Can a 12V LiFePO4 Battery Replace the Lead Acid Battery in a Car? 

I directly replaced my car battery with a 46AH Lifepo4 battery in June 2018 out of curiosity. It only lasted for 3 years (until July 2021) when I expected it to last for 10 years! It was still able to start my car until the end but what I noticed was the engine stalls while we were on neutral in the middle of traffic. When I replaced my battery with SLA, my car went back to normal.

I would really like to see you open and look at the Antigravity lithium car battery. They're very expensive and seem to get a lot of positive feedback. They have some pretty great claims too.

While it's correct that most LFP batteries on the market today aren't suitable for starting engines, there are plenty of LFP battery options that are perfectly capable of doing so which still have under temp charging protection and good CCA outputs. I have several vehicles with LFP starting batteries: 1.) A Farmall Super H tractor using an EarthX battery (Which are actually designed and approved to crank aircraft engines where they see very cold temperatures). This battery has been in service since 2018 with no issues and has started the tractor in zero degree weather. 2.) I have a diesel motorhome with a 6.6L diesel engine. I replaced the two lead acid batteries with two Banshee Lithium Starting batteries. These have been in service since 2019 with no issues, and have started the engine in zero degree weather many times. 3.) I have a diesel Jeep Liberty where I replaced the lead acid starting battery with a Banshee Lithium battery. In service since early 2020. 4.) My parents have a diesel motorhome where they replaced the two lead acid starting batteries with two Dakota Lithium engine starting batteries (Just installed this year so no real use on them yet) 5.) The 8kW diesel generator in my motorhome is cranked by two BattleBorn batteries, in service since 2017 and has started the generator in below zero degree weather many times over the years without any issue. 6.) I also have several smaller engine equipment like garden tillers, portable generators. All have been switched to LFP starting batteries because they last longer. None of the above applications required making any modifications whatsoever aside from swapping the batteries. The notion that LFP can't crank an engine is ludicrous. Any decent LFP battery, especially one designed for engine cranking, will have a BMS that protects against charging in cold weather and no that won't cause a "voltage spike" if the BMS shuts off charging. I don't understand where notion came from. Don't just repeat things you've "heard". If you think there's a voltage spike, prove it. Show us where the spike occurs. These FETs usually have large resistors across them so when they shut off they can still dissipate any "spikes" that might occur from the alternator. And you can absolutely disconnect the battery from a running car and nothing of any significance happens. I have done it many times when testing batteries and alternators. As long as the battery has a properly designed BMS then an LFP battery will crank a car motor just fine. My diesel powered vehicles need a lot more cranking amps than the average gas car, so if these batteries can crank a diesel motorhome in zero degree weather then I think they'll start your Corolla just fine. I have been using LFP batteries to start engines for several years now and I have not had any issues.

You should test antigravity car batteries lifepo4 chemistry. BMW and other car manufacturers have been using lifepo4 with success for years. Many autocross racers and track cars use antigravity batteries since there more reliable and weight is less than lead. Hope you buy one to tear it down to see how they make them for car use.

Thank you for taking the time to explain this so clearly. I have always wondered why I cannot use a LiFePo4 battery for my car or boat as a starter battery. The manufacturers always recommend to use it only for a trolling motor of a boat. Thanks again, I was still planning to try using a LiFePo4 battery as my starter battery. Now I understand what can happen, so I definately won't do it.

Very good explanation of the differences in LiFePO4 and Lead Acid. I build my own LiFePO4 batteries and do not use a BMS. I use them to power all sorts of things, even to start the outboard motor on my boat. I have specific chargers for LiFePO4, I use QNBBM balancers to keep cells in balance during charging and discharge. I monitor voltage of the batteries during use and storage. I have been following battery technology for five decades. Do not just go putting this that or the other thing batteries into use unless you understand all the factors necessary. Any battery with sufficient energy to start a large engine can also quickly start a large fire.

I've been using a LifeP04 8AH battery to start my 54" Zero turn 27HP Lawnmower. I also use a LifePO4 8AH battery to start my 15HP Hydraulic Power Pack. So far I've had no problems. This summer I'll be testing the same 8AH LifePO4 Battery on my Harley. Of course all my uses are only during the warm seasons

Just want to share my experience. To cut story short. Recently caught a hit and run case while parking, therefore decided to build a 125A lifepo4 battery with a BMS can handle 200A discharge to replace my Lead starter battery, so I can run my 3 car cams 24/7 for week without worries. I am using for two months now, so far very satisfied with the battery performance. Tips and my finding. 1. I add a super capacitor (360F x 6 nos, 16.2V60F) in parallel to the battery with 60A fuse. Reason is to help to jump start the engine (although I know my 200A lifepo4 battery is strong enough to handle the 2.0 Camry starter that will draw around 180A+-), second to buffer the voltage from alternator, also sudden cut-off from BMS ( Do it based on instinct). 2. I also add a TVS diode at the alternator to protect the alternator from the back emf if the battery turn-off by the BMS while running. (Based on research, and hope my research is correct) 3. I set the single cell over voltage at 3.65v and low voltage protection at 3v to prevent frequent on-off of BMS. Nevertheless I set my pack over voltage at 13.9v and turn-on charging voltage at 13v. Reason been the alternator voltage is always fluctuating, so when BMS sense 13.9 volt, the BMS turn-off the charging, the lifepo4 battery will has a voltage reading around 13.3v or 13.4v volt which is around 80% to 90% SOC. When the battery fall below 13v (around 40% SOC) the BMS will turn-on and start charging again. The main reason I doing so is because I want the battery to always fall between 90% or 80% to 40% SOC so I can enjoy max charging cycles of 4000 or more. 4. I stay in Singapore, base on my observation, my Lifepo4 +ve terminal, Battery and BMS temperature is around 50+- degree celsius, the battery will get hotter to around 56 or 57 degree celsius when parking. Therefore I have a build in Thermostat switch (activate at 55 degree celsius) to activate a 12v mini fan to cold the battery down. So far I only experience it turn-on one time while I am parking.

I have an electric car which has a lead acid battery to run the low voltage electrical system and it also powers the high voltage relay to engage the high voltage lithium drive battery. The 12v lead acid battery is a weak point in the system in my opinion. I would like to know if the lead acid battery can be replaced by a lifepo4 battery in my circumstance.

I just built a Lifepo4 12.8v battery pack and use it without a BMS and put an active capacitive balancer to keep the cells balanced. It's installed on my 2005 Ford Ranger with the WL diesel engine. It works just fine and has done so for a couple months. I'm in South East Asia.

I've used very small LIFEPo4 batteries as the sole automotive battery. Above freezing it's simple. I've put a lot of thought into doing it below freezing, but it adds a lot of complexity. Smart management,insulated battery box with electric heater...and possibly running warm coolant into that box as well....

I have not tried this, but if you connect a lifepo4 battery in parallel, there is small risk of losing 12v supply and your lead acid battery will last forever because it will basically be in float stage and never discharge even when the starter is used. It would be cool because you could turn the car off and still have a large battery system without the added weight of heavy AGM deep cycle batteries in the trunk!

Excellent overview of using a LiFePO4 as a starting battery - fets, under bonnet heat, low temperature performance and charging - kudos to your thorough and accurate knowledge and simple, well delivered explanations. Your honesty in outlining the limits of your knowledge is commendable too. There is a reason why I rush to see your videos, this probably has a lot to do with it.

I have a super cap under hood and small LifePo4 under back seat. When truck is off, they are in parallel. When truck is on and above 13v they are separated and charged independently. Also have temp sensor on the lifepo4 that switches between charging/heating. Going almost 3 yrs now. Expensive but I'll never have to buy a battery again. -- Love the supercap. Sat in parking lot after work one day watching someone try to jump off a truck that had left his lights on. After 15min of just hearing them getting nothing but clicks, clicks. I drove over, said hold my beer. Hooked cables to my truck, it started instantly. They both just stared in shock at how awesome Toyota trucks must be to be able to do that. I didn't tell them about my secret 10,000 amps. lol -- Must careful with what you "jump"/"power" though, A non resistive or non amps limited load will let the smoke out before you had intended.

About the only car worth using lithium 12v batts in , are ev, and hybrid cars, that do not start with 12v, if you have a stereo that needs more power,

Holy market opportunity. It's utterly *trivial* to design a lifepo4 battery for automotive use. For below-zero (and >14.6V) charging, shunt excess current into a warming circuit. Use a contactor instead of mosfets for disconnect. Monitor the terminal voltage for reengagement. Outstanding and accurate video as always. :) I'm just amazed how *bad* lifepo4 battery manufacturers are at producing reliable products, generally speaking.

Well, I have been doing it for many years. I will never use small cells with lower amp rating. I have 90AH plastic CALB Lithium iron phosphate cells in 4S configuration with 100 amp Daly BMS and 5A capacitive active balancer. Initially I had no BMS and I was overcharging some cells. Relocate your battery to trunk if you are concerned about high or low temps. These cells have no problem discharging at low temps just charging is disabled at low temp by Daly BMS. But as temperature rises the BMS will let it charge. Cranking amp at 3C of 90 amp or 270 Amp is not a issue. Honestly lead acid batteries are vulnerable to temps too. I was tired of sulfation and short storage life. As far as Alternator goes, you only need to worry about it failing if it is trying to charge a dead battery. But if you have a solar or plugin trickle charger than that is not a issue. Daly does allow you to set high amp disconnect. So set it low if you have a small alternator. I did upgrade mine to 200a alternator. Voltage is fine. My alternator goes to 14.3v and if cells are balanced than it has no issue. I did have to parallel two 100amp Daly bms to support higher cranking amps. They do have no problem with 150 amp surges. There is also a QUCC bms with contactor that can handle higher amps, But it will completely disconnect both charge and discharge circuits. Lead acid is old technology and lithium is the future. Now if you have not seen a out of box solution it does not mean it cannot be done.

New electric cars tend to ship with LiFePO4 12V batteries these days.

No, Maybe, and Yes. I've been researching this lately (this video is 2 years old). If you have gas engine powered car that uses a 12V lead acid battery to start the car, the LiFePO4 is not an option. It just does not work properly with an alternator (as this video implies). If you have a hybrid or an EV that only uses it's 12V to run accessories, then there are now a few conversion kits that allow a LiFePO4 to be used in place of their GEL cell 12V battery. That is car model specific though. The problem with adding the battery without the conversion kit is that the LiFePO4 battery will never fully charge up using it's 14.4 volt max charging voltage. In other words the battery will only charge up to about 30% before the car's battery charging circuit shuts off thinking the battery is fully charged. Of course all that is needed for this to work is a battery with a BMS that feeds back the proper information to the cars charging circuit. But that has not been invented yet. Never say never, someone will figure this out and kill the lead acid battery industry someday. It's just a matter of time and pollution wise, we will all be a lot better off.

Installing a LiFePO4 in conjunction with your existing lead-acid battery will eliminate any current surge... and regulate the voltage and will keep both batteries charged and warm in cold weather. This is the method that nobody mentions. No need to buy another battery for life! From my personal experience.

Simple, take some headway 38120hp cells designed for high current drain, put enough of them together to get the CCAs you need (under 2 litres 4 cells 325CCA, over 2 litres 8 cells 650CCA, bigger diesels 16 cells 1300CCA, etc), add a tiny inexpensive active capacitor balance board, unbridge the solder enable jumper and attach a tiny low current relay to that and trigger it from your start/run circuit so it's on when the engine is running and boom, reliable LiFePO4 setup in a car. 100AH is insane in a car unless you want to store it for 12 months without isolating it. I have 20 cars, 10 in use, 9 on LiFePO4 and of those 2 on 4 cells the rest on 8 and one boat on 16 cells (8.3 cummins). IE, I have 8AH on 2 cars, and 16AH on 8 cars and 32AH on the boat - why is this okay? Your battery ONLY has to run the starter motor, your alternator runs everything else. You need fresh belts for this as the charging is aggressive thanks to the low internal resistance. Correct that those precanned batteries don't work for it due to the electronics. And correct that you must be sure not to over voltage or under voltage your pack if you don't have a BMS, but reality is alternators are reliable and stable in voltage output and if you isolate or use frequently or match the capacity to the drain/time requirements you have, it's fine. I've been doing this for over 2 years now.

Gravity batteries makes automotive Lifepo4 batteries.

Explanation can be shorter and slower :) LiFePo4 cannot handle big Amps & cannot work in a hot env. Obviously under bonnet you can have more than 60 degree. One more thing people mention is charging current: while LiFePo4 can absorb big current, it can overheat alternator! So ATM LiFePo4 is no way for cars. Use capacitors! :)

in my case I didn't solve anything, I just placed the LFP battery in the trunk and wired it in parallel to the lead-acid, along with a reset switch for the BMS in case it tripped, nothing yet, the voltage drop leading to it is big enough to avoid overvoltage while charging, so essentially the car is working same as usual but now it can power accessories for a whole day and the lead battery could be dead and I wouldn't notice if I were to get rid of the lead acid, I would just build my own LFP with raw cells + active balancer, LFP wont just blow up with overcharging like Li-ion would, it'll just degrade faster, so maybe it lasts 10 years instead of 20, and freezing cold isnt a thing here, I've got a bunch of computer UPSs on raw LFP that so far have outlasted brand new lead acid units twice over even though one of them keeps the cells at 3.8v

Good video! I've been eyeing the Antigravity batteries for a while now. It looks like the company built their own BMS, and took into account a lot of the issues you describe (cold, thermal overrun, engine heat etc). They're expensive though, I would love to see a teardown on one of these!

Good video! For everyone asking this question, it's important to understand that there are different types of LiFePo batteries. There are different types of cells and different BMS'. In general, LFP batteries can be used in your car. I think it was Porsche who even started fitting LFP batteries to some of their production cars many years ago. But most of the batteries reviewed here cannot be used for all the mentioned reasons. You need the right cells, there are LFP cells with a charging temperature of down to -20°C and end of charge voltages of 4V, and the right BMS or just no BMS at all. A BMS is usually there to protect the battery from situations which are considered normal workload in a car, so most BMS' will just interfere with the normal operation and might stop you from using your car. So, if you desperately want to do it, get the right parts needed for the job. But, don't forget that your car battery is subject to excessive wear in normal operation and will be consumed over time. Switching from LA to LFP will not change this.

Here's an idea how it could work: When below freezing, a battery should have a heater and keep its temperature above freezing. When it gets near depleted (say 50% SOC), it should turn itself off and wait for demand. When it's needed again (when you want to start the car), it should refuse to work (provide no current) but start heating itself, such that if you waited a few minutes your car could start, once the battery is warm. You could use an app to configure things. Special safety measures could be taken to prevent disconnection when the car is running, probably add a supercapacitor just for safety measure and maybe a redundant BMS. Cars have many safety features already, electronics can be quite reliable.

Could I use it in a wheelchair.

Interesting to note that Tesla are now fitting in their model S plad a lithium starter battery. Of course it’s a lot different to an ice car as there’s no alternator or starter motor to worry about.

Hi thanks for the information. From what you’ve said the bus and temperature are the main issues. With that let me ask your opinion on LTO Cells which have a much broader range of low and high temperature charge / discharge capability. With no BMS and a balancer do you think that they would be a more viable alternative to lifepo?

LTO chemistry is the better choice for a starting battery to replace lead acid. It can operate well below freezing, has excellent high C rate discharge ability, pretty decent high temp, and with 6 in series, 14.8 volt charging will keep it well under it's max cell voltage, but also well above it's minimum. They aren't as energy dense as lifepo4 cells are, but still much better than lead. Toshiba makes cells specifically for this sort of purpose, many larger generators use them now. They handle being run flat much better too.

I've had a LiFePO4 battery in my lawn tractor for 2 years. Just saying.

My ride on mower battery has failed. I have a starter battery which is said to be rated for six cylinder use. Can I use this occasionally with my mower without harming it?

I remember a video where the lead battery was replaced by a bank of supercapacitors, with the support of a small lipo battery for voltage recharge. If it weren't for the price of supercapacitors, you could create such batteries for cars. There was "1 year update" and it was working just fine

i hear a "can't" man here. just try with lithium ion or lithium polymer pack. glove box in a a glass fiber plastic housing. add peltier for good measure in cold climate. if a jump starter lipo battery can be used idk why it couldn't take over a lead acid. the key is your shutoff switch and it's also fused. like everything, but double check, sometimes oems like to not do stuff

It's easy. You just need to brush a little Dodo bird oil onto your battery terminals before installation. It helps stop all the freezing problems and evens out the voltage. Amazon's all out right now, so just be a little patient.

I have a lithium iron battery attached by a dc to dc battery charger. Through this I charge a lithium iron battery which I then use for rv. Battery is far from heat source. Battery is not used for starting purposes.

I have a lifepo4 battery in my motorcycle, and it's been a great improvement over lead acid. It feels a little weak when cold, but running the headlight for 30 seconds first seems to warm it up and get it going hard and starts great.

Thank you I often wondered about this taught me a few things and probably saved me from a mistake

What if you run parallel, small lead acid with lithium? In theory that should work.

Very very useful information 👏👏👏 thank you brother for your very technical information 👍 Best regards from Philippines 🇵🇭

You're 100% correct about not disconnecting a battery while the engine running. The battery just in its inherent design absorbs those spikes that you know we see on the electrical system.

Due to their very low internal resistance they can overheat your alternator too.

I presume it would be OK to replace the 12V battery (that runs the LED Headlights etc.) in an EV assuming the the temperature is OK??

Sounds like the acid battery is better than the Lifepo4 batteries for vehicles without damage to the vehicles computers and wiring!...

Your not using any imagination or minor fixes to your listed issues.

QUESTION: so when do you start to see damage from low temp charging a Lifepo4 battery? I have purposely kept a 100ah lifepo4 in the freezer for 48 hours, then instantly charged it up at 15 amps. I then did a capacity test and it didn't lose any capacity. This battery obviously doesn't have low charging protection.... But does it need it? I still pulled over 100ah. I'm just curious how many times it needs to be charged below freezing before you see damage. It has to be more than 3 since I have done that process (freeze, charge, test capacity) and it still pulls 100ah....weird right?

This is a great overview, but how do Lithium chemistry batteries work on Electric vehicles? EVs don't have a heavy start up load, so they don't need cold cranking amps. The battery draw is pretty consistent I think, except when all the accessories are in full play.

I don't see any added value in LiFePO4 for starting a car, but well-known European supplier GWL sells them. They are Winston/Thundersky batteries without a BMS and can be used for starting small private planes. Big advantage there is the limited weight compared to SLA.

I purchased an XS power agm battery for my Toyota as its main battery. It cranks the engine just fine, but if i drive somewhere and park it, come back, it cranks slow. Drive it home, let the car sit for 5 days, its practically dead. There is no parasitic draw on the battery. Even though its not LifePO battery, maybe its not a suitable replacement for a cars main battery. These batteries were made for car stereo competition batteries.

Thank you for this excellent video. You have covered a lot of general information, and I found it very useful. I appreciate the explanation of the BMS and what it is designed to do, and on how some of the manufacturers bypass the BMS. I have been considering building my own portable vehicle jump start box using a LiFePO4 battery. I am primarily trying to get away from the weight of the lead acid battery. It has been difficult to come up with a LiFePO4 battery, that also has enough power to start a small block V-8, without breaking the bank. All I have discovered many of the things that you have explained in your video. I wish that I saw your video first. It appears there is a new classification of LiFePO4 batteries that they call “dual-purpose”. These batteries have the CCA rating, and are marketed for automotive use. WEIZE makes a 12V 60AH Dual Purpose LiFePO4 Lithium Battery, 800CCA, they call a Starting Battery Plus Deep Cycle Performance, Built-in Smart BMS, for Automotive use. The battery cost $250 so I will have to consider this purchase. Thanks again for the great information.

Lemmee tell yoo sumetin.. YOO don't want any BMS in this type of battery! If it disconnects it, the Voltage on alernator will skyrocket to 30+V and will damage everything in the electronic system that's currently "on".. like ECU, dashboard... You can do this battery DIY, they even sell cells that you can charge on -20°C with 20C charge/discharge 😲 and for about 120$ or € with Balancing circuit - don't take it for the money

So, what is the best setup to use the alternator to charge the lithium solar bank, but, to prevent back drain from the 12v LED Acid car battery drawing from the solar bank when engine is off?

LiteBlox, Antigravity etc .. companies is based on this demand. They make car batteries LiFePO4.

A NOCO GB150 Lithium Jump box started my 7.3 PowerStroke Diesel when both the vans's batteries were dead. And I can recharge the GB150 using the 12v power plug on my dash. It seems like a small step to make this all work without the lead acid battery. Maybe keep one small lead acid battery for when the van is running and the Lithium just starts the engine?

OMG I might have done this... what if its an EV a Nissan Leaf 2017 I have the BMS/12V ETC made from LIPo cells Might have blown the DC to DC regulator or the BMS in the Battery pack... I also have a 16DCV 1600Mf Boost pack.. It was a system I was putting on my EV bike...

LFP battery performance under low temperatures (

I have GS Brand batteries here in thailand, avergae air temp 35C, and they are totally useless, you go past their shop and its stacked up with dead ones. The heat inside the car engine bay is about 60C (I measured it ) The batteries I keep topped up with distilled water BUT they still sulphate and fail, pulse chargers do very little, I just had one, 1 year old (on my Nissan Channel) with evidence of boiling SO I saw your channel and decided NOT to switch to DIY lithium. Thanks indeed I agree with your findings - However 1 question -- as a backup plan is it a good idea to keep a high current 12 volt pack in the trunk of the car with jumpers as a backup to the Gs looneybatteries failing when away somewhere out in the boon docks, just to get the engine turned over? (deisel or petrol) Thanks for the very neat video.

I've been a mechanic for over 20 years. Not one single time have I damaged any component by disconnecting the battery while the car was running. I regularly use this method as checking an alternator. Not saying it never never happens. But it's never happened to me, therefore I continue on with my methods.

I have Lithum battery in my motorcycle for 20 years still working! If Lithium Battery could work in Cars it be Great. Engineering can make it possible but the $ manufactuers would loose would be astronomical!

Ohmmu (4yr warranty), Antigravity. I think the BMS fixes it and makes the magic happen. Prob even better for EVs, not much heat under hood. Save 40+ lb

Well, sounds like a no. Why is it then, when I parallel connect my solar battery bank to my vehicle starter batter, that there is no problem? I use my solar battery bank to spruce up the starter power because for some reason, my vehicle starter batter seems to degrade in power over time either because it needs to be replaced, or is just week. None the less, I can connect my solar batter bank to my starter batter for startup and charging purposes which - works. Why is this? Given your video, I understand how the BMS is configured incompatibly with vehicle starter voltage and amp configurations. However, I seem to enjoy a nice start up sequence when connecting my 500 amp our battery bank to my starter battery (using a battery switch) as needed, and it works well.. Is the combined connection making the BMS conflicts irrelevant? Thanks.

Interesting , I was thinking of replacing my electric cars battery for one of these as it only takes about 10a to start but hadn't thought of cold weather where battery will switch off , that won't be good . I was thinking doing this as my lead acid battery can just go flat due to the car not charging and discharging high current like it would in an ice car what's your thoughts?

I did it anyway and it works just fine... by the way, I'm a DIYer...

Lithium is ideal as a backup battery > to charge a starter CAPACITOR in case the one main battery dies. Im totally baffled why car companies still havent addressed the battery dying issue, even with 2024 cars i can run the stereo and kill the battery - HAHAHA, its like a conspiracy!

warmly welcome you guys using the Aolithium battery. Let me know if you want to be a dealer

I rarely drive my car. Winter is cold here. Keep lifepo4 warm for charging is a huge hassle.Lifepo4 BMS failing during driving is a risk. My plan is simple: car starting and running: connect lead acid(2 remote switches + 1 manual blade switch as backup). Disconnect lifepo4 through live 12V socket. Car off: Disconnect lead acid. Connect lifepo4.

Just swapped in 4kwh of lifepo4 batteries, 4x 280ah eve cells. it was basically drop in. basically because of how unique the electrical system is in my 2013 chevy volt, I am confident it is a niche case where you can simply drop in an appropriately built DIY battery. expecting about 15 miles of additional range by eliminating the 12v parasitic loads. here is why every point you brought up does not apply 1. Chevy volt starts its gas generator with the high voltage battery and does not have a 12v starter motor 2. DIY battery i built does not have a BMS. instead it has a small active balancer which is basically dumb analogue and shouldnt fail. even if it does, it will take awhile for the cells to go out of balance 3. the battery is mounted in the trunk, its under the floor so its not exposed to heat from the engine 4. where i live it goes below freezing for a month or two each year so i installed a 15w silicone heating pad and wrapped it with copper tape around the battery and connected it to a 1$ thermometer relay in line with a PTC fuse just in case a relay sticks. this will keep the battery above freezing 5. the chevy volt doesnt have an alternator, instead it has a DC-Dc converter from high voltage battery to 12v system, so its not going to burn out anything. some challenges you didnt address but i solved 1. the chevy volt expects a lead acid range of voltages and can undercharge the battery and cause it to go dead/very low state of charge after a month or two of driving. I added 200w of flexible solar to my roof and wired it into an mppt charge controller (epever, 30a) and that should take care of all the charging for the 12v system since its set to the appropriate lifepo4 voltages. 2. im optimistic that with the solar panels adding about 1.5kwh per day and the battery offsetting the ~600w/hr parasitic load from the 12v systems, the high voltage battery will last longer and give me more EV only range. this was a helpful video to get my head wrapped around the challenges that need to be overcome. there is a mob of people online on yt and on forums that are all saying its impossible to do. from my estimation if i am successful I will be the first person who has found a meaningful way to extend my EV's range with a 12v system alone. time will tell. ill keep my old AGM battery and a jump start pack in my trunk for the next month or two just in case ;) the 4kwh battery cost 350$ to build (which is not much more than a replacement agm now days) the solar panels cost 70$, the mppt was 30$. this is all pre biden tarrifs that were announced last month. the ROI since im offsetting $4.50/gal gas in WA state is around 3 months for the solar panels (already done) and 5 cycles of the lithium batteries. planning on making a video which explains how i did everything since there is literally no other source online of other people that are successful in this regard.

LiFePO4 is could be a marvellous car engine starter battery! Due to its very low internal resistance which leads to two factors: a very high cranking current (1,000 A easily) and very fast charge with quite high current (like 20 minutes at 200 amps). The two things LiFePO4-s don't like are: low and high temperature. At high temp they neither charge nor discharge (of course they do, but at cost of damaging themselves), at low temp they discharge very well, however charging them causes internal damage with very fast loss of the energy storage capacity. So you kinda need a traditional battery in parallel. You also need it as a buffer, because low internal resistance of a LiFePO4 battery makes it a quite bad buffer, your ECU is at risk of receiving high voltage/high amps peaks even thru the battery. By the way how well LiFePO4 gives high current at freezing temperatures makes it yet again a very cool car starter battery! So, in order to have it as a car engine starter battery you have to have a traditional battery in parallel, a chilled case for your LiFePO4 for hot weather, a heated case for cold weather, a low temp charge kill switch and a high temp discharge+charge kill switch. The chilled and heated case must cool down and warm up automatically (the temp sensors must be inside the battery, presumably between the cells).

Maybe re-visit this with anti-gravity, XS power. Go-lithium etc... alot of "vehicle rated" LiFePO4 batteries available now (most are pricey).

Another question...How to Lithium batteries connect to the charging system? Will the charging circuit set up for a lead acid battery be compatible with a Lithium one? I.E. can you just swap it out, and it will charge off the (alternator in an ICE car, Inverter in a n EV) without a problem?

Put a Super Super Kapacitor and Battery Relocation mine is in the Trunk Problems Solved.

If IC vehicle manufacturers would get off their collective asses and redesign cars for these batteries a **huge** amount of toxic recycling could be alleviated as lead/acid gets phased out. LFP4 battery recycling is a great deal less toxic. They just need to redesign vehicles to handle these batteries - via capacitors, environmental protection (warming/cooling), batteries in the trunk which many already do this technology could be adapted readily. Such adoption would also bring these batteries down from their current $500-600 cost to be more in line with good quality lead/acid ($250ish). Unfortunately, lead/acid batteries are a huge market with firmly entrenched companies that do not want any risk to their profits as a properly configured and maintained LFP4 could last 10 years versus 3 for lead/acid (those can last up to 5 years - optimally, but rarely).

I got lost in your vast knowledge of batteries in the first minute and I got your point not to use it in conventional car, but how about EV car as 12 V battery???

Recently saw a video from CARPRIME channel where these Japanese enthusiasts used that small Shorai battery to replace their old Panasonic battery in an older car. The benefits seem great, because they were going for lower resistance when it came down to the alternator circuit in the system, resulting in better electrical performance that would have been obvious in the driving of the vehicle. I have to do more research on which exact battery model they utilized, but the results seem promising.

Can we replace car battery with a bigger battery? like 12V - 150A or 200A . Perhaps is better with another extra battery? Looking for a converted camper Prius .

Can a 12V LiFePO4 Battery Replace the Lead Acid Battery in a Car? No, not really (at least yet) There - 3 seconds - why use 10 minutes to answer that simple question?!?

I put a massively underpowered lifepo4 in my Fiat 500e EV, worked for a few weeks, then on the freeway, it's different with no alternator

Battle Born has a Drop in Replacement ...... LTO Batteries kan work in -40

Fantastic youtube - most intelligent discussion on this topic!! Thank you sir.

Jeez I'll just go to Crappy tire and get another one, I have 2 of them sitting around.. my problem Is Im out of Money!!

Has anyone seen the new Cub-Cadet riding mowers that are electric. Saw some yesterday at Home Depot . Didn’t have time to check it out because I had a water leak under my sink. $4500 for what looks like a 42” cutting area. It on my wish list.

Kind of sounds like excuses for the bms. If you don’t use bms? What’s the problem? The problem is you were taught that won’t work. If you use it without a bms it’s 12 volt battery and as long as the cable is thick enough the problem is still we were taught not too. I say fuck that in the end it’s the same set up as lead acid battery acid has six cells 2 V each a lithium one would have three cells 3.7 V each. Tell me why not without making excuses for the BMS.

What about using 12V Lithium Iron battery for home use with UPS?

You need a BMS designed for a 12 volt system, quality wiring done by someone that understands just twisting wires together with a little electrical tape does not a safe connection make. also underhood temperatures aren't that extreme, your lead acid battery would fail catastrophically if those temperatures were as high as you suggest, however if you're still concerned battery relocation kits are an option so long as they have properly gauged wire / ie don't buy the cheapest Chinese slave labor produced one you find on Amazon. And finally if engine start discharge rates are of concern, automotive stereo capacitors are an option as they're used in vehicles with absurd systems that have amplifiers and gigantic subwoofers that dim your headlights when the base hits (a friend had a car like that in high-school with 4 15 in subs, 2 amplifiers etc... that in addition to making the car /a jeep grand Cherokee / sound like it was full beer cans, would almost kill the electrical system every time he listened to music, and yeah it was as awful a vehicle as it sounds) so he got hold of a large capacitor and then one more to alleviate the issue. I don't remember the rating they carried but certain race cars use them to prevent voltage drop during startup which would trigger a fault in their engines computer. So there you go, I've been running a lifepo4 battery in my vehicle since 2020 when I mysteriously found myself with some extra time on my hands and decided to convert from lead acid. They work just fine and are far safer than their lead+sulphuric acid counterparts

Wonderful topic I've been wondering the same thing, Thank you! I've personally used the battery tender one on my motorcycle and I had no issues with it for the 2 years I had it. I just bought a lithium starter battery for my lawnmower so I'll see how that goes.

I'm trying to explain to people around me that LiFePo4 are not suitable for automotive (appart from special ones like Golf cart that are not in severe environment)..... but it seems that people are dumb they just want .. to believe but they do not analyze facts ...

Seen your speech on google, verbatim... it's crazy... Sell those batteries playa.

Comprehensive vid. I had to put a marine ssb 650cca power sports lanplus battery into my 4wd diesel when my agm completely randomly collapsed while i was in a remote area i left battery in for two weeks before swapping it out. The lithium phosphate battery seems to be fine it did dump charge once while in my car i haven't used it on the boat since would it be damaged at all? I recharged it the lipo4 with a slow repair charge lithium charger and seems to be fine although i'm hesitant to put it into my boat again.

All true even EV's with 60 -70 kwh still use a lead acid battery for the 12 volt system. Some things are just easier that way. I did like the one you tested that used the alternator to heat the battery which shows some advanced thinking

I was thinking of taking one of those battery pack, car jumpers and keeping it in the vehicle with cables running out to the engine for engine, start ups, and re-charging the battery inside the vehicle off the cigarette lighter outlet. Would that work?

There is no reason why these can not be supieror to lead acid in everyway. They just need a bms designed for auto. For some reason there is only one company that i can find that does this and of course they charge a totaly unecessary 5X lead.

Thank you 🙏 Excellent explanation! Great work!

You're probably the smartest lithium guy on RU-vid and we have a serious problem... Will and watts247 started a raging fire yesterday involving the 5000es inverters that millions of people have bought, we need you to explain the situation to us and some kind of solution to make these somewhat safer for us. Please.

Super cap AND/OR a small traditional SLA or AGM.

Excellent Video!!!

I am looking for a lifepo4 battery for my generator (12V 20AH).

I’ve seen capacitors linked with a little LFP

What if you put an inverter on the car battery and use the ac output to charge the LiFeO4 in a trailer or camper?

What do you think about prius's. 12v batteries of them are for peripherals and for the relays of hybrid battery. They do not have a regular alternator, one of the motors starts the engine and it is connected to hybrid battery. The 12v battery is in the trunk, so heat is not an issue.