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Lithium 12v battery.

Vin_L

Member
Apr 24, 2021
211
342
San Jose, CA
Just wondering if anyone has changed out there 12v battery to a lithium? Seems like I’m seeing a lot of dead vehicles in the middle of a trip due to a faulty 12v. I’ve had my MY for 2 months now. The only thing that worries me with this car is having the 12v die as I’m cruising down the road. Anyone else change it out just for the hell of it?
 
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glide

Active Member
Jun 6, 2018
4,161
5,840
USA
Just wondering if anyone has changed out there 12v battery to a lithium? Seems like I’m seeing a lot of dead vehicles in the middle of a trip due to a faulty 12v. I’ve had my MY for 2 months now. The only thing that worries me with this car is having the 12v die as I’m cruising down the road. Anyone else change it out just for the hell of it?
Probably not a great idea to stuff a lithium battery in a vehicle that was not designed for it. What happens when it gets too cold for the battery to start the car?
 

Vin_L

Member
Apr 24, 2021
211
342
San Jose, CA
Probably not a great idea to stuff a lithium battery in a vehicle that was not designed for it. What happens when it gets too cold for the battery to start the car?
My understanding is they have a 3rd party battery designed for the car? Plus living in CA it never really gets too cold.
 

glide

Active Member
Jun 6, 2018
4,161
5,840
USA
My understanding is they have a 3rd party battery designed for the car? Plus living in CA it never really gets too cold.
Temp is only one factor when considering a lithium replacement.

The other is obviously voltage. A fully charged Li battery puts out about 14.7 volts. The typical vehicle electrical system is run off a 12v source. You would likely need a DCtoDC charger to regulate the voltage.

Point being, lithium batteries are not a drop in replacement and could cause serious issues with your electrical system, and most definitely would void your warranty.
 

LoudMusic

Member
Jul 21, 2020
844
911
Arkansas
LoudMusic: Do you have info that explains how the charging system of the current Model Y can accommodate a lithium battery?

It is my understanding that the charging parameters for the lithium battery are different, so it IS NOT a simple "drop in" replacement.

I don't, and it's true the charging curve is a little different. I suspect Ohmmu explain it on their website.

Lead acid batteries have a nearly linear voltage drop as they are discharged, but lithium batteries stay much more level voltage through the majority of their capacity. I doubt the car knows how to take that into consideration. My guess would be that the default charging profile in the cars keeps them in "float" until the battery gets down to something like 11.5v and then goes into "bulk" until they hit something like 13.5v to 14v. That's fairly common for lead acid, maybe a bit low, but would also accommodate the lithium battery without any issue.

The main problem I'm aware of is trying to charge lithium batteries from an underpowered alternator and burning up the alternator. Teslas don't have that problem because they don't have alternators.
 

jcanoe

Active Member
Oct 2, 2020
4,332
4,495
Maryland
Just wondering if anyone has changed out there 12v battery to a lithium? Seems like I’m seeing a lot of dead vehicles in the middle of a trip due to a faulty 12v. I’ve had my MY for 2 months now. The only thing that worries me with this car is having the 12v die as I’m cruising down the road. Anyone else change it out just for the hell of it?
The Tesla Model Y 12V battery seems to last ~2 years in typical service. The Tesla vehicle is designed to notify the driver when the 12V battery needs to be replaced, i.e. you should have several weeks notice that the 12V requires replacing. I keep a small 12V lithium jump starter at home and for trips. I can use the jump starter to pop the hood, access the 12V battery and power on the Tesla vehicle. Once the Tesla vehicle is powered on all 12V power comes from the DC-to-DC converter. If you get the 12V battery needs to be replaced warning just leave Sentry mode active and the Model Y will not enter sleep mode. Do this until the 12V can be replaced.
 

glide

Active Member
Jun 6, 2018
4,161
5,840
USA
Drop in replacement. Tesla Lithium 12v | Ohmmu | United States

All batteries have a voltage curve. All electronics have a range of acceptable voltage.

Tesla is changing to lithium 12v batteries as well. Tesla to replace SLI lead-acid batteries with 12V lithium-ion in new EVs | www.bestmag.co.uk
Drop in replacement. That’s according to the vendor of the product. Not Tesla. Take it with a grain of salt.

And yes, Tesla may be planning to switch over to lithium but they aren’t just going to be swapping batteries. There is a lot more involved than that.
 

jcanoe

Active Member
Oct 2, 2020
4,332
4,495
Maryland
Purchase a small lithium ion jump starter pack for peace of mind. I have an older model DB Power jump starter. I have used my DP Power jump starter to jump start someone's Chevrolet ICE vehicle that would not start one cold night. The DB Power unit worked as advertised. Now I keep the jump starter at home or in the Tesla (except in summer because of the high temperatures) and for trips. (Note: If you are going on a trip bring the jump starter. When you arrive take the jump starter out of the vehicle, keep it with you. If you leave the jump starter in the Tesla and the Tesla is locked you won't be able to open the vehicle if the 12V battery fails.)

Amazon.com: DBPOWER 800A 18000mAh Portable Car Jump Starter (up to 7.2L Gas, 5.5L Diesel Engine) Battery Booster with Smart Charging Port, Compass, LCD Screen and LED Light (Black/Red): Automotive

You can spend more or less, I have had good success with the DB Power unit I own.
 
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LoudMusic

Member
Jul 21, 2020
844
911
Arkansas
Drop in replacement. That’s according to the vendor of the product. Not Tesla. Take it with a grain of salt.

And yes, Tesla may be planning to switch over to lithium but they aren’t just going to be swapping batteries. There is a lot more involved than that.

Eh, there's not "a lot more" to it, but they'll probably change the charging curve. A couple minor tweaks of the voltages used to push power into the 12v battery. The lead acid charging curve would probably work fine, but it could be improved.
 

glide

Active Member
Jun 6, 2018
4,161
5,840
USA
Eh, there's not "a lot more" to it, but they'll probably change the charging curve. A couple minor tweaks of the voltages used to push power into the 12v battery. The lead acid charging curve would probably work fine, but it could be improved.
What 12v battery? The lithium battery would replace it. Then how do you regulate the voltage for the rest of the electrical system?

People who are saying this is a drop in have very obviously never converted anything from 12v lead acid to lithium.

And what is the point of a lithium battery when it is only charged to 12v?
 

brkaus

Well-Known Member
Jul 8, 2014
8,256
6,822
Austin, TX
I don’t believe the 6 month failure rate is very high. Ours failed just over 2 years.

I’m going to spend $85 in another 2 years and proactively replace it. It’s super easy. It was also super easy to “jump start”.

I personally don’t see a lot of benefit in a 3rd party li-ion battery vs the risks of Tesla blaming it for something.
 
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LoudMusic

Member
Jul 21, 2020
844
911
Arkansas
What 12v battery? The lithium battery would replace it. Then how do you regulate the voltage for the rest of the electrical system?

People who are saying this is a drop in have very obviously never converted anything from 12v lead acid to lithium.

And what is the point of a lithium battery when it is only charged to 12v?

Why would it only be charged to 12v? The lead acid battery charges to 13.5v+. The existing 12v battery charger in the car would raise the lithium battery to at least that amount.

To charge a battery you have to supply higher voltage than the battery's existing voltage. And intelligent battery charger measures the battery's voltage then supplies the correctly increased voltage in order to raise the voltage of the battery.
 

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