12v spare?

[father_of_6]

I have a service appointment next week and was considering buying a 12v battery while there as a backup. My Model 3 is 2.5 years old.

The service center is a 1.5 hour drive, and when the battery does die it'd be a whole lot easier if I had a spare already.

Has anyone else done this? Is it bad for the spare 12v to sit around in my garage for "who knows how long"? Don't want to buy it just to have it die from sitting idle.

 

[Supcom]

I have a service appointment next week and was considering buying a 12v battery while there as a backup. My Model 3 is 2.5 years old.

The service center is a 1.5 hour drive, and when the battery does die it'd be a whole lot easier if I had a spare already.

Has anyone else done this? Is it bad for the spare 12v to sit around in my garage for "who knows how long"? Don't want to buy it just to have it die from sitting idle.

The average battery lasts about 3-5 years, so, if you are concerned about your current battery failing, perhaps it would be best to just have it replaced while you are at the SC. Otherwise, should you wait for your current battery to die, your spare might be 2.5 years old at that point. The 12V battery does not get heavily taxed like an ICE vehicle's battery, so most degradation is likely due to age, as opposed to usage.

If you do buy a spare, you will also need to keep it charged. Keeping the battery on a trickle charger will likely cost between $15 and $20 per year in electricity. Add the cost of the charger, if you don't have one already.

Assuming that you have no readily available transportation to the SC in the event your battery fails without warning, you might consider just proactively replacing it now.

 

[father_of_6]

If you do buy a spare, you will also need to keep it charged. Keeping the battery on a trickle charger will likely cost between $15 and $20 per year in electricity. Add the cost of the charger, if you don't have one already.

That's the information I was after. Do I actually *need* to keep it charged? The ones sitting in Walmart aren't kept on a charger.

I don't want to replace it prematurely either... it's just not in my personality to pay to replace a battery that's still working. If the average battery lasts 3-5 years, I could be only halfway through the life of mine. I'd just rather have the replacement in my possession before my existing one dies.

 

[Supcom]

That's the information I was after. Do I actually *need* to keep it charged? The ones sitting in Walmart aren't kept on a charger.

I don't want to replace it prematurely either... it's just not in my personality to pay to replace a battery that's still working. If the average battery lasts 3-5 years, I could be only halfway through the life of mine. I'd just rather have the replacement in my possession before my existing one dies.

The ones at Walmart are not expected to sit around for a year or more before they are purchased. You could let the battery sit. It will self-discharge about 5% per month, so should be recharged every six months, or so. But, not having the battery fully charged leads to lead sulphite forming on the plates, which will degrade the battery. So, it should be kept charged, if possible.

Keep in mind that having the spare would protect you only from a sudden failure of the battery. Your car does monitor the battery health and normally will notify you of the need to replace the battery before it becomes unusable. But, batteries do fail unexpectedly.

And, chance are pretty good that a sudden failure will occur when you are away from home, invalidating all your preparedness. That is, unless you plan to keep the spare in the frunk.

 

[Tdriver]

There is a very good chance that your battery could die anytime now, especially after 2 1/2 years. If it dies you are locked out of the car and the only way to get in is through the 12 V connection at the front of the car if you have a 12 V source to use.. I have had three batteries die at the age of two or 2 1/2 years.

 

[beatle]

You should get a warning when the battery is starting to go. The 12v battery on my 2015 lasted almost 6 years, and the one in my 2019 is almost 4 years old already. I would not buy a battery for it to just sit around.

 

[father_of_6]

Maybe the weather in CA vs VA makes all the difference in 12v longevity. I guess I'll just wait it out and take my chances.

 

[Du30]

Tesla will now send push notifications when 12V battery needs to be replaced

Tesla is sending out push notifications to owners who need to replace their 12V battery, which powers lights, wiper motors, ABS electronics, display, and more.

www.notateslaapp.com

 

[dhrivnak]

That's the information I was after. Do I actually *need* to keep it charged? The ones sitting in Walmart aren't kept on a charger.

I don't want to replace it prematurely either... it's just not in my personality to pay to replace a battery that's still working. If the average battery lasts 3-5 years, I could be only halfway through the life of mine. I'd just rather have the replacement in my possession before my existing one dies.

Mine went 4 years before I got the warning. Not hard to replace with a battery from at a local parts store. As mine happened on a Saturday morning JUST before a 4000 mile trip on Sunday.

 

[NewbyMaybe]

Good to know there's a simple alternative. Year of your car? Battery model number?

 

[oldsport]

pics?

 

[ATPMSD]

If you wait until it needs to be replaced it is a warranty item and will be replaced for free.

 

[theothertom]

I don't want to replace it prematurely either

Might want to re-think that. Despite Tesla's best efforts, sometimes batteries die without warning. You'll be stranded if that happens. You can't even unlock the car.

 

[ATPMSD]

Might want to re-think that. Despite Tesla's best efforts, sometimes batteries die without warning. You'll be stranded if that happens. You can't even unlock the car.

You need to know how to open the Frunk manually (or with a small A23 battery)!

And this is why I carry a jumper. Once the car is awake it is drivable, and if you leave Sentry On (and disable any exceptions) the car will not go to back to sleep.

Amazon.com : Battery jumper

 

[father_of_6]

Might want to re-think that. Despite Tesla's best efforts, sometimes batteries die without warning. You'll be stranded if that happens. You can't even unlock the car.

Therein lies the problem. I certainly want to replace the battery before it dies and leaves me stranded (if not at home), however I don't know when the right time to do that is.

Some people have stated they got 5 years out of their battery, and some only 2. It *seems* that those in very hot climates have shorter 12v battery life... so I might be in the 5 year camp.

Do I replace it annually to avoid the inconvenience? I have to drive 1.5 hours to get to the service center just to get the battery. Do I replace it every 2 years if it might last 5? Every 3 years? What's the right threshold?

 

[NewbyMaybe]

Regular maintenance: Put a cheap slow charger on the 12v now and then, especially before parking the car for more than a few days.

 

[theothertom]

Do I replace it annually to avoid the inconvenience? I have to drive 1.5 hours to get to the service center just to get the battery. Do I replace it every 2 years if it might last 5? Every 3 years? What's the right threshold?

I'd replace it at 3 year intervals. The mobile tech will come to your house and do it for you.

 

[theothertom]

You need to know how to open the Frunk manually (or with a small A23 battery)!

Yes, you can open it with an A23 battery if you know how to do it. And if you have an A23 battery.
I've never tried but I suppose you could open it with the jumper cables if you know how to do it.

 

[theothertom]

Once the car is awake it is drivable

I'm not sure it would be drivable if it has a dead battery. If the battery is really dead, I don't think a jumper from another car would revive it.
I recommend replacing the 12V proactively to avoid the hassle.

 

[ATPMSD]

Yes, you can open it with an A23 battery if you know how to do it. And if you have an A23 battery.
I've never tried but I suppose you could open it with the jumper cables if you know how to do it.

Plenty of how to videos on this Including where to store it. And yes, a standard set of jumper cables will also work, but it will only open the frunk. You must connect directly to the battery for the car to wake up.