So Why Does the 12V Battery Die?

[dgpcolorado]

Sounds like a poor supplier. Tesla is in the battery business, why don’t they just make their own LiPO 12 volt baattry like this one.

element3batteries

One possibility, suggested by others, is that a Lithium accessory battery might not hold up in very cold weather — I noticed that your link didn't have any temperature range listed in the specs.


If the Model 3 works like the S, the car will warn the driver about a failing battery in plenty of time for it to be taken in for service and the battery replaced. I don't think the OP should be concerned about it. The other thread on the failed 12V battery is likely to be a fluke, perhaps a bad battery to begin with, or a poor ground connection. Unless numerous reports of 12V battery replacements appear, as happened with the early Model S, it doesn't seem to be something to worry about with the Model 3.

 

[Lloyd]

I think eventually they will have a 24V or possibly 48V electrical system. It will save weight in wiring, but all of the accessories and bulbs will have to be redesigned exclusively for the Tesla instead of "off the shelf" automotive parts.
Perhaps we will see this in the 2020 Roadster??

 

[OmidAslani]

For the second time in one week my brand new Model 3 fails to start (randomly).
This car is so unreliable and would not recommend buying it. Leaves wife and child stranded on the road!
Tesla needs to fix this 12V issue now. I need my money back....
Sadly, they do not fix the root cause. Tired of new car (2 weeks old) being towed leaving us without car. Worried this will be an ongoing thing...

 

[snakeopus121]

For the second time in one week my brand new Model 3 fails to start (randomly).
This car is so unreliable and would not recommend buying it. Leaves wife and child stranded on the road!
Tesla needs to fix this 12V issue now. I need my money back....
Sadly, they do not fix the root cause. Tired of new car (2 weeks old) being towed leaving us without car. Worried this will be an ongoing thing...

As I've mentioned before -- I became interested in Tesla back when the MS first came out and have followed the company since then..

Honestly I'm not sure what Tesla is trying to do.....They don't learn from prior mistakes, mess up the simplest things, and certainly are not the cutting edge of any technology....Building a car is obviously not their first priority

The 12V battery issue is just one example of many......

The "phone as key" debacle seriously blew my mind ---- I though the "Falcon Wing Doors" was the worst decision Tesla ever made --- but they proved me wrong....Still don't know how anyone accepts the vinyl seats though.

 

[jamnmon66]

As I've mentioned before -- I became interested in Tesla back when the MS first came out and have followed the company since then..

Honestly I'm not sure what Tesla is trying to do.....They don't learn from prior mistakes, mess up the simplest things, and certainly are not the cutting edge of any technology....Building a car is obviously not their first priority

The 12V battery issue is just one example of many......

The "phone as key" debacle seriously blew my mind ---- I though the "Falcon Wing Doors" was the worst decision Tesla ever made --- but they proved me wrong....Still don't know how anyone accepts the vinyl seats though.

For the record, my Model 3 is the most impressive product of any kind that I've ever purchased, warts and all. If you're just following the complaints in the forums and the media then you have a very skewed window into what's going on.

 

[TEG]

For the record, my Model 3 is the most impressive product of any kind that I've ever purchased, warts and all. If you're just following the complaints in the forums and the media then you have a very skewed window into what's going on.

I have offered some small constructive critiques of my model 3, but so far it has been an overall fantastic vehicle / product.

Just a month in and ~700 miles (so far), but about to do a 1000 mile weekend road trip.
It is the best overall package of a car I have had, combining comfort, sportiness, luxury, convenience, and just generally well executed on so many levels.
I am really appreciating how well the regen braking works. I had some minor concern going in that RWD only regen might be too weak, and I would regret not getting AWD, but the regen slows the vehicle smartly so I can do "one pedal driving" nearly all the time.
Even with my "lead foot" tendencies from stop to stop, I can just let regen pull me back down before the next stop. The acceleration and regen braking is so smooth and predictable, that it makes driving anything else seem uncivilized.

Long term will tell if reliability is good enough to call this car great, and I sure hope it holds up well because I don't want this party to stop.

 

[Fusion]

I agree, once you drive a Tesla, it's hard to go to any other car. I've tried other electric cars and they are nothing like a Tesla.

 

[int32_t]

...They don't learn from prior mistakes, mess up the simplest things, and certainly are not the cutting edge of any technology...

Your posts suddenly took a turn to the negative, so I just want to point out that this was specifically addressed in @gregd's post, above:

But, some of the newer cars - I think from the Refresh forward - have a small DC-DC converter inside the main battery pack, where it can provide some part of the 12 v system's power. This limits the cycling stress on the 12v battery. So with this change, the car shouldn't be doing deep cycles of the 12v battery, and they should last a long time.

Given this evidence (and many others, including build quality improvements over the years, etc), Tesla is always learning and improving things that were admittedly broken in the original manifestation.

 

[MaryAnning3]

For the second time in one week my brand new Model 3 fails to start (randomly).
This car is so unreliable and would not recommend buying it. Leaves wife and child stranded on the road!
Tesla needs to fix this 12V issue now. I need my money back....
Sadly, they do not fix the root cause. Tired of new car (2 weeks old) being towed leaving us without car. Worried this will be an ongoing thing...

I am sorry for your problems. I think your car is an extreme outlier. My 3 is 100% reliable. How are things now? Did your problems get fixed? What was the origin of your troubles?

 

[Xenoilphobe]

It dies due to excessive cycles and the nature of lead acid batteries. go with lithium when you replace it. I did this on all three of my Model S's and never had an issue since. I'm at 90K on my oldest Model S and it's still rolling with the same battery that they shipped directly to the Tesla SC for install and replacement of the original that died at about 33K. Lead acid only has about 1000 full charge cycles of life and LiFePo has more like 2500 full charge cycles before it degrades, so rule of thumb it should last 2.5 time longer than your Lead Acid OEM battery.

Also electronic components usually fail fast and early, once replaced with a known good part, it will last a long time....

https://www.ohmmu.com/shop


https://www.amazon.com/12V-Lithium-Battery-Tesla-Model/dp/B07K4SCB1Y

 

[ecarfan]

I’ve owned four Teslas. Leaving aside the Roadster (mine was a 1.5 and had no separate 12V battery) my 2013 S needed one new 12V battery after a year of ownership (known issue with the early S cars, the car alerted me in advance of failure, Mobile Service replaced it, the car never failed me in 62K miles), my 2 year old X with 38K miles has not needed a new 12V battery and has never failed to get me to where I wanted to go, and my 3 with 13K miles has had no 12V battery issues and has had zero significant issues (no failures, turn signal unit replaced, forward window trim piece replaced, nothing else).

 

[sduck]

I am sorry for your problems. I think your car is an extreme outlier. My 3 is 100% reliable. How are things now? Did your problems get fixed? What was the origin of your troubles?

You replied to a one time poster, who posted that 16 months ago - I doubt they'll see it.

My 12v battery died, suddenly, at about 10 months in, a few months ago. At that age, I can only assume it was a fluke, just a crummy battery. Tesla SC nearby fixed it the next morning for free, warranty repair. They said that this is a really rare problem.

 

[Xenoilphobe]

One possibility, suggested by others, is that a Lithium accessory battery might not hold up in very cold weather — I noticed that your link didn't have any temperature range listed in the specs.

Source: https://www.ohmmu.com/battery-testing
Thermal chambers allow simulation of extreme heat and extreme cold conditions. Our in-house Thermotron chamber allows us to push the envelope with capabilities of reaching down to -70° Celsius (-94° F) on the low side and up to 185° Celsius (365° F) on the high side. Testing has been performed on all products we sell (per IEC 60068-2-1) so we can stand behind our batteries 100%.

Vibration Simulators allow us to subject batteries to IEC 60068-2-64 standardized testing, which is the OEM automotive-grade standard used to ensure longevity and durability of components. This testing subjects components to up to 60hrs of testing at frequencies between 10 and 1000 Hz. We perform vibration testing after doing temperature stress testing on batteries to ensure they are safe for operation in vehicles throughout the life of the battery.

Charge, Discharge and Cycle testing machines allow simulations of variable loads which are representative of battery conditions during operation. We have equipment which allows us to test 12V batteries with currents exceeding 100A continuously for both Charging and Discharging. To simulate life-cycles and gauge degradation rates we are able to perform continuous cycle testing which pushes batteries from 0% to 100% to 0% ad infinitum. We perform various load and cycle testing protocols during deep cold, extreme heat and vibration simulations to ensure performance in real-life applications.

If the Model 3 works like the S, the car will warn the driver about a failing battery in plenty of time for it to be taken in for service and the battery replaced. I don't think the OP should be concerned about it. The other thread on the failed 12V battery is likely to be a fluke, perhaps a bad battery to begin with, or a poor ground connection. Unless numerous reports of 12V battery replacements appear, as happened with the early Model S, it doesn't seem to be something to worry about with the Model 3.

 

[MaryAnning3]

You replied to a one time poster, who posted that 16 months ago - I doubt they'll see it.

My 12v battery died, suddenly, at about 10 months in, a few months ago. At that age, I can only assume it was a fluke, just a crummy battery. Tesla SC nearby fixed it the next morning for free, warranty repair. They said that this is a really rare problem.

Thanks. I thought it might appear in their alerts or something. True, it is kind of a long shot.

 

[vickh]

Tesla used to put a lot of cycles on the 12V battery. They charged it from the HV battery then let it run down and then charged it back up, over and over. With a fairly significant load even when the car was "off". That doesn't seem easy on the battery.

The newer cars have something I guess is closer to a trickle charger and should be easier on the 12V battery.

Are they lithium ion also? If not maybe when I replace. Az heart kills batteries fast

Also do the tricks to increase range such as turning off Wi-Fi help the 12-volt battery as well, because of computer sleeping

 

[int32_t]

Are they lithium ion also? If not maybe when I replace. Az heart kills batteries fast

Also do the tricks to increase range such as turning off Wi-Fi help the 12-volt battery as well, because of computer sleeping

The 12V battery in all of Tesla’s vehicles is a lead-acid battery, similar to the ones in ICE vehicles. They’re not quite the same as ICE lead-acid batteries as they’re optimized for cycle life, not cranking amps, so that’s why Tesla says not to try boosting an ICE car with a Tesla.

Turning off Wi-Fi shouldn’t have much, if any, effect. The 12V battery is constantly maintained by the HV battery. Tesla has made thousands of Model 3s, and if the 12V battery was a problem (outside of some isolated incidents due to individual parts), we’d be hearing more about it.

 

[marknei]

The 12V battery in all of Tesla’s vehicles is a lead-acid battery, similar to the ones in ICE vehicles. They’re not quite the same as ICE lead-acid batteries as they’re optimized for cycle life, not cranking amps, so that’s why Tesla says not to try boosting an ICE car with a Tesla.

Turning off Wi-Fi shouldn’t have much, if any, effect. The 12V battery is constantly maintained by the HV battery. Tesla has made thousands of Model 3s, and if the 12V battery was a problem (outside of some isolated incidents due to individual parts), we’d be hearing more about it.

Seems that is settled. Now on to my bigger (well, to me anyway) question: I got my Tesla in August. ( My previous car had tires that needed air every few weeks and to deal with that I bought a high capacity 12v DC pump. It draws too much current to use a "lighter socket" to get 12V DC, so it has clips that attach directly to the 12v battery. It also has its own fuse rated at 30 amps DC, and yes, it did blow a couple of times, and I had to track down a short to use the pump again) I would like to use this pump again to put air in my Model 3's tires, but I am concerned about the pump draining the 12V battery and leaving me stranded. Am I correct in saying that I don't have to worry about this, because the 12V battery will recharge from the traction battery or do I have to buy a different pump?

Thanks for any insight,
Mark

 

[ngogas]

Maybe this is why they say a plug in Tesla is a happy Tesla. As I assume it also charges this 12v battery.

 

[Xenoilphobe]

Seems that is settled. Now on to my bigger (well, to me anyway) question: I got my Tesla in August. ( My previous car had tires that needed air every few weeks and to deal with that I bought a high capacity 12v DC pump. It draws too much current to use a "lighter socket" to get 12V DC, so it has clips that attach directly to the 12v battery. It also has its own fuse rated at 30 amps DC, and yes, it did blow a couple of times, and I had to track down a short to use the pump again) I would like to use this pump again to put air in my Model 3's tires, but I am concerned about the pump draining the 12V battery and leaving me stranded. Am I correct in saying that I don't have to worry about this, because the 12V battery will recharge from the traction battery or do I have to buy a different pump?

Thanks for any insight,
Mark

Here is another option and one of my favorite tools - I already have the Ryobi 18volt batteries for other tools, so I got just the pump without the charger and battery and yes the traction or HVB: high voltage battery will "tender" the LVB: low voltage battery through the cars integrated inverter.

BTW I just had to change out my wife's 2016 Model S 90D LVB (14.4 volt) with 48,000 miles on it. Took me about an hour to pull the old battery and install in the new OHMMU battery, which was significantly lighter.

 

[FlatSix911]

Seems that is settled. Now on to my bigger (well, to me anyway) question: I got my Tesla in August. ( My previous car had tires that needed air every few weeks and to deal with that I bought a high capacity 12v DC pump. It draws too much current to use a "lighter socket" to get 12V DC, so it has clips that attach directly to the 12v battery. It also has its own fuse rated at 30 amps DC, and yes, it did blow a couple of times, and I had to track down a short to use the pump again) I would like to use this pump again to put air in my Model 3's tires, but I am concerned about the pump draining the 12V battery and leaving me stranded. Am I correct in saying that I don't have to worry about this because the 12V battery will recharge from the traction battery or do I have to buy a different pump?

Thanks for any insight,
Mark

The short answer is yes... your 12V battery will be continuously recharged by the 400V traction battery.

You can also attach a 2000W inverter to your 12V battery if you want a constant 120V power supply.

Is it safe to connect a large inverter to the 12V battery?