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model y long-range 12v battery
- Thread starter sam2020
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Siddhartha
Member
Quick question about the 12v battery. I looked, but couldn't find info. I had mine replaced yesterday (M3) and the rated range increased. When the old 12v died (the day before) I was getting errors that said "replace soon," and "non-essential features may be disabled," but most notably was the "power drain at idle may be increased."
Now, I had been a bit concerned about my rated range showing a good deal of main battery degradation, but now that the 12v is replaced, perhaps the range increased again as it is no longer draining the main battery as much?
What do you guys think? Is this the case, or simply a "reset" that occurred with the replacement of a failing 12v?
Now, I had been a bit concerned about my rated range showing a good deal of main battery degradation, but now that the 12v is replaced, perhaps the range increased again as it is no longer draining the main battery as much?
What do you guys think? Is this the case, or simply a "reset" that occurred with the replacement of a failing 12v?
If the 12V battery was failing, not holding a charge then this could affect estimated range as the high voltage battery is being tapped more frequently, for longer period of time to top up the 12V battery. If you normally have Sentry mode active this would drain the 12V battery faster, require even more charging from the high voltage battery.
Or - the complete power down reset the measurement and the car will be relearning as you drive again.
This thread is interesting. Here is a question: Since it appears an AGM would not be a good choice as a replacement battery for the AtlasBX and until Ohmmu gets their charging issues resolved (should be soon) would a EFB battery work well since it is designed for start/stop operations and it is essentially a modified flooded battery? The most recent software updates now do an overcharge test to try ad find AtlasBX failures sooner. So the question is how much of an overcharge would take place and would an EFB handle it OK?
I don't have any experience with owning a vehicle that uses an enhanced flooded (lead-acid) battery. The EFB are used in modern ICE vehicles that use Start/Stop technology.
My 2016 Chevrolet Volt used a GM Delco AGM 12V battery, however the Volt would use one of the two electric motors and power from the 14kWh lithium battery pack to start the Volt's ICE as needed. Cranking the Volt's gas engine was sort of like spinning a toy when using a 100 HP motor. Volt owners reported some early failures with the AGM battery but many of the Volt 12V batteries lasted beyond 4 years, some even 8 or 9 years. I replaced the 12V AGM battery in my Volt after 3 years. I have a conductance tester that indicated the Volt's 12V battery should be replaced and I don't like to be surprised by a dead 12V battery.
For those who own a Tesla vehicle that uses the AtlasBX flooded lead-acid 12V battery this is probably the best, perhaps only choice for Tesla vehicles (other than the Ohmmu lithium battery that costs three or fours times as much.)
I tested the 12V AtlaxBX battery in my 2020 Model Y at 12 months and it tested ok. I will test the 12V again this June when the battery will be age ~24 months. If my 12V battery conductance tester indicates that the 12V in my Model Y should be replaced, I will have it replaced at that time.
It might be just pseudo science but in my experience the conductance tester is an accurate means of determining the health of a 12V battery. When a 12V battery is new then conductance within the battery is at maximum and resistance within the battery is at minimum. * Over time (years) the conductance falls as the resistance rises. This is due to sulfation of the plates within a 12V lead-acid battery. At the 4 to 5 year point the conductance and resistance curves cross. From that point in time on the internal resistance continues to climb until about year 9 when most would agree the battery (if it was still functioning at all) is done.
* The conductance and resistance curves are the inverse of each other, except for variations due to temperature.
The Tesla Model Y now comes with a lithium 12V replacement battery module. The nominal voltage of the lithium battery is 15.5V. The 12V accessory system in the Model Y now provides up to 16V to charge the lithium battery module. This can cause issues with 12V to 120V power inverters, some other 12V accessories that will see the higher voltage and automatically shut down due to the higher input voltage.
FWIW, my MYP was was at the SC having its 5th spoiler installed under warranty, and I purchased a 12V battery to have on hand in my garage just in case. Cost was $85 plus tax, very reasonable.
Swapping it is fairly easy if you have some basic tools and follow the directions.
If I get the 12V message, can be back in full condition in about 20 minutes without an appointment at the SC. For $85, I’ll take the insurance.
Swapping it is fairly easy if you have some basic tools and follow the directions.
If I get the 12V message, can be back in full condition in about 20 minutes without an appointment at the SC. For $85, I’ll take the insurance.
Did you connect a 12V battery maintainer to the spare 12V battery while it sits unused?
mstatkus
Member
Battery is fairly easy to get to. Bracket on the top holds it down. Its all 10mm socket from memory.
I actually keep a set of tools with me and you don’t really need much since most the bolts are all the same.
- small hand ratchet
- small extension
- 10mm socket ( covers about every bolt under the frunk )
- T27 Torx ( covers most interior screws )
- wheel cap puller
- Body clip remover
I also had switched to the Ohmmu Lithium as I really didn’t want to deal with a Battery failure 2-3 years down the line as most the time I’m on the highway its a road trip. Tesla started monitoring voltage and this trips the “Low voltage warning” in the car. Basically makes it so your car can’t take a software update or in some cases will halt charging until you reset. This became highly irritating, so I put my old lead acid back in until this gets sorted. Since its Tesla’s monitoring its mainly waiting for a solution to keep the monitoring happy, or Tesla to give us a option to disable the monitoring.
Please keep in mind most the time it trips the warning at the tail end of a road trip. But it did happen once while charging the car in the garage. I put a negative cutoff switch in so I didn’t have to keep removing the HEPA filter in my car as the reset process required cutting the high voltage feed, disconnecting the negative lead, and then reconnecting. I just got sick of it; so back to the 29lb lead acid battery.
Lead Acid batteries are generally much more expensive than I remember now. Many of the ICE cars I had were starting to cost $150. Being in WA most mine last as long as 9 years vs my time in AZ where they at best worked 4. I came at it more interested in just weight reduction, and longevity, but that battery monitoring just wiped out my ability to use it. So if it never gets resolved I have a 12V solar project battery I guess lol.
Last edited:
mbdionio
Member
You will need to disconnect the high voltage relay connector located under the passenger side, second row seat. You will need to leave the the door propped open or you won't be able to get back into the vehicle after changing the 12V battery and reconnect the high voltage relay connector. (See Youtube video for changing Tesla Model 3/Y 12V battery)
OK, so I did actually install an Ohmmu (Lithium) 12V battery in my 2020 MY about a year ago (original battery still OK, just wanted to check it out). The Ohmmu battery worked fine for about a week, but then I started receiving messages from the car that the 12V battery needed to be replaced. So I re-installed the original lead acid 12V battery and returned the Ohmmu battery for refund. More recently, I inquired of my service center if the Tesla lithium battery (now used in more recent vehicles than mine) could be used as a replacement for the lead acid battery. The response was "no", the reason being that there is a new charging process (also hardware?) in the cars with the OEM lithium battery installed and it cannot be duplicated in older vehicles like my 2020 MY. This agrees with my experience in testing out the Ohmmu lithium battery and Ohmmu did also solicit my support for their attempts to convince Tesla to specifically make (software?) changes to allow proper monitoring and charging of the Ohmmu lithium battery.
My question: do you have independent knowledge as to whether or not the new Tesla lithium 12V battery is compatible with older (lead acid AGM) 12V batteries from, for example, 2020 model Y vehicles? As far as I can tell, the answer is still "no". Thanks...
I have a 2020 M3 and a 2022 MY. The MY lithium is a totally different connector and no to the standard SAE posts. They are not interchangeable and the electrical system has been boosted to 15.5 volts. I do have the latest Ohmmu V4+ with the latest firmware in the battery from a early December build. 3 weeks no issues. Battery rests at 99% 13.4 volts. On wake charges to 14.8v. Rests there for a bit then the car takes some amps from the battery and drops voltage to 13.4v. At that point it stays there until the next wake up cycle. The latest firmware on the V4+ 15 volt BMS trip limit for over voltage and I think this is where the previous versions were having an issue. Tesla has been adjusting charging mapping with time and this is the latest Tesla software behaviors. Ohmmu looks like the finally figured out how to adapt and also Tesla software behavior doesn't trip the BMS. Some of the early V4+ batteries were beta test batteries and in early December Ohmmu adjust the firmware of the battery. The V4+ now can be monitored via the Ohmmu app. Future app revisions you will be able to flash the battery with updated software if needed. I had the Tesla lead acid (still in my garage) but in the interim used the DiehardEV battery designed for M3/Y and both worked fine but I had more confidence in the DiehardEV as it was an AGM while the Tesla battery is a straight lead acid. IF the Ohmmu ever fails (and so far is has bee working perfectly) I would switch back to the DiehardEV. Too many stories of the Tesla Lead battery swelling or leaking despite the member that swear by it. I live in a cold climate and want no battery issues in the winter. I also want a battery I can put in and forget about for years. Hence the Ohmmu. Also, with the Ohmmu car sleeps normally just like it had a lead battery.
I have not seen any information that the new 15V lithium battery module is compatible with older Model 3, Model Y vehicles. I have not yet had to replace the original 12V lead-acid battery in my 2020 LRMY. I started out checking the 12V lead-acide battery every year, now every six months. The battery just tested good in December '22 at about 2.5 years.
I use a Topdon battery tester that has proven to be accurate in determining when a 12V battery needs to be replaced. This tester can perform a conductance test among other battery test and starting routines. (The resistance and conductance curves of a 12V lead-acid battery are practically identical, although one is inverted, other than for temperature effects. (The resistance curve starts out low and the conductance curve starts out high.) At about the 4 year point the curves cross paths; from then on the internal resistance in the battery exceeds the conductance; a 12V lead-acid battery is done, finito by ~9 years (if the 12V battery lasts that long in use.) I imagine that within the next year to 18 months my Topdon battery tester will indicate that the 12V lead-acid battery should be replaced. Then I will contact Tesla service and request that they replace the 12V battery. If Tesla service pushes back I will probably go head and have the 12V battery changed at my expense, that is if I still own the 2020 LRMY at that time.
If u were asking about charge ur battery, charge at 14.4, dont have to charge 16. 12v Battery fully is 13. If u let it rest 30 minor 1 hour. It calm to 12-13v. I have new 12v deep cycle tested. AGM tested, seal maintenance free tested. Charger: lead acid charger 6/12v bought at home Depot 39$ auto off when fully charged. Thanks for all of you guys post, I learned stuff. By the way, used to have 2018 M3 less than 2 year, trade in for 21 M.Y... now as I am pay more attention more I know about 12v battery have problem.
I thinking about build lithium battery 3.7v x 4= 14.8 or 16.8 when fully charged, charge cycle 2000, this would last 10 years or longer, and it should solve the lead acid battery issue, but then I have to wait for waranty over or at least 4 years.
See?,,, I kinda get this anxiety about range, now 12v could die while on freeway or middle of nowhere in the desert like the 5 youngster in 20ist years old in the desert during my trip to north California. The model X dead on highway around 1 AM... total darkness, I wait with them in my M,Y till two truck come about 1 hour.
What do u guys think? Beside confirm with Testla before swap in.
Have any one try this yet?
Any one know Tesla website or email address to ask that they do reply? The service in my area not reply my service question in app. Tesla.com never reply message. Thanks a lot.
Hi, Can u post with picture your test? can you please post the link of that Topdon tool you bought/have? I would like to see n buy. I am testing a lot battery, but using multi meter. How about also make YouTube video n give link to see, I love to see it. Thanks
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