci1446]

Thank you for your public service. This information helped me better understand and trust my ev. Just completed my first 3year battery replacement. Helping people understand and remedy problems that can be perceived to be much larger is awesome. Thanks

[@SheilaFeatherstone]

This is fab. I had the 'dead car' problem this week , 80% charged but key would not work. The best the Kia dealers could suggest was recover it to them to take a look a week later. Finally the RAC diagnosed it straight away - new 12v battery - all good. But I don't want a repeat, this was really helpful, thank you

[@GrayRaceCat]

Nikki, great content and presentation! (as usual) As a service tech who works on both hybrid and ICE vehicles maybe I can shed some light. I agree that the Tesla is the exception to the rule in that it is in constant contact with the "Mother Ship" for updates and is never truly "off". As such it should be able to keep the Auxiliary 12v battery charged while not in use. Other vehicles these days (Electric, Hybrid) disable the traction battery and go into a "stand-by" mode and need the 12v battery to activate the main relays for the traction battery(Electrics & Hybrids.). as well as maintain the user presets and preferences for Radio, Navigation, Climate System, and adaptation for the Fuel Management and Transmission Systems(Hybrids). The choice of "Flooded Lead Acid" your standard car battery, or AGM "Absorbed Glass Mat" depends on the location in the car. Lead Acid batteries emit Hydrogen Sulfide gas (a caustic and explosive gas) while charging and cannot be located in an enclosed space such as the trunk or passenger compartment. AGM batteries do not emit gasses while charging and can be located anywhere. For example the Prius is AGM and is located in the trunk, the RAV4 and Highlander are Flooded Lead Acid and in the engine bay. Flooded Lead Acid, AGM, and the various Lithium Ion battery types all have different charging requirements and generally can't be used as "drop-in" replacements for each other without the risk of damage to the battery. Reducing the service life of the battery, and in the case of Lithium Ion batteries, possible catastrophic damage to the battery and vehicle.

[@alexgray552]

There are 'drop-in' LiPO4 replacements for car batteries, but they cost £500-£1000 depending on capacity, so no surprise they aren't fitted as standard! www.qualitysource.co.uk/products/novel-series-12v-100ah

[@DennisMathias]

In my Tesla that battery is inaccessible except in a shop. However, the 12v battery will sip off of the main battery. Remember, many of the electronics need to be powered up all the time. Otherwise you would not be able to unlock it or access it by your phone. And its sensors look for battery pack heat or cold so it can do its thermal transfer when needed. Another point is the battery in electrics are deep cycle and not a starting battery like in a car. They are meant to be cycled for long periods and the reason your battery was dropping in voltage was that there was SOMETHING drawing current and discharging the battery. The only way to make sure this is happening is to disconnect one to the terminals of the battery and measure the voltage with absolutely no load. It should be pretty steady even if it is crappy. And while you're at it measure the current being drawn with your ammeter..just for the record. The 12v batteries in electrics are invariably AGM types. (You can look that one up) BTW, I had to have my 12 battery replaced just last week. Tesla monitors the voltage at the mothership and then sets a flag for replacement SOON as it has any excursions below 12 volts. Very conservative and I drove it for a couple of weeks like this before the ranger came out and replaced it. They are smaller than a regular car battery by about half. There you go! Good show and great presentation though.

[@simoncanfer5030]

After reading comments on Speakev, I replaced the 12V in my Leaf when I bought it at 3 years old. £45 is cheap for peace of mind! Chances are it had gone flat at some point in the past. ALDI do a cheap 12V maintainer and I use that each month. Also keep an eye on the voltage via a voltmeter on the accessory socket (cig lighter). Start the car in accessory mode (without foot on the brake) and read the real battery voltage.

[@MrsGrey]

Thank you! My Kona electric was totally dead today and I've finally got it in trickle charge. But the explanation you give us is super-clear and I'm going to get a checker and be more 12v aware! 😊

[@riceburner4747]

Do u hardly drive it &/or have low mileage? I have trouble on my Gen4 Prius. I installed a "mouse blocker" under my hood & don't drive it much & it discharges my 12v constantly. Computer & electronic accessories ALSO drain them. So I'm going to check mine every two weeks. My battery is now 4yrs old so average life of them is 5yrs. Others say they've had theirs for 7yrs or more, but they drive them a lot more, which is BETTER for batteries. I used to work for a battery company.

[@thalesofmiletus2966]

@@riceburner4747 my Kona EV has done 26,000 miles in two years and is used every day. Most journeys are 50 miles+. The battery still died.

[@richfrederick2167]

My 2013 Leaf needs a new 12 volt battery too. It lasted for 6 years which is typical, thanks for the video and reminder to use a battery tender. I also learned that if you run out of power with the main battery and put your flashers on while waiting for a flat bed to arrive and the 12 volt dies, you cannot get the car in neutral unless you put jumpers or a portable charger on the 12 volt battery.

[@jennlmorrow]

My 2016 Nissan Leaf wouldn't start this week when it was -26 F. The error message eventually led me to some good info and your video. Threw a charger on it and saved it from freezing solid. Thank you for saving me an expensive tow and visit to the dealer! I just ordered a plug-in volt tester and a tender. Great video. I drive lots of short trips so I am really hard on that 12v. Surprised this didn''t happen to me sooner! Wish the manual had explained *why* driving less than a mile at a time was a problem, it's easily solved if one knows the issue!

[@billcawthorne3114]

I enjoy your videos. This one struck home with me. This weekend I thought its been six years since we bought the Leaf. With only a water pump failure, I've gotten used to ignoring maintenance. So checking the twelve volt battery water level and voltage came to mind. The battery is holding twelve volts and a nominal water level. That is six years here in the Arizona desert. Time to replace anyway. Love the Leaf. Hope it is the last car I need to buy.

[@RetroDawn]

If it checks out ok, it should be fine for a while longer. If you're going to replace it no matter what, just based on age, why bother checking it? Or, perhaps I misunderstood what you meant by, "Time to replace anyway."

[@JeffSongster]

So far so good with our 12v battery. We got SL models that trickle charge themselves when in direct sun off the tiny solar panel in the rear spoiler. Our 2013 is the one I am watching in terms of battery age. Thanks for the informative video! We actually needed a trickle charger for our ICE car since it hardly gets used since we got our LEAFs.

[@XY_Dude]

I say... Good show! I never heard of sulfating due to insufficient high-draw events. Thanks.

[@melenriquez8985]

2 solutions. 1. get a 12-volt desulfator if you are using a SLA batt. Desulfate at least 2x a month if the battery has been used about 6 months or so. 2. The better solution is to get a lithium-ion 12-volt set Even a 12aH wll be good enough for this application of starting up. Like your main lithium batts, they will last years too. Nothing to worry anymore of desulfating or maintaining it. A lithium 12-volt 12ah, will cost about U$50-80 depending where you get it. Just make sure that it comes with it's own built in BMS.

[@gregripp]

Should be lighter too.

[@otooleniall]

I park my hybrid outside and have a little solar trickle charger on it. The original battery is still good after nearly 9 years. Some Leafs have the little solar panel on the rear spoiler for that reason. But obviously doesn't work well in garages or car ports.

[@richardwilde1348]

I think the rear solar is just to run the air conditioner or something similar

[@otooleniall]

@@richardwilde1348 Prius had a solar roof at one stage to run the fan but Leaf one is tiny and only tops up the 12volt.

[@richardwilde1348]

Ah okay, must have misremembered what it does. Could do with one like that, our Leaf is having 12v issues.

[@NLR759]

The 12 volt battery in my 2018 Kia Soul EV just died on me this week, and it's only three years old. I had it inspected by a service repair shop, and they told me it could not be recharged, it was completely dead. I was really surprised my battery would be completely dead, after only 18,800kms driven over the last three years! Thanks for the explanation.

[@HeinzP100]

Great video. I would never have guessed that a standard 12V battery would be needed in an electric car. Makes perfect sense. Although, I would have thought the battery would get a few more years between failures than the 4 you've gotten.

[@TheChadWork2001]

Good video, thanks Nikki.

[@transportevolved]

If you’re trying to say something, say it.

[@TheChadWork2001]

@@transportevolved Sorry Nikki, that had nothing to do with your video or channel. I was replying to another comment on another channel and must have posted it on your channel inadvertently. You were kind. Thanks.

[@bobprince1472]

It sounds like the battery sulphates because it has too low a current load. I had this problem with a 10yr old ICE car battery. I bought an 8amp Pulse Repair Battery Charger which completely fixed the problem of the battery not holding charge in the winter. It cost approx £26 and was cheaper than a new battery. It takes about 12hrs in repair mode with the battery disconnected from the car. The repair lasted until I sold the car and bought an EV (2yrs later). Magic! Looks like I might be using it again...

[@scavanger1000]

Surprisingly my bolt's OEM battery has, as of now lasted 3.5 years without any signs of issues, I got a cheap battery tester and it still reads as good too, tempted to replace it with a lithium battery from ohmmu just to be safe. I recently got a dashcam and hardwired it so I know at least it hasn't dropped below 11.6 volts at all even when it's not plugged in for 10+ hours

[@jamesalles139]

Yes. *THIS.* Thanks for sharing your knowledge. It doesn't hurt to do a maintenance full-charge on any vehicle, once a month (whether it needs it or not ;)

[@John-km2uw]

Good training video for potential EV buyers and current Nissan Leaf owners. This video is not excessively technical, rather, easy to understand and apply to the Nissan Leaf at home in your driveway. Notice that she mentions EVs with the 12 volt battery in the trunk. If that is an interest to you, I suggest that the audience look for information about the 12 volt battery in the Chevrolet Volt version 2 and the Ford C-Max Energi. They're not as easy to get to for service as is with the Nissan Leaf. Thanks for lesson Nikki, and thank you for the Transport Evolved website as well.

[@tomy2t0ne3]

Great video! I had some weirdness 9months with the EV system light coming on so I went ahead and changed my original 2013 Nissan leaf battery so I wouldn't' be stuck in the cold. 9 months later I started seeing the EV system warning light coming on again and I thought it was my charger. Last night my car was dead, I first thought it was the fob and went and grabbed my other fob with the same results. I changed the fob battery "just in case" , with no results. I put the battery on the charger today and I went back out to check and an hour later and it said the battery was full. I checked the voltage and it showed 10 volts! Never rule out a bad new battery!!

[@jooky87]

Smartest car presenter in the business.

[@marvinsamuels1237]

Very informative Nikki. I watched his video as I collected my brand new Ioniq EV last Thursday lunch time, parked it up for the rest of the and came out Friday morning to find the 12v battery was flat. ‘Jump started’ and then put a trickle charger on it for 4 hours and all seemed to be well… until this morning when it was flat again. Currently waiting for a call back from my local Hyundai dealer.

[@graememudie7921]

You would think that they could tap 12v off the main battery rather than having the additional weight of an additional 12v battery. You are absolutely correct with what your saying about a “normal” car battery. So one must ask why are they using this type of battery? Surely a leisure battery would be more appropriate.

[@johnkeepin7527]

Around 4:45, the point is well made about relatively low max currant and it’s effects. Maybe the battery lifecycle is reduced that way. I haven’t had a fault with the 12V in a hybrid yet, but I’ve had a major one with an old ICE car, that flattened it’s battery overnight on account of a software fault in one of the built in devices. There were thousands of cars affected by that, and there was a firmware update under warranty. Also, another one had it’s 12V battery replaced by the dealer ‘cos it didn’t pass it’s servicing tests. There are products available that can be carried on board easily for the equivalent of ‘jump starting’. I have one which has a 9 Ah 12 V Li ion battery, capable of delivering enough to start a typical diesel or petrol car, and it’s easy for a hybrid as all that it has to do is to switch on the high voltage dc battery power. Toyota hybrids do not use the 12V to start the engine - it’s the high voltage one that does that, but you need the 12V to switch on the high voltage by energising the contact relays, and once it’s on it should charge the 12V via it’s inverters/converters as you go along.

[@Hitstirrer]

There is definitely a problem with the Leaf's 12v system. Far too many cars have such issues. And almost all bizarre behaviour glitches are caused by low voltage there. It seems to be caused by the way the 12v battery is topped up by the main traction battery. That can allow the 12v to not be charged as we are used to in an ICE by a permanent alternator charge when driving. I have given up trying to nail down the cause. I now accept it as a fact of life with a Leaf. I now just put the 12v battery on a long charge once a month using a 'smart' charger. They don't just charge up like a 'dumb' charger but analyse what is required and charge at whatever rate is required - and then after that go into a conditioning routine to repair any sulphidation of the cells that has occurred. As part of the monthly tyre kicking and screen wash filling such preventative maintenance is highly recommended.

[@donniecarrascosr.9912]

Blimey , I Absolutely enjoy your spot on advice, Rather, I enjoy your calming accident which I am accustomed to. It brings back memories of the boys back home. have a great day, bird, all the best Luv.

[@aatheus]

I've definitely encountered this in Gen 1 LEAFs in the UK. There was one in a rental fleet in Milton Keynes. It had sat around for a couple of weeks, and the 12v battery was hovering around the 8v mark. The main console did some funky things when I tried to turn it on!

[@tedschroeders5289]

This is the most informative video I've seen on this topic by far. Thank you very much for posting it. I don't own an EV nor do I want one, but they do occasionally come into my shop so it's good to be informed in that regard. Thanks again.

[@transportevolved]

Glad it was helpful! ^Kate

[@God-of-our-own-understanding]

My 2011's died a death last summer. Ignored a "Problem with the Charging System" light for weeks until it all gave up on me. Had to have it jump started and flat towed to the dealership for a very expensive visit. Thankfully the replaced the drive battery under warranty but had to pay for a new drive battery cooling system and the new dc battery. Still cheaper to own and operate than any ice vehicle I've owned!

[@cpufreak101]

don't forget though, you lucked out by not having to pay several thousand for the new drive battery

[@mujkocka]

So nice to see a woman in a car channel! And sadly I had the 12volt battery problem sadly on the road

[@impuls60]

When you go below 75% discharge state the sulfation process starts! So it pays to have the battery topped up. Somebody mentioned super caps but they would only store about 1/8 or less than the energy in a lead acid battery. I have 6 of them in series and parallel to my lead acid battery in my Rav4. Makes starting super easy in cold weather here in Norway :) For a direct replacement battery look into EFB batteries or GEL batteries for better longevity.

[@avidviewer1]

Great video. Really helpful. You've got another extremely grateful UK subscriber!

[@LoanwordEggcorn]

If your 12V battery got down to 5 Volts then it's highly damaged and you should replace it. Deep discharge in Lead acid batteries is very damaging to them. As a result of the damage, they lose a lot of capacity and life. I've never gotten more than about 4 years of calendar life from a Lead acid battery. I do have a battery tender on current batteries now though, so it may help. As others have mentioned, the Optima batteries are excellent. We put one in our RAV4 EV and it's working well. Any AGM (absorbtive glass mat) Lead acid battery, including the Optima, will be better than a standard flooded battery.

[@beryleeles6447]

Hello, I have a problem with my Renault Zoe. The 12 volt battery has been replaced by a garage but they did not have the equiptment to reset the computor to get rid of the warning sign and the slowing down to protection mode. We found a Renault garage who re set it and checked it for faults. I got it back yesterday and it drove home fine. Today the problem is back again. the Renault garage need to see it again but think it may have been fitted with the wrong 12 volt battery. It was supposed to be the official battery. On the invoice it says S3002 BOSCH S3 BATTERY. Do you by chance happent o know if this is the battery that should be used for a 2016 Renault Zoe?

[@LoanwordEggcorn]

@@beryleeles6447 I am not an expert on Renault Zoes, but based on Google searches, it looks like the standard battery in a Renault Zoe is a 52 Amp-hour Yuasa YBX3012, and the Bosch S3002 is 45 Amp-hour. If so, then it is slightly undersized. It's a bad idea to use an undersized battery, especially in an EV, which tends to have a small battery originally. (Going even smaller than the small standard battery is not a good idea.) I would strongly recommend to replace it with a 52 Amp-hour or larger 12V battery. Please find a (different) repair shop that understands why this is important. Here's one reference: www.gogreenautos.co.uk/how-tos/renault-zoe-replacing-12v-battery P.S. I would also recommend checking with the Renault Zoe community for more advice. I'm sure there are many Zoe drivers who know more about the specific cars than I do.

[@RetroDawn]

@@LoanwordEggcorn Thanks for your advice, which is applicable to all EVs!

[@nigelcharles511]

Like others we have had 12v failure problems with our Kia. It has failed three times in 2.5yrs. Each time the failure was so bad that we had to resort to manual unlocking just to get into the car to release the bonnet. After the first time I bought a battery monitor which displays as an app on my phone using bluetooth. It also has the added advantage that it shows a voltage history. In our case on the latest failure it showed that the voltage had been jumping between 7v and 19v, not good! This happened on a replacement battery which was only 4 months old. The car is going back yet again to the dealer. This time, due to the monitor, I will be able to show that this is not a battery problem. More likely it is an intermittent failure of the DC-DC converter.

[@timotion7]

Nice video. One way OEMs could solve this is to add a DC/DC (HV/12V) that will always be on and allow the lead acid battery to be charged from the high voltage battery and provide all the sleep current needed for the electronics. Then the main DC/DC when the relays are closed will provide the power needed when the car is active.

[@svendholme3627]

I would think that a AGM deep discharge battery would be a better fit for this application since there is no heavy starting current required.

[@gregripp]

My 2016 VW e-Golf has a Varta 68Ah AGM battery. Nice to have a low maintenance 'starter' battery.

[@victor070]

Very good video. Very clear explanations. Came here after my 12v battery on my 2017 hyundai sonata hybrid died

[@ianwildman164]

This video is awesome! So much information communicated so clearly!

[@brettjohnson6807]

I have found jumpstarting other peoples cars from our Bolt has seemed to pull enough current to at least keep the battery happier. ours was still healthy when it was over five years old, replaced it this Fall just to be safe. Great video!

[@KaceyGreen]

Yes, this has happened to me, my Prius, both Civic Hybrids, both Volts, and Tesla Model S had one battery their whole service with me even though the first Civic Hybrid and the Model S "needed" new traction batteries. However, my current Tesla Model X P100D needed a new 12-volt after just 1 year and 1 month. Thankfully unlike this leaf, it gave plenty of warning (Tesla service appointments don't come quickly.) One quirk I noticed was an outright refusal to do any type of Summon as seen in a video I posted this week. Even though all other functions continued to operate, close to the end of the week with the message on the display and not Summoning it started to turn functions off while it sat for more than a few minutes, everything but the self-opening driver's door and the glass breakage sensor would power down including my aftermarket dashcam! Twice it even powered down the LTE modem! I'm not sure how long you get after the warning but it was a bit stressful waiting on the mobile technician's appointment. Yes I could have changed it myself but Tesla considered it a warranty item, and now that I've seen the tech do it, it was a bit more involved than I had anticipated because of the battery's hold-down equipment.

[@davidhess6593]

Having similar problems today. Thanks for the info. Will check the distilled water levels tomorrow and try charging the 12v battery. If that works I'll be forever in your debt!

[@watcher24601]

Going through the older videos I found this gem. Wish I new this last winter with my 2nd gen Prius. Car hadn't been used for approx 10 days (It's was just quicker to cycle to work) so come Friday night when I wanted to see family I couldn't unlock the car or do anything. The main battery had at least 70% power that I couldn't access because the 12v battery was totally dead. Ended up calling the AA and looking like I was trying to steal the car - only the driver door unlocks with the little key in the fob, and the battery is under the boot!

[@jenniferkeller680]

This is a great video! Thanks for explaining the technically aspect of what's going on.

[@StealthYoshi33]

This is a frustrating weakness that EV makers need to innovate on. I will gladly pay an extra $500 on an EV for an optional long-life Li-ION 12V battery/supercap or some GOOD solution to be in there from the factory and warranted with the rest of the car.

[@LoanwordEggcorn]

A better battery probably isn't needed, though there's not much reason other than added cost that EVs can't use AGM or Lithium batteries for the 12V. What's needed is better (smarter) battery electronics for the 12V. It's ironic that EVs don't have smarter 12V charger electronics, given the amount of effort placed keeping the main traction pack in good condition.

[@gzcwnk]

Actually lifepo4 for 12volt. Its safer, is better matched to 12volt and they are available for cars. eg www.aliexpress.com/item/4000012901429.html

[@JustWasted3HoursHere]

@@gzcwnk Yep, this guy has a Fiat 500e EV and he replaced his and has had no problem for two years: kzbin.info/www/bejne/jpCTnXmkbr55hMk Typical LiFePo4 replacement should last 10 years or more.

[@george6484]

Thanks for an excellent solution and explanation!

[@grandmomcrafts]

My bmw i3 battery just died yesterday. Getting a new one. I love my car,...wouldn’t trade it for anything. Thanks for this vid!

[@kenneyorr7026]

Mine did also last month bmw I3 died with windows down had to get it towed 2015 Giga factory waranty expired 4 mo ago cost me $535 to have 12 v bat replaced did even know it had a 12 volt.

[@telfordlive]

Great presentation and explanation. Thank you.

[@GermanLibertarian]

Great information! Thanks for uploading!

[@scavanger1000]

Surprisingly I haven't had any issues with my bolt, I've had it for 3.5 years and the battery still tests good

[@thomasboos2470]

A battery desulfator might be a solution, its sending very short high (20V) pulses into the battery to crack the crystal around the lead plates and its build in permanently

[@zurab1977]

I think I accidentally discovered a hack. My 2020 Kia Niro EV would not start because of low voltage. There was no one around to jump start my car but the necessity being a mother of the invention, I decided to go into my Kia phone application and turn on the remote climate control. It activated my air conditioning system and also charged my tiny 12 volt battery. This hack will probably not work if your battery is completely dead.

[@boomchaka7762]

Lovely! Super informative. Thank you so much!

[@FFVoyager]

Do the cheap car cigarette socket voltage meters work in Leafs? They are a simple way of watching the battery level on regular cars.

[@richardwallinger1683]

Thanks for another super video .. my 2011 Nissan LEAF 12 volt lead acid battery is showing 11 . something volts What I noticed was that the electric windows were getting sluggish with the brake lights on . Some silicon cockpit spray on the window channels improved things slightly. a trickle charge for a few hours made a slight improvement. Looking into the battery innards with the screw tops removed indicated one cell was unhappy with the separator's all buckled and gassing a tiny bit ..It is continuing to START the car but after 7 plus years I think a replacement 12 volt is required. Just to be on the safe side .Would a caravan battery be better or maybe a li ion 12 volt .

[@samanmudannayaka9604]

I knew this but didn't bother to even open the bonnet of my Kona ev since I purchased 2 weeks ago and comletely forgot about this 12V battery. This thought me a lesson and got stock without being able to start. I had to borrow a jump lead and got out of the situation which could have easily been avoided if I had seen this video first.

[@katherandefy]

Yes just bought a 2013 Leaf and expensive repairs are ongoing related to the 12v battery.

[@Turtytreeandaturd]

Excellent vlog today..

[@luissaybe]

This is great information, thank you so much

[@roberthuntley1090]

Excellent video - thank you. I've had a few Lexus Hybrids (currently a UX) and understand that the initial start up takes up to 80 amps for a fraction of a second during the start up process. On my car, unlocking the doors starts up the brake booster pump which runs for a second or two as well, before you get to that stage. I've got a voltmeter plugged into the cigarette lighter socket, and have seen the voltage there drop to 10 volts if the car has been idle for a week or two. (As an aside, the voltmeter cost about £3 from Amazon, so worth buying if you want to keep a check on the battery state of charge). On my car, when running its typically at 14.4 volts which means that the battery is being charged, or 12.4 volts which means that it is fully charged. One problem is that the car only charges the battery at 5 amps (to preserve the life of the AGM battery), so it can take a couple of hours driving to fully charge it up. Is that an issue with electric vehicle in general? I'm currently supporting it with a 1.5 amp trickle charge once a week or so, which takes about 8 hours to complete. PS - I had the have the car jump started once because I wasn't doing enough miles during covid lockdown, hence my paranoia about the subject. Luckily my doors unlocked before it died. I'm not sure how you can recover if the doors are locked - break a window to open the bonnet? Any other ideas?

[@roberthuntley1090]

A follow on post. Just noticed (silly me) that the voltage rises to 13.7 volts (with a fully charged battery) when I put the car into Park. My suspicion is that this is deliberate slight overcharge during which the stronger cells gas slightly, and the weaker ones still absorb charge and catch up. I've now taken to using Park more often (at traffic halts), at the end of journey when time isn't pressing and so on.

[@peterhaddad8313]

Yes, very good video thank you. I have a Jag I Pace that ended up with a dead 12 volt battery. I have since been told to lock the car even when it is in the garage because there is otherwise a constant but small drain on the 12 volt battery and if it is not used much every day the battery will slowly die.

[@palisadesbikepatrol8756]

My 2015 Leaf started having brake problems within a few months. The brakes worked fine while driving on the road, but my care creeped forward or backward depending on which gear I put it in initially on startup. The brake pedal collapsed to the floor nearly, and the car was moving. I stopped the car by releasing the brake pedal and pressing again. No sweat. Then things were fine, but occasionally this problem recurred unpredictably. The dealer took two days to recreate the problem in the shop and traced it to low voltage in the 12-volt battery. They replaced it and went through a million resets of everything electrical and gave the car back to me, free of charge for the service. Then later, a EV afficionado told me, yeah, every brake problem with the Leaf involves the 12-volt battery.

[@nils5471]

Really informative video!

[@ColinAICollabs]

Great video, very informative. Thanks! 😊

[@jimbo2629]

My Mitsubishi Outlander Phev is 5 years old. The battery went flat while I was abroad. I managed to unlock the doors. If you keep it in a locked garage think about not locking the car if you are going to leave it unused for a while. I tried charging the battery but that failed. A jump start got it going. I then replaced the battery. I’ve kept the old battery and it has been fully charged and has held the charge. I think that even after 5 years my battery is ok. Perhaps a courtesy light had been left on. Very useful video

[@PeterTeaMiller]

Excellent, clear information. But, what is a "wall-wort"?

[@cfldriven]

2014 Prius still on OEM 12volts. Gotta check the voltage to see if it needs replacing $$$.

[@TheObsessedGardener]

Hey Nikki, you deserve way more subs!!

[@kidlatazul]

From the i3 owner's manual, regarding the 12-volt battery, which BMW calls the "vehicle battery": "Do not use any charging devices. Do not charge the vehicle battery with an external charging device; otherwise, there is a risk of property damage, e. g., to the vehicle's electronics." I own an i3 (love it!)--knowing what I do about the cost of parts for any BMW, especially this one, what the manual says is enough to convince me never to touch the "vehicle battery".

[@dpevjen]

One thing to remember is you might need to top off your battery with some DISTILLED WATER. The battery on my 2011 Leaf is the older style (not maintenance free) battery that uses water.

[@transportevolved]

Totally! I'd forgotten about that, but your'e right. Every flooded lead acid needs some TLC!

[@terrymulcahy4068]

What is a wohl-wart? I had suspicions about my 12 volt battery from the beginning. Checked with service dept., in person and they confirmed that I could use an OEM branded trickle charger. And this I promptly did but lo and behold, the 12 volt battery was just about flat! So now, I put the trickle charger on the 12 volt battery every few days.

[@andrewmuscarella2934]

Nikki - I had an interest life lesion about car batteries back in December of 2013. At the time my 2006 fusion with it's original battery, was 7.5 years old. On a cold day (single digits F) after work I went out and turned the car over and the car wouldn't start. Was turning over fine so I didn't think I had a battery issue, long story short the battery was providing less than 12 volts - the starter motor (and lights) worked fine but the voltage was to low for the computer so the electronic ignition would not function. Expensive less.

[@albertandersen2327]

Well done! Thank you.

[@MegaGasek]

How ironic! A testament to how far we still are on these EVs. Anyway, keep a Noco GB40 with you at all times. I had just changed the batteries on my 2005 Mazda 3 but somehow the battery was being drained. The Noco GB40 jumpstarted my car and I didn't have to call tow. My old 2009 Porsche wouldn't open the frunk so I connected the GB40 to the electrodes on the door and was able to open the frunk. I then went on to jumpstart the car. It will also charge cell phones, tablets and some USB laptops.

[@ritamariekelley4077]

My 12 Volt died a couple of months ago. Should there have been a warning? If so, I didn't see it. Towing was a nightmare as I couldn't get it into neutral, so the tow person literally had to drag it onto the tow truck. Do you know how to get the LEAF into neutral when the battery dies? Love how knowledgeable you are. Great vid!

[@dperreno]

I've had similar problems with my 2010 Ford Escape Hybrid, and I've used the same solution. My 2017 Chevy Volt doesn't seem to suffer from this however. Even so, I just replaced the original battery with a new AGM battery as it is 6 years old and I don't trust it to last all that much longer. One thing to note, most hybrids and EV's specify AGM batteries as they do not suffer from the dendrite growth problem that you described.

[@JimmyBob708]

Genius lady

[@oceanfroggie]

This problem is a hangover from Legacy manufacturers cutting costs by converting ICE models to EVs rather than design an EV from the ground up (ie retain all the ICE 12v electric systems inc lights, cabin electrics, etc). Its totally daft that an EV needs a separate 12v battery from the main DC pack.

[@COSolar6419]

I don't believe there is a single electric vehicle made today that does not have a low voltage auxiliary battery system. That includes Tesla.

[@AnhTrieu90]

Hey Nikki, will you replace the 12v lead-acid with Li-ion? And will it void your warranty if you do?

[@rob_lightbody]

Great, clear explanation. Wouldn't a better quality EFB or AGM battery help?

[@ASC4211L]

Great video

[@PeterStaniforth]

Can you do a standard voltage drop test to find current draw on a Leaf using the fuses like you can on a normal car?

[@JerryMichalski]

Didn't drive our new Leaf for about a month and learned a hard lesson: don't leave your car plugged in to its charging system (in our case, EverCharge). At least that's my best guess for why our Leaf was bricked when we tried to start it. Our insurance called a repair dude, who showed up in a normal car (I was searching for a tow truck). He jumped the Leaf with his portable battery, which allowed it to get running. Then I drove around for an hour, and the 12V appears to have recharged. Just opened a multimeter I bought on Amazon (such a confusing device!) and it shows 12.3V, so the low end of normal from what I can tell. So... why doesn't the Leaf (or LeafSpy) offer any reading of the 12V's health, and why aren't Leaf owners warned this is important? It's like not knowing your new pet has a pacemaker. Dumb! Oh: are y'all still in Portland? Saw from your other video you were on a road trip toward us.

[@ImplyDods]

Hi Nikki, I would suggest buying a smart charger. I have a ctek mx5 which has a 7 stage charger and includes conditioning​ at a higher voltage. It wasn't cheap but well worth the money as it has recovered three batteries from dead and maintains two leisure batteries i have in tip top condition. Just give it a cycle once a month and you should double the life of your batteries.

[@Joe-ud2hb]

Hi Fb - my thoughts too, re smart charger do you leave the battery leads connected when charging it with the ctek

[@BillDeFalcoGFE]

Great Video - Very Useful Information!

[@SuperFredAZ]

Very good explanation of the "why". I was having trouble figuring out why the 12 V. was necessary, i.e. why not just have a 100 Amp dc/dc converter from high voltage to 12 V, but I didn't consider the safety aspects.

[@americanhindi]

My 2012 LEAF SL's 12v battery was dead in mid December 2016. The battery was less than 1 year old. I haven't been driving my LEAF for a while due to charging station installation restriction in my condo. I thought the solar spoiler will continue to keep the 12v battery charged up as it did all year long. I tested the solar spoiler, its working! But during the last few weeks, something must have gone wrong. I suspect that AT&T closing the 2G spectrum must have the TCU (Telematics Communication Unit) which basically an always ON cellphone, must have been continuously searching for network signal and eventually discharged the 12v battery. AT&T website states: "we started to discontinue service on our 2G wireless network as of December 31, 2016". Also, my LEAF's solar spoiler is unable to keep up with the slow drain of the 12v battery of my unused LEAF during the cold season when the sun is low and daylight hours are short. As if that's not enough, the solar spoiler's Plexiglas cover has become faded and a little opaque, probably due to years of UV damage. So I added an additional 12v solar trickle charger ($12 in Harbor Freight www.harborfreight.com/15-watt-solar-battery-charger-68692.html ) on my dashboard facing the windshield. I parked my LEAF facing South so that the solar panel on dashboard gets the most from direct sunlight in the low winter sun. I have used these solar trickle chargers for years for my motorcycle batteries during winters and they did their job very well. Even when these panels are not in direct sunlight, daylight alone was enough to keep my 12v batteries trickle charged and maintained. These have a very low current in milliamps, so there is no risk of overcharging. LEAF's 12v accessory outlet (cigarette lighter socket) disconnects when we turn off the car. So I had to run the wire thought the drivers side door, panel, and under the hood directly to the 12v battery with alligator clamps that come with the solar panel. So far it has been three months since I installed the 2nd solar trickle charger, and the 12v battery of this unused, uncharged LEAF is still functioning. Installation pictures available on Facebook's NJ Nissan LEAF Owners group.

[@Rhaman68]

The battery was probably defective and had a warranty you should have claimed. My 2011 is garaged and last January saw little sunlight, no problems. If there is no sun, the 12 battery gets charged when car is plugged in, as far as I know. No issues in dark winter months and I believe, I did buy the car used, three years old, this is the orginal battery.

[@americanhindi]

I can't plug in because I live in a condo. I charged it once in September to 65% and its been sitting there ever since.

[@bennygustafsson9580]

You can polish the plexiglass cover with ordinary car wax to its former glory.

[@americanhindi]

Thanks for the tip. I will give it a shot.

[@AlvaSudden]

Super helpful. I think I need a new battery in my Chevvy Spark. Liked and Subscribed.

[@azalru]

I saw a third-party Lithium ion 12v battery for Tesla. I would get that to replace the lead acid one.

[@StealthYoshi33]

That would be a good idea, since modern Model S makes it so hard to access the battery*. I wonder if it would void any warranty (or rustle any service shop's jimmies) and make them deny coverage? (*I'm not a Model S owner, I just do my homework, will own a Model 3 someday soon)

[@paulgracey4697]

This problem is the same as I experienced with my Prius hybrid while at the dentists. I was given a jump that enabled me to get to the nearest Toyota dealer where they told me the bad news about the 12V battery. I asked if it was possible to use an Optima spiral wound battery and they said no, they only had the same battery that would fit. About that time I was in need of both lunch and the cash to purchase it. So I left the car and walked across the street where there was both an auto parts chain store, and the ATM I wanted. I decided to check on the veracity of the dealer's service supervisor, and sure enough Optima did make one for the car. I did the Optima replacement myself, and because that AGM type battery uses pure lead which does not tend to sulfate easily, I have had no problems since. The Optima and its kin are what car collectors have used because they do not self-discharge, or sulfate, so they will hold the charge longer, and be ready when that car show comes around each year. I think that eventually either super-capacitors or a combo with lithium will supplant the old lead-acid tecnology for the initialization(not really starting as in cranking-over)of the traction system computers and solenoids. Already on board hybrids and BEV's are the DC-to-DC converters to supply and recharge those IC legacy 12V instruments and processors that all modern cars now use. By the way even my old boat pulling '97 Volvo will not stay running if its 12V battery voltage is too low. I found that out the hard way:) I miss my old push, then run and jump in, pop the clutch and go VW that would start almost without battery at all.

[@gasdorficmuncher9943]

tesla sell a 12v battery? I want one

[@AnhTrieu90]

No, it's aftermarket. But I sure hope Tesla will make one some day.

[@wavey61]

The issue I see with this is that lithium-ion batteries like to be in the middle in terms of charge state. Leaving it overnight every night fully charged can't be good for it. There needs to be some sort of software or circuit that monitors the aftermarket 12v li-ion battery. Either on the battery itself or within the software of the Tesla.

[@randyland1000]

Thanks you.

[@oleksandrdemchyshyn2452]

Mine 12v battery is 7 years old and works fine!!!!

[@paulnelson696]

Very helpful!

[@retrowave9491]

Nice video you have great knowledge

[@FasterThanTheSpeedOfScience]

Dead battery this morning on my 2019 Leaf. Had to use the key to get in and pop the bonnet open. Battery read 5v. I'm now charging the 12v battery. For the past year or so my Rolec wall charger hasn't worked so I've been using the plug in granny charger since that time. However, while the 12v battery is charging I plugged in the wall charger and now it's working again. I think I just saved £100s on a new wall charger. I'll be putting a new 12v battery on later today.

[@Mladjasmilic]

When my Yugo used to parked for a week, I hate to jumpstart it by pushing it. Good point is that car is light.

[@TekAutomatica]

almost as good as the Fiat 127 it was based upon! kzbin.info/www/bejne/o3Oxiqlqp8p7qbs