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Made In China Model Y has 15.5 Lithium battery to replace 12V lead-acid

e645824

Member
May 15, 2021
163
217
USA
According to reports yesterday, the Made In China Model Y has the 6.9 Ah 15.5 Volt lithium battery to replace the 12V lead-acid battery:


and are the same specs as the new Model S battery.

Previous rumors from July indicated that retrofits to existing Model Y owners would also be possible. But I haven't seen anything recently about this:


For backgrond, this page describes the new Model S battery:



I haven't been able to find any info on the connector itself. Is it just plus/minus or are there also signal/control pins as part of that new connector on the new low voltage battery. If the former, the retrofit for existing Model Y owners would be trivial.

For example, here are early photos of the new Model S battery. The two large cables are positive and negative. But what is that little green wire? If it is just case ground, then the retrofit for existing Model Y owners would still be trivial.

FFM3jovVQAE9Qmg

cite: https://twitter.com/JayinShanghai/status/1464575400684621826

Scott

--

MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021
 
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Schulz1983

Model Y LR AWD: Matte PPF, Vossen HF-1
May 14, 2021
623
434
High Ridge MO
According to reports yesterday, the Made In China Model Y has the 6.9 Ah 15.5 Volt lithium battery to replace the 12V lead-acid battery:


and are the same specs as the new Model S battery.

Previous rumors from July indicated that retrofits to existing Model Y owners would also be possible. But I haven't seen anything recently about this:


For backgrond, this page describes the new Model S battery:



I haven't been able to find any info on the connector itself. Is it just plus/minus or are there also signal/control pins as part of that new connector on the new low voltage battery. If the former, the retrofit for existing Model Y owners would be trivial. For example, here are early photos of the new Model S battery. The two large cables are positive and negative. But what is that little green wire? If it is just case ground, then the retrofit would still be trivial.

FFM3jovVQAE9Qmg

cite: https://twitter.com/JayinShanghai/status/1464575400684621826

Scott

--

MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021
Is it just me, or does it look like there is a bolt missing on that battery? Top left
 
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e645824

Member
May 15, 2021
163
217
USA
According to this video, starting at 12:16, you can see the cable that attaches to the new Model S 15.5 Volt lithium battery:


The green wire is there also, but I can't see the other end. It might be a case ground (for ESD reasons?) or perhaps a sensor in the connector to determine if the connector is actually connected to the battery.

For the new Model S battery, the Tesla Part Number from the parts catalog is 1598486-88-C. The connector is shown as Jonhon 345-3649

If the Made In China Model Y has the same battery and wiring harness as the new Model S, then it seems that the retrofit process would be straight forward as long as the existing unit that charges the low-voltage battery can reach a high enough voltage for the higher charge voltage that this lithium battery requires. If not, then that unit would have to be replaced also.

Scott

--

MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021
 

jcanoe

Active Member
Oct 2, 2020
4,374
4,546
Maryland
If the Li-ion 12V battery is rated at 6.9Ah and 15V (as stated in the article in the link) the lithium 12V is going to need to be charged (topped up) more often than the current 12V maintenance free (MF) flooded lead-acid battery (45Ah). The current lead-acid 12V battery can last about a full day powering the Tesla vehicle's essential systems (BT, LTE, alarm system) while the Tesla vehicle is in sleep mode. A 12V lithium battery with a 6.9Ah rating will need to be charged (topped up) every ~4 hours. This means that the Tesla vehicle will have to wake up as often as 6 times a day just to top up the 12V lithium battery. This will use more power over a 24 hour period and over the days (weeks) that the Tesla vehicle might be parked.

By comparison the Ohmmu 12V lithium iron phosphate (LFP) replacement battery for the Tesla vehicles that has been available for some time has a higher capacity (40Ah). The Ohmmu battery should be able to run the essential Tesla vehicle systems for almost 24 hours before needing to be recharged (topped up.)
 
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e645824

Member
May 15, 2021
163
217
USA
Super easy "retrofit". No different than any other battery replacement.


The new Model S battery is 15.5 Volts. So the charger has to be at a higher voltage. Typical lead-acid batteries are charged at 14+ volts. Being lithium, the Ohmmu battery runs around 13 Volts. The issue is if the existing Model Y chargers can charge the new 15.5 Volt battery.

In the case of the Ohmmu, this comes from their web page:
Our batteries have a built-in BMS (Battery Management System) which has the ability to "disconnect" internally in the event of a dangerous situation, this includes OVER voltage, OVER temperature and OVER current (shorting of terminals included).
In these scenarios a RESET is needed.
To reset place battery in a cool safe location without anything connected to it for 5 minutes. Then apply 12.0V - 14.8V to terminals. After a few minutes remove the voltage from terminals and check battery voltage again, it should be restored.

So even though the Ohmmu is a drop-in replacement for the OEM lead-acid, it seems that the Model Y system would need to be adjusted (hardware or software or both) to charge the new 15.5 Volt lithium.

Scott

--

MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021
 

MP3Mike

Well-Known Member
Feb 1, 2016
17,237
41,820
Oregon
If the Li-ion 12V battery is rated at 6.9Ah and 15V (as stated in the article in the link) the lithium 12V is going to need to be charged (topped up) more often than the current 12V maintenance free (MF) flooded lead-acid battery (45Ah). The current lead-acid 12V battery can last about a full day powering the Tesla vehicle's essential systems (BT, LTE, alarm system) while the Tesla vehicle is in sleep mode. A 12V lithium battery with a 6.9Ah rating will need to be charged (topped up) every ~4 hours. This means that the Tesla vehicle will have to wake up as often as 6 times a day just to top up the 12V lithium battery. This will use more power over a 24 hour period and over the
But the vehicles with this battery have a constant support feed from the HV pack even when the car is asleep, so it shouldn't need to charge the 15v battery very often.
 

rrolsbe

Member
Feb 18, 2017
312
199
Albuquerque
But the vehicles with this battery have a constant support feed from the HV pack even when the car is asleep, so it shouldn't need to charge the 15v battery very often.
Where did you find the constant support feed while sleeping documented/discussed? Even if the car had to wake up to top off this new 12V battery every four hours and could do so in less than 30 minutes, it would not not use any more power. My 2018 model 3 sleeps for around 17 hours then wakes up for around 2 hours to top off the 12V battery, then rinse and repeat.
 

jcanoe

Active Member
Oct 2, 2020
4,374
4,546
Maryland
If the Tesla Model Y with the 12V (really 15V) lithium battery has to charge this battery every 4 hours for 30 minutes that would be 230W while the Tesla Model Y is awake plus (15V X 10A = 150W) while charging (assuming 10A charging) for roughly ~380W for 30 minutes. Repeating 6 times for 30 minutes over 24 hours the power used would be ~1.14kWh. 1.14kWh/78kWh is ~1.5% of the battery capacity (assuming a full charge) every 24 hours. Instead of 1% battery charge loss for every 6 or 7 days while the Tesla Model Y is parked, in sleep mode without Sentry mode being active, you would lose ~10% per week.
 

jcanoe

Active Member
Oct 2, 2020
4,374
4,546
Maryland
How is the lithium battery better than the lead acid battery? My understanding is lead acid batteries don’t require thermal mgmt. because they are tolerant of wide temperature ranges.
Some claim that the lithium 12V battery will last longer than the current lead-acid battery used in the Tesla Model Y (also Model 3, older S and X.) The 12V lead-acid battery currently used has a reputation for failing at ~2 years, sometimes longer or shorter. The Tesla warranty covers the replacement of the 12V battery for the first 4 years. The Tesla vehicle is designed to notify the vehicle operator when the 12V lead-acid battery needs to be replaced but this feature does not always function as designed.

As far as operating temperatures, lead-acid batteries have a wider operating range. Lithium batteries don't perform at low temperatures (below 0C/32F) and can be damaged if exposed for prolonged periods to high temperatures..
 
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jcanoe

Active Member
Oct 2, 2020
4,374
4,546
Maryland
I read that Li ion batteries shouldn’t be charged below freezing. How does the “topping off” work when it is say -20F in Minnesota?
There would have to be a temperature sensor that would only enable charging when the battery was above 32F. Tesla is able to heat the charge port and the Autopilot/Dashcam cameras so they could also add a heating element underneath the 12V lithium battery to warm the battery in cold weather. There would be no direct way to cool the 12V lithium battery in hot weather, probably not practical to add liquid cooling for the 12V lithium battery.
 
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Sophias_dad

Active Member
Supporting Member
Jul 29, 2018
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Massachusetts
There would have to be a temperature sensor that would only enable charging when the battery was above 32F. Tesla is able to heat the charge port and the Autopilot/Dashcam cameras so they could also add a heating element underneath the 12V lithium battery to warm the battery in cold weather. There would be no direct way to cool the 12V lithium battery in hot weather, probably not practical to add liquid cooling for the 12V lithium battery.
Thermoelectric cooling - Wikipedia works both ways, and has no moving parts unless you want to add a fan.
 
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jcanoe

Active Member
Oct 2, 2020
4,374
4,546
Maryland
What would happen if you plugged in a battery tender? Then the tesla woul not wake up to charge the battery?
You could do that with the current 12V lead-acid battery but a lithium battery would require a different charging voltage, float voltage than a lead-acid battery. Even within the range of different types of lead-acid batteries the different battery types require different charging protocols.
 

mark95476

Active Member
Jun 21, 2020
2,067
1,589
Bay Area CA
:rolleyes:

So you're saying a car doing nothing will be 10x more efficient with a lead-acid battery vs a li-ion? I don't know how you came-up with your assumptions, but they seem half-baked at best.

The lead-acid battery has an larger initial energy reservior. Other than that, energy consumption should be very similar.

If the Tesla Model Y with the 12V (really 15V) lithium battery has to charge this battery every 4 hours for 30 minutes that would be 230W while the Tesla Model Y is awake plus (15V X 10A = 150W) while charging (assuming 10A charging) for roughly ~380W for 30 minutes. Repeating 6 times for 30 minutes over 24 hours the power used would be ~1.14kWh. 1.14kWh/78kWh is ~1.5% of the battery capacity (assuming a full charge) every 24 hours. Instead of 1% battery charge loss for every 6 or 7 days while the Tesla Model Y is parked, in sleep mode without Sentry mode being active, you would lose ~10% per week.

This 12V LFP battery is designed/created by CATL and works at low temps.

Some claim that the lithium 12V battery will last longer than the current lead-acid battery used in the Tesla Model Y (also Model 3, older S and X.) The 12V lead-acid battery currently used has a reputation for failing at ~2 years, sometimes longer or shorter. The Tesla warranty covers the replacement of the 12V battery for the first 4 years. The Tesla vehicle is designed to notify the vehicle operator when the 12V lead-acid battery needs to be replaced but this feature does not always function as designed.

As far as operating temperatures, lead-acid batteries have a wider operating range. Lithium batteries don't perform at low temperatures (below 0C/32F) and can be damaged if exposed for prolonged periods to high temperatures..
 

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