If you haven't seen my previous 2 videos on t his topic: th-cam.com/video/QLVFxgKnV0U/w-d-xo.html th-cam.com/video/fJH1r1s8B6Y/w-d-xo.html Please do not buy aftermarket junk like the Ohmmu battery. You will spend about 6 times the cost of replacing the OEM $85 unit! Even if you have to replace the OEM every few years, that's still less money over the life you'll probably keep the car! (and that's assuming the aftermarket unit would last that long!) If you liked this video, check out my other content: th-cam.com/users/ingineerixvideos You can also support the channel here: www.paypal.com/donate?hosted_button_id=DT4S6DVGSBX3W If you have any ideas for content you'd live to see, please let me know!
The OEM battery is now $165 or $265 with installation. I just bought the battery today at Tesla Corte Madera, CA and completed the installation, not very hard or very fun. I'll get myself something nice with the $100 I saved! Thanks for the video, I was thinking about getting a Ohmmu battery and am happy with my choice to stick with a stock Tesla battery after your review.
I had to change the 12 volt battery in my model 3 in the long term parking garage at SFO last October. While abroad, the Tesla app sent me notifications that the 12 volt battery was failing - and the SOC of the main battery dropped quickly - from 75% down to 20% in about six days. Luckily a friend was able to meet me at SFO with a replacement 12 volt battery from Tesla - and we had it changed in the garage in about 10 minutes. .(Greetings from Oakley BTW)
A failing lead acid battery can suck a huge amount of power just to keep itself at 12V. At the end it will basically boil itself dry after which it ceases to be a battery anymore.
Interesting story! You could have probably waited and changed it at home though, but glad you got it solved! Yes, the car will have to keep the contactors closed to support the failed battery, so it's like leaving sentry mode on.
As a new Tesla owner, and being new to EVs, I really appreciate the way you explain everything. You got a new sub, and I look forward to checking out your other videos!
Thank You So much. My Tesla Model 3 flashed a warning that the 3 year old battery needed to be replaced. And I was going to buy this new battery to replace the lead battery in my car. Luckily I found your video before making this mistake.
I'm an electrician/ electronics guy and the owner of an older Model S. When my 12v battery died I saw these aftermarket batteries advertised and wondered how they could possibly interface with the existing vehicle design for a lead acid battery. I know there's a lot of people that are way smarter than me and perhaps they had somehow created a BMS that would interface, but I felt too dubious about it and replaced it with another lead acid battery. I'm so glad I did now. Thank you for sharing your wealth of knowledge.
Thanks Phil for this video. Very informative and interesting. I am glad I decided to stick with Tesla's PbA replacement batteries! They lasted about 5 years on both my Model S and Model 3. As you point out, it is easy and inexpensive to do these replacements.
Probably one of the most concise and valuable information videos I've seen about Tesla 12v batteries and the aftermarket Lithium replacements to AVOID AT ALL COSTS. Since they're priced so high, it's easy to do. Thank you very much for the education and warnings.
I really appreciate you making this video. I totally agree. My odometer is at around 60k miles, and I just did my first lead acid 12v battery replacement. I didn't get any warnings but did it because it was just so cheap and easy, and I didn't want to be stranded in the middle of freeways. $80 from the counter it was. So cheap and so easy. No need to spend that expensive $500 for the lithium battery for which my 2021 model 3 isn't designed. Now, I am a huge believer of aftermarket parts ONLY when I know what they really are. For EVs, I know NOTHING! That means stay to the bone stock and use only genuine parts!
I would add, however, that some number of the lead-acid batteries died in the 2 to 3 year range - like mine. Unfortunately I fell for the hype of the Ohmmu and it did result in error messages as you pointed out. They would not refund my money. I just had to buy a Tesla lead-acid battery anyway.
@@NoInfoFound same here, regarding the battery only lasting about two years. The next one held for like 8 months but that was replaced under warranty. Glad I never considered anything but an original replacement.
Great video - this explains some issues/behavior I've seen and corrects some misconceptions I had about the new battery! One note: there is a very specific edge case problem with the 'new' Tesla/CATL 12V battery C rev that will cause it to pop the e-fuse and in newer firmware reset after 20 seconds. The D rev supposedly fixes this issue by upping the current limits in hardware (and software.) We had this issue pop up during an autocross, due to lots of current in/out of the rack per the Tesla engineer who helped us look at the issue and gave us the above info. Just a FYI for those that might watch this and have the same issue!
Wow! I had the Ommhu on my list of things to upgrade on my May 2021 Model 3. I was of course waiting for the existing Lead Acid battery to die before replacing it. But not anymore. This opened my eyes to how bad (and how overpriced) the Ommhu product is. Such a shame. Do you think there is any way to get a well engineered aftermarket LFP battery that mimics the existing Lead Acid battery?
Very Informative, Thank you. I had thought about doing the Ohmmu battery swap. Not anymore. I had no idea the OEM lead acid was the cheap. $85 from Tesla is nothing compared to typical automotive batteries these days. What is the AH rating of the 12V lead battery. Is the OEM battery AGM or flooded cell?
I don't recommend LFP for the reasons I talked about in the video. If the BMS opens because the car thinks it's charging a lead-acid, you get alerts, and then stress out the PCS. For $85 every 5 years, it's not worth it either.
Thank you so much for this video. I am the owner of an Ohmuu 12v battery for my 2019 Model 3 and it lasted about 4 years. It did a fine job for those 4 years. But now the car won't start (12v is dead) so I am looking at my options. You really made the case for why these Ohmuu batteries are not a good idea. I will get a standard lead acid replacement. Cheap, simple and safer. You really have an impressive knowledge of batteries!
So glad I found this video. I was just about to get one of those Ohmmu batteries. Will stick with the led acid. Honestly it's not that big of a deal to have the old tech battery. When Tesla switches to 48v, that will be the game changer.
Good thing I saw this video. Before I'd for sure hook that battery up to the bench power supply and try to charge it - not anymore. Just connect jump leads to the car and activate battery in service mode!
Luckily the internal BMS prevents external charging, the explosion was caused by someone recharging it by cracking it open and bypassing the internal BMS. People don't understand dendritic damage.
Great video (as are all of yours). Just passed the 4yr mark on my 3 and was tempted to go non-OEM when the time comes; thanks to you, now I know better 👍
Wow,thank you for this informative video.. I was so close to buying an Ohmmu battery but this certainly has changed my mind! You saved me $400! New sub
Great presentation on the battery system. At 4 years on my 2020 Tesla Y ownership I am doing a preemptive battery replacement. It's worth the peace of mind knowing we should be safe while traveling for only $85.
I tried the Ohmmu battery three years ago. It came with the battery terminals reversed from the OEM battery, and I returned it. Your internal battery discussion makes me very glad I did return it.
Very interesting video, thank you. My model 3 12V battery failed after about 3 years and I replaced it under warranty. I was not tempted to get that lithium iron replacement due to the cost. Now I know it’s a total no-no anyway. I am surprised by the low cost of the Tesla lead acid battery, much lower than the equivalent from an auto parts store. I remember researching it at the time and a compatible non-Tesla one has to be group 51R, AGM.
Wow. Really good info as always. My Model Y is only about 18 months old so I'm not too worries anytime soon about 12v bat failure but I probably would have gotten the Ohmu battery thinking it'll last forever being a LFP. But it totally makes sense why the Ohmu battery throws a bunch of errors. Essentially the lead acid battery is acting like a capacitor on the 12v bus. Could be easily fixed if you could tell the PCS to limit it's voltage so the BMS on the Ohmu doesn't have to cut out due to cell over voltage.
Good advise on that Li-ion LVB as I know many people have tried that very thing. I hate that I even suggested thinking it was a true LFP cells and was safe to do.
I'm always impressed by the master knowledge that you display in your videos. Thank you very much for putting in all the work it takes to get to the bottom of all the details.
Wow, I have been looking to replace with ohmmu, thx for making this video. I will not replace it with anything other than lead acid at this point. Even every 3 years for $85 battery replacement is nothing.
An update for everyone. I purchased a battery from Tesla today. It was $182 not $120. The warranty on it is 12 months 12,000 miles. Tesla told me they make the batteries. It says made in Korea on it. Next time I will use a battery from the auto parts store….3 year or better warranty. This model x is junk. Extended warranty is worthless. I will probably cancel my order for the truck. Very disappointed in Tesla.
Had a software update last year that made the contactors close all the time. No warnings about battery though, but I disconnected the 12V and let it sit over night and it still read as 100% SoC on my 3 year old model 3. Put a load on it and no significant dip in voltage. Fingers crossed for a 6+ year battery.
If the contactors are closed all the time, then it's never using the 12v battery. Keep in mind this is NOT normal unless you have sentry mode on, and will result in a lot of miles of range lost each day you aren't driving the car.
The Tesla LV system is such an interesting topic, glad you keep posting on it! Why Tesla chose the lead acid was a favorite interview question for my old manager. Im really curious why they ended up going with the lithium LV battery. If the bom cost is really 2.5 times the lead acid I cant really see the benefit. Overall the system is definitely more complex and we had engineered out most of the warranty replacements of the lead acid even back in 2017. I feel like the time to do the switch would be when they go to 48V systems as the Lead acid versions at that range are not nearly as price competitive.
Thanks! My estimation on the BoM cost of this is well under $50. Tesla (Elon) promised to never attempt to profit on service, but clearly this is not the case. I would have went with a larger capacity LFP with a proper BMS if I was going to do it. Going with NMC and raising the bus voltage to 15.5-16v was a bad idea, it's creating all kinds of problems for the aftermarket too.
I replaced my Model 3 lead acid battery at 5 years (110,000 miles) even though it was still working fine. I connected a Bluetooth battery monitor to the battery to see how often my car was waking up to charge it. Was waking up every 4 hours. Decided to replace it with an enhanced flooded lead acid from AutoZone and it now wakes up every 8 hours. This will reduce cycles on my high voltage contactors, which are way more work and money to replace than the lead acid. I opened up my original lead acid and saw that the water level was low in it and I could see the plates clearly. This contributed to the reduced capacity.
On my Model 3, every year when I do my annual maintenance the negative terminal is always covered with green crusties. This is usually a sign of improper charging on a lead-acid battery. It always tests good though.
Lithium battery fires are no joke I had a 4s 10A pack do this exact thing in my basement it wasn’t cool, but luckily also didn’t burn my house down, I got the battery outside after it had puffed and hissed but seconds before it burst into a fireball
My YLR build June 1,2021. Did not get the 12 volt lithium and the bio weapon filter on my car build . This must be starting sometimes in July. Though I was able to retrofit the bio weapon , cost 450 installed mobile service . It was worth it to have clean filter HEPA air coming in to the cabin.
Thanks so much for this valuable information. I had an early model S and its led acid battery lasted ~ 8 years. Tesla mobile tech changed it for $200! However, I noticed that technician installed/updated a new battery firmware and always since then wondered why?
The original Model S 12 V batteries were no longer available in 2020 when I had mine replaced. The Tesla tech installed new firmware so that the DC-DC would use the correct parameters to charge the new 12 V battery.
Yes, @George is correct here. The newer C&D model has a slightly different charging profile, so to make it last longer, they have a setting in the Gateway for this specific model (C&D Nano). It's not firmware, just a setting the gateway uses to modify the charge algorithm.
It would be cool to know how Tesla is able to detect the 12v lead acid getting weak/needing replacement. Maybe the voltage drop upon the HV contactors closing in?
Lead-acid battery degradation can be easily seen by the voltage drop when the battery is under the load. So they just need a voltage and a current sensor for the 12V circuit.
They "coulomb count" all current into/out of the battery, that's why it's super-important not to hook anything else up to the battery. Once the car sees the total amp-hour capacity go below a set threshold, it will set the "replace battery" alert.
Nice video, as usual. How often do the HV contactors close to charge the Li low voltage battery when the car is sleeping. If it's a lot more often will that not put more wear on them?
They have gotten the sleep loads down enough that it's very infrequent. (as long as no aftermarket equipment) The contactors should last the life of the car in this case.
Just a heads up. There is a procedure for not just changing but resetting the warning on the 12v tesla systems. The omu will work. You can actuality put your car into service mode. Unlock the gateway and set it up for lithium. Also if you put a brand new lead acid in your tesla and it still says service 12v battery. You just need to turn the climate control off. Remove the neg 12v cable. Lift the back seat. On passenger side there's a grey lv contactor plug. Disconnect it. Wait 30 seconds. Reinstall neg cable. Connect contactor plug and you're set. Most of the time if your 12v battery goes low it will tell you to replace it even if it's charged back up and good. The procedure will clear the warning without replacing the battery. If it happens again then you will need to replace it.
Thanks for the video. Unfortunately, I've had to replace my 12v battery twice now. Once at 3 years and again 18 months later. Tesla reps gave me no info on how to prolong the life of these batteries. I wish I new how to make it last longer. It is frustrating.
Great topic, I've always been curious about how these work. Also really interesting on the other aftermarket lithium battery, haven't seen very much information on those besides where they're sold. Thanks for sharing
Thank you for the deep dive. Very insightful! To be fair to Ohmmu, they did recently redesign their BMS within the past few months, and it's supposed to get rid of a lot of the Tesla alerts on the screen. It also includes a Bluetooth module to give more details on its health. I haven't had a chance to test it out yet, but this is what they've told me.
It's good that they made improvements, but I'd still stay away from Ohmmu. It's hard to trust them after their disregard for safety with their initial battery design.
It's just not worth it. You are spending almost 6 times more money for a less-reliable solution! Not to mention a new $2000 PCS if the Ohmmu causes it to fail. $85 every 5 years is NOTHING. Just keep it OEM and enjoy your Tesla!
I was one of the suckers that bought an Ohmmu battery. It has never worked for the very reason you point out. They have made a few revisions along with promises for a fix to no avail. Im stuck with a $500 paperweight, as I put the original battery back in. They refuse to refund, stating its Teslas fault and not their own
I and a lot of other Tesla owners never received the 12v battery about to fail error. Instead received a bunch of error codes. The car would not charge. Car operations still worked and drivable. Wall charger was pumping out power but the car would not accept it. Look like PCS issue as not doing an AC to DC conversion. Also getting 0miles charging. Car was towed to Tesla. Turned out to be the 12v battery. The $130 battery install turned out to be $330 as Tesla tacked on 1 hr diag fee which incl testing out charging circuit/battery pack, testing out my charging cable, checking AC charging was ok, supercharging to 80%--car was down to 10%, clearing out codes. If I received the 12v failing error, would have simply had Tesla replace the battery. Wish Tesla did a better job with the 12v proactive warning.
great video... although it is disappointing to see tesla move a part that has a common interface in the industry to something proprietary. Hate to see people become less and less able to do maintenance on their cars with interchangeable parts. But this info is great!
I think their goal was to eliminate the 4-6 year replacement of the lead-acid battery and save costs, but looks like their dependence on a supplier (CATL) didn't go as anticipated.
Just because you haven't had to replace an expensive PCS, doesn't mean it's not going to happen. It's risky, there is plenty of evidence out there to support my assertion.
Thanks for all the great information. With other cars I've owned, I've had good luck rejuvenating a dying lead acid battery by adding distilled water to the cells. The batteries might be good for another few years after that simple bit of maintenance -- and it can often be done more than once. Tesla's lead acid batteries aren't user-serviceable to allow this. I managed to pry the top panel off mine (was quite the ordeal) and add water (it took a lot of water -- was fairly depleted) -- but only got another month or two of life out of it. My guess at the time was that I polluted the cells by using a silicone adhesive to re-attach the top panel (since it had been glued on originally and wasn't designed to just snap back on) -- but perhaps you could give better insight. The distilled water thing is usually so effective -- I wish Tesla's lead acid batteries allowed for it. $85 isn't a huge amount -- true -- but 25 cents worth of distilled water is far better, and there's no time spent driving to a service center.
I agree. The OEM lead acid are not AGM but maintenance-free flooded lead acid batteries. I opened up the top cover of mine after 5 years (110,000 miles) and saw the lead plates inside. The water level was really low. My battery still worked fine and I had no errors, but it had a reduced capacity and my car was waking up more often than usual to charge it.
Thanks for the great video! Question, is there any recommended / safe locations to connect aftermarket accessories to constant battery, ignition and ground. I’m struggling to find constant battery as you mentioned in your video due to the low amp hours of the 16v battery it shuts off all non critical loads. What loads stay on? where can I find them? and are they safe to connect a 100mA active 25mA sleep draw?
At a friends 2015 Model S the system popped up a warning to replace the 12V battery soon. On my 2014 Model S there was no warning but i noticed an increased overnight phantom drain paired with more frequent clack noise from the HV contactors when the car was parked. Then one night during a software udate the 12V battery died and the car was bricked, i could not open any doors. Luckily on older S you can access two posts behind the nose cone and i could hook up a power supply. The car was still undrivable (due to the incomplete software update) but i installed a battery from my ride-on mower and Tesla shot through another software update. It worked but the car complained about the wrong battery. To my surprise the new Tesla battery was only AU$160, which is a fair price. I live 500km away from the next SC and i was very happy that it was possible to fix a bricked car OTA. Any other manufacturer it would have been a super expensive tow truck job.
Good story! Yeah the update process depends on the 12v battery because they have to shut down the HV to update it's components. That's usually when you find out it's weak. (or the car does)
My 2014 p85d with 130k on it still has the original battery. I have gotten the batter replacement warning twice. Both times, I removed the clamps from the posts, cleaned the posts with stainless steel wool, and replaced the clamps. The key issue is the clamp design, it is stainless steel folded sheet metal and has the nut and bolt both made of the same grade of stainless. The nut and bolt will Gaul and bind if not treated with anti seize, and the stainless clamp on the lead post appears to loosen over time. I really don’t think the primary issue is the failure of the lead acid battery, instead it is increased resistance through the posts and inability to deliver or take sufficient current. Btw, I am an engineer with 35 years experience, not just some rando
I would replace this as a preventative measure. It's not worth "chancing" it. You will probably have a failed software update soon that leaves your car undriveable. The car depends on the reserve capacity while updating software in the HV battery.
Hi, nice video! So if I get it right, you could use an old 12 V lead-acid to jump start a newer model that has the Li-ion 12 V battery? Could you even run the car with it? (85 $ replacement vs 200$)
Great info here, I stumbled on this video while researching how the power outputs work in Teslas (wondering if they turn off automatically or if they can be set to stay on (lets say I want to run a 12v mini fridge).
Really I advise against this. Safest move is to use a portable power station. Tesla also voids your battery warranty if you do this. ("Stationary power" is specifically called out in the warranty)
Hard to understand why the new LV battery is not a LFP ? Wouldn’t a 4S LFP Pack better align with standard voltages required for existing devices if Tesla is not going to step down the sockets or supply 12v nominal voltage at the trailer for a brake controller?
Thank you for the informative video. I have a 2023 MY so I found that the small capacity 15V lithium battery is limiting my camping option. I ended up getting one of those portable battery "generator", so I have 2 questions for you sir: 1) What's the tell tale sign that the DC converter is charging the LV pack? (coming from AGM, I would see a 1.5V different) 2) How much current does the DC converter provide when on/charging the LV pack? (so I can estimate how much I can draw from the 12V without depleting the LV batt). Thanks in advance!
Just run a line from the Audio Amp power in the trunk and use that to drive a relay to the PCS connection on the Penthouse. (USE A FUSE!) You can drain 100A without any issues. The biggest issue is finding an inverter the allows up to 16.5V DC.
Cheers for another informative video, Ingineerix! I'd like to point out one thing though, and it is that you have a directional mic or some 3D mixer when you record. Your voice is all over the place and mostly to the right when you talk, is there a way you can force regular stereo audio when you record? From us headphone lovers, cheers.
Thanks for pointing this out. I do these videos on a budget using my phone camera, no external mic, but I'll check into this, or at least downmix to mono in the future if it's a problem.
If I’m running a high power aftermarket stereo, what is the best way to hook up the additional lithium and ultra capacitors? I have them hooked to the PCS’s main post under the seat now, but that is draining the system power to the point where the led acid battery under the hood gets drained too and the car shuts down.
Hi Phil, I just got a Tesla Model 3 with the 16V Li-Ion battery. It is a company car and was standing in the parking lot for 3 weeks and when I was trying to use it the first time it did nothing. Couldn’t open the car or anything. After watching a few TH-cam videos I found how to open the frunk when the 12V battery is dead and got to the Li battery. I am not an expert, but assumed that jump starting with another car would work to open the door and connected another car battery to the plus and Earth poles without touching the Li-Ion battery. It started the system and I finally got into the car and was able to open the charge port to plug it in. I kept the HV battery on charge and had the car jump connection running for about an hour as I assumed it might need the 12V power to run the computer system (I assumed the 12V battery was dead). Do you think connecting the jump leads to another battery for longer could have ruined the Li Ion battery? Basically after I disconnected the 12V battery supply it came with a lot of error messages. I couldn’t drive it off after charging the HV to 40miles as the car said the voltage is too low. I am a bit worried, but I am hoping the HV battery will charge the small battery over the weekend and then everything will be fine. I talked to Tesla on the phone and they said they could still see that the small battery had some juice in it. However, they also said I should be able to drive it. One of the error message (a479) is saying that I need to push down a connector until locked in place, but I never took anything out so I am not sure what it means. Sorry for the long message, but I wonder if you had any thoughts. Thanks
If you haven't seen my previous 2 videos on t his topic:
th-cam.com/video/QLVFxgKnV0U/w-d-xo.html
th-cam.com/video/fJH1r1s8B6Y/w-d-xo.html
Please do not buy aftermarket junk like the Ohmmu battery. You will spend about 6 times the cost of replacing the OEM $85 unit! Even if you have to replace the OEM every few years, that's still less money over the life you'll probably keep the car! (and that's assuming the aftermarket unit would last that long!)
If you liked this video, check out my other content: th-cam.com/users/ingineerixvideos
You can also support the channel here: www.paypal.com/donate?hosted_button_id=DT4S6DVGSBX3W
If you have any ideas for content you'd live to see, please let me know!
The OEM battery is now $165 or $265 with installation. I just bought the battery today at Tesla Corte Madera, CA and completed the installation, not very hard or very fun. I'll get myself something nice with the $100 I saved!
Thanks for the video, I was thinking about getting a Ohmmu battery and am happy with my choice to stick with a stock Tesla battery after your review.
I had to change the 12 volt battery in my model 3 in the long term parking garage at SFO last October. While abroad, the Tesla app sent me notifications that the 12 volt battery was failing - and the SOC of the main battery dropped quickly - from 75% down to 20% in about six days. Luckily a friend was able to meet me at SFO with a replacement 12 volt battery from Tesla - and we had it changed in the garage in about 10 minutes. .(Greetings from Oakley BTW)
A failing lead acid battery can suck a huge amount of power just to keep itself at 12V. At the end it will basically boil itself dry after which it ceases to be a battery anymore.
That process will also smell really bad.
Better at SFO than downtown SF. I bet catalytic converter thief's will soon target quick remove lipo packs. Less to carry and easier to hide.
Interesting story! You could have probably waited and changed it at home though, but glad you got it solved! Yes, the car will have to keep the contactors closed to support the failed battery, so it's like leaving sentry mode on.
(And Yes, I'm in Oakley!)
As a new Tesla owner, and being new to EVs, I really appreciate the way you explain everything. You got a new sub, and I look forward to checking out your other videos!
Yeah, I have quite a few you'll enjoy! th-cam.com/users/ingineerixvideos
Amazing video. Saved me from trying out those Ohmmu batteries.
Thank You So much. My Tesla Model 3 flashed a warning that the 3 year old battery needed to be replaced. And I was going to buy this new battery to replace the lead battery in my car. Luckily I found your video before making this mistake.
A must watch for all Tesla owners, especially those who went with this Ohmmu disaster bomb.
thanks. more interesting and informative than most Munro videos! Hard to believe considering this is a one man team.❤🔥💪
Thanks! Yeah, sadly I don't have the resources Munro does.
I'm an electrician/ electronics guy and the owner of an older Model S. When my 12v battery died I saw these aftermarket batteries advertised and wondered how they could possibly interface with the existing vehicle design for a lead acid battery. I know there's a lot of people that are way smarter than me and perhaps they had somehow created a BMS that would interface, but I felt too dubious about it and replaced it with another lead acid battery. I'm so glad I did now.
Thank you for sharing your wealth of knowledge.
Thanks Phil for this video. Very informative and interesting. I am glad I decided to stick with Tesla's PbA replacement batteries! They lasted about 5 years on both my Model S and Model 3. As you point out, it is easy and inexpensive to do these replacements.
You're welcome! I'll do a video showing how to replace it soon.
Thank you. I was looking at the Ohmmu and now I will stay with old tech :)
Probably one of the most concise and valuable information videos I've seen about Tesla 12v batteries and the aftermarket Lithium replacements to AVOID AT ALL COSTS. Since they're priced so high, it's easy to do. Thank you very much for the education and warnings.
Excellent content Phil, you just saved me from an expensive mistake. So glad you are back sharing your valuable expertise with us! Thank you!
I really appreciate you making this video. I totally agree. My odometer is at around 60k miles, and I just did my first lead acid 12v battery replacement. I didn't get any warnings but did it because it was just so cheap and easy, and I didn't want to be stranded in the middle of freeways. $80 from the counter it was. So cheap and so easy. No need to spend that expensive $500 for the lithium battery for which my 2021 model 3 isn't designed. Now, I am a huge believer of aftermarket parts ONLY when I know what they really are. For EVs, I know NOTHING! That means stay to the bone stock and use only genuine parts!
Wow, thanks for that deep dive on the original lead-acid in the Model 3 and the info on the new Li ion battery.
I would add, however, that some number of the lead-acid batteries died in the 2 to 3 year range - like mine.
Unfortunately I fell for the hype of the Ohmmu and it did result in error messages as you pointed out. They would not refund my money.
I just had to buy a Tesla lead-acid battery anyway.
@@NoInfoFound same here, regarding the battery only lasting about two years. The next one held for like 8 months but that was replaced under warranty. Glad I never considered anything but an original replacement.
Thanks, you're welcome! I have 2 other prior videos on this topic as well. Check the description.
Great video - this explains some issues/behavior I've seen and corrects some misconceptions I had about the new battery! One note: there is a very specific edge case problem with the 'new' Tesla/CATL 12V battery C rev that will cause it to pop the e-fuse and in newer firmware reset after 20 seconds. The D rev supposedly fixes this issue by upping the current limits in hardware (and software.) We had this issue pop up during an autocross, due to lots of current in/out of the rack per the Tesla engineer who helped us look at the issue and gave us the above info. Just a FYI for those that might watch this and have the same issue!
Interesting, Thanks for posting that! This is exactly why you need a stiff 12v bus. Autocross is severe duty.
Wow! I had the Ommhu on my list of things to upgrade on my May 2021 Model 3. I was of course waiting for the existing Lead Acid battery to die before replacing it. But not anymore. This opened my eyes to how bad (and how overpriced) the Ommhu product is. Such a shame. Do you think there is any way to get a well engineered aftermarket LFP battery that mimics the existing Lead Acid battery?
Sounds like your 2021 car might already have a better lithium 12 volt battery, since that is the year they switched.
Very Informative, Thank you. I had thought about doing the Ohmmu battery swap. Not anymore. I had no idea the OEM lead acid was the cheap. $85 from Tesla is nothing compared to typical automotive batteries these days. What is the AH rating of the 12V lead battery. Is the OEM battery AGM or flooded cell?
I don't recommend LFP for the reasons I talked about in the video. If the BMS opens because the car thinks it's charging a lead-acid, you get alerts, and then stress out the PCS. For $85 every 5 years, it's not worth it either.
Early cars had flooded, later were AGM in most cases (but it varied). It's 45Ah as I show in the video.
Thank you so much for this video. I am the owner of an Ohmuu 12v battery for my 2019 Model 3 and it lasted about 4 years. It did a fine job for those 4 years. But now the car won't start (12v is dead) so I am looking at my options. You really made the case for why these Ohmuu batteries are not a good idea. I will get a standard lead acid replacement. Cheap, simple and safer. You really have an impressive knowledge of batteries!
Thanks for this video. Sticking to an OEM battery when it goes bad.
Phil, I’m so glad to finally have this explained to me and I hope that lots of other Tesla owners find it as informative.
Your're welcome!
So glad I found this video. I was just about to get one of those Ohmmu batteries. Will stick with the led acid. Honestly it's not that big of a deal to have the old tech battery. When Tesla switches to 48v, that will be the game changer.
Agreed, I can't wait to have a look at the 48v system!
Good thing I saw this video. Before I'd for sure hook that battery up to the bench power supply and try to charge it - not anymore. Just connect jump leads to the car and activate battery in service mode!
Luckily the internal BMS prevents external charging, the explosion was caused by someone recharging it by cracking it open and bypassing the internal BMS. People don't understand dendritic damage.
Great video (as are all of yours). Just passed the 4yr mark on my 3 and was tempted to go non-OEM when the time comes; thanks to you, now I know better 👍
Wow,thank you for this informative video.. I was so close to buying an Ohmmu battery but this certainly has changed my mind! You saved me $400! New sub
You're welcome!
Great presentation on the battery system. At 4 years on my 2020 Tesla Y ownership I am doing a preemptive battery replacement. It's worth the peace of mind knowing we should be safe while traveling for only $85.
Thanks for the fantastic information! Always a pleasure to watch your videos.
Thanks, much appreciated!
I tried the Ohmmu battery three years ago. It came with the battery terminals reversed from the OEM battery, and I returned it. Your internal battery discussion makes me very glad I did return it.
Very interesting video, thank you. My model 3 12V battery failed after about 3 years and I replaced it under warranty. I was not tempted to get that lithium iron replacement due to the cost. Now I know it’s a total no-no anyway. I am surprised by the low cost of the Tesla lead acid battery, much lower than the equivalent from an auto parts store. I remember researching it at the time and a compatible non-Tesla one has to be group 51R, AGM.
You're welcome! Glad you kept the OEM!
Thank for you this video. I would have bought an OHMMU if I didn't see this. Coming up to 4 years of ownership and no issues.
Yeah, probably a good time to go ahead and replace it. (Before you have issues)
Wow. Really good info as always. My Model Y is only about 18 months old so I'm not too worries anytime soon about 12v bat failure but I probably would have gotten the Ohmu battery thinking it'll last forever being a LFP. But it totally makes sense why the Ohmu battery throws a bunch of errors. Essentially the lead acid battery is acting like a capacitor on the 12v bus. Could be easily fixed if you could tell the PCS to limit it's voltage so the BMS on the Ohmu doesn't have to cut out due to cell over voltage.
If your Model Y is only 18mth old then it would have the newer Li-Ion battery anyway. This change occurred in 2021 and was mentioned in the video.
Very well said. Thank you for educating me a little on the 12v battery.
Thanks!
Good advise on that Li-ion LVB as I know many people have tried that very thing.
I hate that I even suggested thinking it was a true LFP cells and was safe to do.
I'm always impressed by the master knowledge that you display in your videos. Thank you very much for putting in all the work it takes to get to the bottom of all the details.
Thanks!!!
Wow, I have been looking to replace with ohmmu, thx for making this video. I will not replace it with anything other than lead acid at this point. Even every 3 years for $85 battery replacement is nothing.
Very informative channel. Thank you very much
Didn't know! We just bought a 2023 Model 3 which has the new LI battery. Thanks for the great info and video!!!
How do you get tesla EPC to give you pricing?
You have to apply for an account, it's not easy!
Thanks for the video. I hope you can do more. I look forward to them.
I definitely intend on it! Please also check out my back catalog: th-cam.com/users/ingineerixvideos
Thank you for this information! I have purchased one used and very happy I didn’t try to use it. (21 model S)
Excellent video! Very informative. I talked to Tesla yesterday, 12v batteries are now $120.
An update for everyone. I purchased a battery from Tesla today. It was $182 not $120. The warranty on it is 12 months 12,000 miles. Tesla told me they make the batteries. It says made in Korea on it. Next time I will use a battery from the auto parts store….3 year or better warranty. This model x is junk. Extended warranty is worthless. I will probably cancel my order for the truck. Very disappointed in Tesla.
Glad to find a reinforcement to why I shouldn't buy the Ohmmu.
Had a software update last year that made the contactors close all the time. No warnings about battery though, but I disconnected the 12V and let it sit over night and it still read as 100% SoC on my 3 year old model 3. Put a load on it and no significant dip in voltage. Fingers crossed for a 6+ year battery.
If the contactors are closed all the time, then it's never using the 12v battery. Keep in mind this is NOT normal unless you have sentry mode on, and will result in a lot of miles of range lost each day you aren't driving the car.
I changed my battery to this OHMMU and had 0 issues. I have a 2021 Model Y as well.
Just because you have not YET had an issue, doesn't mean you wont. If you do have a PCS failure, it will cost thousands. Is it worth it?
Agreed on mystery packs not listing their string/parallel setups. Need nutrition facts stickers on the sides of these things!
Thanks for the info: It will save Tesla owners many dollars.
Nice to see you back again (:
Thanks to you just ordered my battery from Tesla. 👍🙏
Pretty damn good video!
Every Tesla owner should see this video.
Thanks for the tips. 👌
You're welcome!
Invaluable information of owning a Tesla.
The Tesla LV system is such an interesting topic, glad you keep posting on it! Why Tesla chose the lead acid was a favorite interview question for my old manager. Im really curious why they ended up going with the lithium LV battery. If the bom cost is really 2.5 times the lead acid I cant really see the benefit. Overall the system is definitely more complex and we had engineered out most of the warranty replacements of the lead acid even back in 2017. I feel like the time to do the switch would be when they go to 48V systems as the Lead acid versions at that range are not nearly as price competitive.
Thanks! My estimation on the BoM cost of this is well under $50. Tesla (Elon) promised to never attempt to profit on service, but clearly this is not the case. I would have went with a larger capacity LFP with a proper BMS if I was going to do it. Going with NMC and raising the bus voltage to 15.5-16v was a bad idea, it's creating all kinds of problems for the aftermarket too.
Thanks so much for this video!
Wow, awesome, much appreciated!!! Feel free to email me if you ever have questions.
I replaced my Model 3 lead acid battery at 5 years (110,000 miles) even though it was still working fine. I connected a Bluetooth battery monitor to the battery to see how often my car was waking up to charge it. Was waking up every 4 hours. Decided to replace it with an enhanced flooded lead acid from AutoZone and it now wakes up every 8 hours. This will reduce cycles on my high voltage contactors, which are way more work and money to replace than the lead acid. I opened up my original lead acid and saw that the water level was low in it and I could see the plates clearly. This contributed to the reduced capacity.
Yeah, replacing it every 4 years is a good idea. Keep in mind the car expects AGM chemistry, so you might run into issues with the aftermarket.
On my Model 3, every year when I do my annual maintenance the negative terminal is always covered with green crusties. This is usually a sign of improper charging on a lead-acid battery. It always tests good though.
Very useful info. Thanks!
Lithium battery fires are no joke I had a 4s 10A pack do this exact thing in my basement it wasn’t cool, but luckily also didn’t burn my house down, I got the battery outside after it had puffed and hissed but seconds before it burst into a fireball
Exactly, you have to treat them with respect.
My YLR build June 1,2021. Did not get the 12 volt lithium and the bio weapon filter on my car build . This must be starting sometimes in July.
Though I was able to retrofit the bio weapon , cost 450 installed mobile service . It was worth it to have clean filter HEPA air coming in to the cabin.
Thanks so much for this valuable information.
I had an early model S and its led acid battery lasted ~ 8 years. Tesla mobile tech changed it for $200! However, I noticed that technician installed/updated a new battery firmware and always since then wondered why?
The original Model S 12 V batteries were no longer available in 2020 when I had mine replaced. The Tesla tech installed new firmware so that the DC-DC would use the correct parameters to charge the new 12 V battery.
Yes, @George is correct here. The newer C&D model has a slightly different charging profile, so to make it last longer, they have a setting in the Gateway for this specific model (C&D Nano). It's not firmware, just a setting the gateway uses to modify the charge algorithm.
It would be cool to know how Tesla is able to detect the 12v lead acid getting weak/needing replacement. Maybe the voltage drop upon the HV contactors closing in?
Lead-acid battery degradation can be easily seen by the voltage drop when the battery is under the load. So they just need a voltage and a current sensor for the 12V circuit.
A $10 battery tester can tell you. ALL modern computerized cars should be able to inform you on the state of the battery.
They "coulomb count" all current into/out of the battery, that's why it's super-important not to hook anything else up to the battery. Once the car sees the total amp-hour capacity go below a set threshold, it will set the "replace battery" alert.
Nice video, as usual. How often do the HV contactors close to charge the Li low voltage battery when the car is sleeping. If it's a lot more often will that not put more wear on them?
They have gotten the sleep loads down enough that it's very infrequent. (as long as no aftermarket equipment) The contactors should last the life of the car in this case.
Just a heads up. There is a procedure for not just changing but resetting the warning on the 12v tesla systems. The omu will work. You can actuality put your car into service mode. Unlock the gateway and set it up for lithium. Also if you put a brand new lead acid in your tesla and it still says service 12v battery. You just need to turn the climate control off. Remove the neg 12v cable. Lift the back seat. On passenger side there's a grey lv contactor plug. Disconnect it. Wait 30 seconds. Reinstall neg cable. Connect contactor plug and you're set. Most of the time if your 12v battery goes low it will tell you to replace it even if it's charged back up and good. The procedure will clear the warning without replacing the battery. If it happens again then you will need to replace it.
Thanks for the video. Unfortunately, I've had to replace my 12v battery twice now. Once at 3 years and again 18 months later. Tesla reps gave me no info on how to prolong the life of these batteries. I wish I new how to make it last longer. It is frustrating.
Great topic, I've always been curious about how these work. Also really interesting on the other aftermarket lithium battery, haven't seen very much information on those besides where they're sold. Thanks for sharing
Thanks for the Super Great public safety announcement 👏👏👏
You're welcome. Once I saw the explosion video, I knew I had to make a video. (among the other reasons)
Wow, Thanks!
I almost bought one of these. 😮
Thank you for the deep dive. Very insightful! To be fair to Ohmmu, they did recently redesign their BMS within the past few months, and it's supposed to get rid of a lot of the Tesla alerts on the screen. It also includes a Bluetooth module to give more details on its health. I haven't had a chance to test it out yet, but this is what they've told me.
It's good that they made improvements, but I'd still stay away from Ohmmu. It's hard to trust them after their disregard for safety with their initial battery design.
It's just not worth it. You are spending almost 6 times more money for a less-reliable solution! Not to mention a new $2000 PCS if the Ohmmu causes it to fail. $85 every 5 years is NOTHING. Just keep it OEM and enjoy your Tesla!
Not just that, but they clearly "took the money and ran" for most all of their customers so far.
@@Ingineerix I appreciate your insight. Thanks!
Great informative video. Really appreciate this content
Thanks!
I was one of the suckers that bought an Ohmmu battery. It has never worked for the very reason you point out. They have made a few revisions along with promises for a fix to no avail. Im stuck with a $500 paperweight, as I put the original battery back in. They refuse to refund, stating its Teslas fault and not their own
Exactly! For the price they are charging for that crap, you'd think they'd be better servicing their customers.
I and a lot of other Tesla owners never received the 12v battery about to fail error. Instead received a bunch of error codes. The car would not charge. Car operations still worked and drivable. Wall charger was pumping out power but the car would not accept it. Look like PCS issue as not doing an AC to DC conversion. Also getting 0miles charging. Car was towed to Tesla. Turned out to be the 12v battery. The $130 battery install turned out to be $330 as Tesla tacked on 1 hr diag fee which incl testing out charging circuit/battery pack, testing out my charging cable, checking AC charging was ok, supercharging to 80%--car was down to 10%, clearing out codes. If I received the 12v failing error, would have simply had Tesla replace the battery. Wish Tesla did a better job with the 12v proactive warning.
Thanks. Very informative
Just wondering: are you involved with the Maxwell EV van conversions? Great content BTW.
Yes, That's my "day" job. I am CTO, and developed all the tech we use in the vans.
Really Thanks for this video… saved me BIG TIME !
great video... although it is disappointing to see tesla move a part that has a common interface in the industry to something proprietary. Hate to see people become less and less able to do maintenance on their cars with interchangeable parts. But this info is great!
I think their goal was to eliminate the 4-6 year replacement of the lead-acid battery and save costs, but looks like their dependence on a supplier (CATL) didn't go as anticipated.
Thorough and objective. Thank you!
You're welcome!
never had an issue with my ohmmu battery in the 2 years i had it in the car. lots of other people also had good results with it.
Just because you haven't had to replace an expensive PCS, doesn't mean it's not going to happen. It's risky, there is plenty of evidence out there to support my assertion.
Thanks for all the great information. With other cars I've owned, I've had good luck rejuvenating a dying lead acid battery by adding distilled water to the cells. The batteries might be good for another few years after that simple bit of maintenance -- and it can often be done more than once. Tesla's lead acid batteries aren't user-serviceable to allow this. I managed to pry the top panel off mine (was quite the ordeal) and add water (it took a lot of water -- was fairly depleted) -- but only got another month or two of life out of it. My guess at the time was that I polluted the cells by using a silicone adhesive to re-attach the top panel (since it had been glued on originally and wasn't designed to just snap back on) -- but perhaps you could give better insight. The distilled water thing is usually so effective -- I wish Tesla's lead acid batteries allowed for it. $85 isn't a huge amount -- true -- but 25 cents worth of distilled water is far better, and there's no time spent driving to a service center.
I'd recommend against this. Your time is worth more than the $85. I've seen someone do this, and it leaked acid all over the frunk.
Old Model 3 use not AGM, but usual lead-acid battery. You can find this info in Hankook data sheet
I agree. The OEM lead acid are not AGM but maintenance-free flooded lead acid batteries. I opened up the top cover of mine after 5 years (110,000 miles) and saw the lead plates inside. The water level was really low. My battery still worked fine and I had no errors, but it had a reduced capacity and my car was waking up more often than usual to charge it.
Yeah, I think you are correct.
Thanks for the great video! Question, is there any recommended / safe locations to connect aftermarket accessories to constant battery, ignition and ground. I’m struggling to find constant battery as you mentioned in your video due to the low amp hours of the 16v battery it shuts off all non critical loads. What loads stay on? where can I find them? and are they safe to connect a 100mA active 25mA sleep draw?
Thank you for this informative video; cutting corners is pricy and leads to double work.
4-6 years? Mine lasted 26 months. I do appreciate your information. Thanks.
That's a pretty rare short life. Where do you live? Even so, it's only $85 so not a big deal. Think of what you would have spent on an ICE car by now!
Good stuff as always
Thanks Arnold!
Thanks man! You’re a Legend!
Excellent info. Thanks for sharing.
At a friends 2015 Model S the system popped up a warning to replace the 12V battery soon. On my 2014 Model S there was no warning but i noticed an increased overnight phantom drain paired with more frequent clack noise from the HV contactors when the car was parked.
Then one night during a software udate the 12V battery died and the car was bricked, i could not open any doors.
Luckily on older S you can access two posts behind the nose cone and i could hook up a power supply. The car was still undrivable (due to the incomplete software update) but i installed a battery from my ride-on mower and Tesla shot through another software update. It worked but the car complained about the wrong battery. To my surprise the new Tesla battery was only AU$160, which is a fair price.
I live 500km away from the next SC and i was very happy that it was possible to fix a bricked car OTA. Any other manufacturer it would have been a super expensive tow truck job.
Good story! Yeah the update process depends on the 12v battery because they have to shut down the HV to update it's components. That's usually when you find out it's weak. (or the car does)
My 2014 p85d with 130k on it still has the original battery. I have gotten the batter replacement warning twice. Both times, I removed the clamps from the posts, cleaned the posts with stainless steel wool, and replaced the clamps. The key issue is the clamp design, it is stainless steel folded sheet metal and has the nut and bolt both made of the same grade of stainless. The nut and bolt will Gaul and bind if not treated with anti seize, and the stainless clamp on the lead post appears to loosen over time. I really don’t think the primary issue is the failure of the lead acid battery, instead it is increased resistance through the posts and inability to deliver or take sufficient current. Btw, I am an engineer with 35 years experience, not just some rando
I would replace this as a preventative measure. It's not worth "chancing" it. You will probably have a failed software update soon that leaves your car undriveable. The car depends on the reserve capacity while updating software in the HV battery.
Hi, nice video! So if I get it right, you could use an old 12 V lead-acid to jump start a newer model that has the Li-ion 12 V battery? Could you even run the car with it? (85 $ replacement vs 200$)
Yes, you can jump it, but you can't "use" it because the car will not charge it properly.
Great. Thank you for the video
Danke! from Germany for this great information 🤗👍💡💡💡
Awesome, Thanks!
fascinating...
If you want to look at the MPP earthX lithium ion battery, let me know. I have an extra.
I'd love to! You can find my email in the "about" tab of my channel (use a full browser, not a phone): www.youtube.com/@Ingineerix/about
Great info here, I stumbled on this video while researching how the power outputs work in Teslas (wondering if they turn off automatically or if they can be set to stay on (lets say I want to run a 12v mini fridge).
Really I advise against this. Safest move is to use a portable power station. Tesla also voids your battery warranty if you do this. ("Stationary power" is specifically called out in the warranty)
Hard to understand why the new LV battery is not a LFP ? Wouldn’t a 4S LFP Pack better align with standard voltages required for existing devices if Tesla is not going to step down the sockets or supply 12v nominal voltage at the trailer for a brake controller?
Agreed, I think they wanted the low cell resistance of this particular battery so they could keep it under 100Wh.
Thank you for this video
Thanks!
Thanks James, Much appreciated!
Thank you for the video.
Thank you for the informative video. I have a 2023 MY so I found that the small capacity 15V lithium battery is limiting my camping option. I ended up getting one of those portable battery "generator", so I have 2 questions for you sir: 1) What's the tell tale sign that the DC converter is charging the LV pack? (coming from AGM, I would see a 1.5V different) 2) How much current does the DC converter provide when on/charging the LV pack? (so I can estimate how much I can draw from the 12V without depleting the LV batt). Thanks in advance!
Just run a line from the Audio Amp power in the trunk and use that to drive a relay to the PCS connection on the Penthouse. (USE A FUSE!) You can drain 100A without any issues. The biggest issue is finding an inverter the allows up to 16.5V DC.
Great info, as always!!
My twelve volt Atlas AGM battery over the counter at Tesla service center was $176.14 out the door!! January 2024 $85.00, I WISH!
Cheers for another informative video, Ingineerix! I'd like to point out one thing though, and it is that you have a directional mic or some 3D mixer when you record. Your voice is all over the place and mostly to the right when you talk, is there a way you can force regular stereo audio when you record? From us headphone lovers, cheers.
Thanks for pointing this out. I do these videos on a budget using my phone camera, no external mic, but I'll check into this, or at least downmix to mono in the future if it's a problem.
If I’m running a high power aftermarket stereo, what is the best way to hook up the additional lithium and ultra capacitors? I have them hooked to the PCS’s main post under the seat now, but that is draining the system power to the point where the led acid battery under the hood gets drained too and the car shuts down.
Hi Phil, I just got a Tesla Model 3 with the 16V Li-Ion battery.
It is a company car and was standing in the parking lot for 3 weeks and when I was trying to use it the first time it did nothing. Couldn’t open the car or anything.
After watching a few TH-cam videos I found how to open the frunk when the 12V battery is dead and got to the Li battery.
I am not an expert, but assumed that jump starting with another car would work to open the door and connected another car battery to the plus and Earth poles without touching the Li-Ion battery. It started the system and I finally got into the car and was able to open the charge port to plug it in.
I kept the HV battery on charge and had the car jump connection running for about an hour as I assumed it might need the 12V power to run the computer system (I assumed the 12V battery was dead).
Do you think connecting the jump leads to another battery for longer could have ruined the Li Ion battery?
Basically after I disconnected the 12V battery supply it came with a lot of error messages.
I couldn’t drive it off after charging the HV to 40miles as the car said the voltage is too low. I am a bit worried, but I am hoping the HV battery will charge the small battery over the weekend and then everything will be fine. I talked to Tesla on the phone and they said they could still see that the small battery had some juice in it. However, they also said I should be able to drive it.
One of the error message (a479) is saying that I need to push down a connector until locked in place, but I never took anything out so I am not sure what it means.
Sorry for the long message, but I wonder if you had any thoughts. Thanks