Near annual replacement of 12V battery is typical according to Tesla Service Tech

[JRP3]

The other question I can't help but ask ... if the Telsa stays plugged in when it is home, why is it that the car doesn't keep the 12V topped off completely?

As I understand it to keep the DC/DC from always running it allows the 12V battery to cycle down to some voltage level before engaging regardless if it's plugged in to the mains or not. From an energy use standpoint this is more efficient, unfortunately the cycling kills the 12V battery faster than keeping it at a constant 13V trickle charge.

 

[Rocky_H]

Putting a trickle charger on it has been done, and it does work perfectly. Someone did that and monitored the car with VisibleTesla. It covered the vampire usage, and the recharging cycle of DC to DC never came on.

Any reason not to hook up a battery tender to the 12 volt battery ?

 

[Cottonwood]

Putting a trickle charger on it has been done, and it does work perfectly. Someone did that and monitored the car with VisibleTesla. It covered the vampire usage, and the recharging cycle of DC to DC never came on.

Any reason not to hook up a battery tender to the 12 volt battery ?

The BIG issue is that the charger needs to be a smart, multi-stage charger with a total output of 4 Amps or more. That is way more than a trickle, because the Vampire is very thirsty!

 

[Steve S]

I visited the Villa Park SC today for a new battery. Great team working there. They just received a shipment of Model X's in so I got to see them in many color combos. That new white interior is actually quite gorgeous.

 

[ZBB]

I'm glad it happened today instead of next week when I have a cross country trip planned. Calling Tesla tomorrow but my nearest SC is 3 hours away.

I also got the 12V message this week, and we also have an upcoming road trip (which will be off the Supercharger network too...). They first said that they didn't have any service slots avail until after the trip -- but I pressed and was able to get one a couple days before we go.

This will be my 2nd replacement in not quite 3 years. The original was replaced during one of the scheduled service visits a bit over a year ago. Interesting about the 12v cycling more when the car is not driven -- I had work trips for 3 weeks in Feb, so the car sat for most of the month.

 

[Steve S]

I also got the 12V message this week, and we also have an upcoming road trip (which will be off the Supercharger network too...). They first said that they didn't have any service slots avail until after the trip -- but I pressed and was able to get one a couple days before we go.

This will be my 2nd replacement in not quite 3 years. The original was replaced during one of the scheduled service visits a bit over a year ago. Interesting about the 12v cycling more when the car is not driven -- I had work trips for 3 weeks in Feb, so the car sat for most of the month.

thats interesting as I really didn't drive my car that often this winter. I'm sure sitting (always plugged in though) didn't help that 12V. That actual time it took them to change my battery was probably around 20 minutes.

We are now considering taking the wife's new Bimmer as charging options south of Tampa are a rarity. At least in the area we will be at. I was looking forward to the trip in the MS, but at the same time, I'm cutting about 8 hours or so off of the trip in charging. We still haven't fully decided though.

 

[chriSharek]

We are now considering taking the wife's new Bimmer as charging options south of Tampa are a rarity. At least in the area we will be at. I was looking forward to the trip in the MS, but at the same time, I'm cutting about 8 hours or so off of the trip in charging. We still haven't fully decided though.

Did you look at destination chargers also? There are a ton out there - and more growing every day. Just another thought. Best of luck on your trip in FL!

I can't wait to take a trip to the Keys now that there is an SC in Marathon! That'll be my summer trip this year!

 

[jerry33]

Did you look at destination chargers also? There are a ton out there - and more growing every day. Just another thought. Best of luck on your trip in FL!

I can't wait to take a trip to the Keys now that there is an SC in Marathon! That'll be my summer trip this year!

The lack of one SC shouldn't stop you. For the first two years of ownership the closest SC was about 1500 miles and we took plenty of over 1000 miles road trips and had a great time.

 

[Steve S]

Did you look at destination chargers also? There are a ton out there - and more growing every day. Just another thought. Best of luck on your trip in FL!

I can't wait to take a trip to the Keys now that there is an SC in Marathon! That'll be my summer trip this year!

I did indeed and the nearest HPWC is a good 40 minute drive away etc in the Sarasota area. There isn't anything close by. I don't think plugging into their available 120 will support even daily quick drives. I haven't ruled it out yet, but I'm stuck in the middle on the decision. Really want to take the MS as well.

 

[AB4EJ]

I know the point I am about to make has been addressed before, but in light of what Ingineer is about to test .... If you're going to pull the battery, why wouldn't you just put a trickle charger on it? I know that we shouldn't need a trickle charger, as the traction battery should do that ... but either 1) it isn't or 2) it is, and the deep discharges that are happening kill the battery off in < 1 year anyway. If it is (#1), and the problem is deep discharges while driving, then taking out the battery shouldn't help, no? If the traction battery isn't adequately 'trickling' to the 12V (#2), then a trickle charge should work at least as well as removing the battery. No? The other question I can't help but ask ... if the Telsa stays plugged in when it is home, why is it that the car doesn't keep the 12V topped off completely? Is the process of 400V -> 12V inefficient, or does this type of battery get damaged by too frequent charging? And if the 400V -> 12V is inefficient, why can't it take the power from 120V of your electrical service to trickle the battery directly (like a trickle charger does?)

I'm thinking about when you have to park the car where a trickle charger is not an option (typical airport) - but other posts suggest that locking the car will be a problem if the 12v battery is not connected.

 

[Ingineer]

I'm thinking about when you have to park the car where a trickle charger is not an option (typical airport) - but other posts suggest that locking the car will be a problem if the 12v battery is not connected.

You can lock it, in fact, w/o power the car definitely stays locked. It's the unlocking that's a problem!

 

[jerry33]

I'm thinking about when you have to park the car where a trickle charger is not an option (typical airport) - but other posts suggest that locking the car will be a problem if the 12v battery is not connected.

Some have 110V that you can plug into. That's more than enough for airport parking.

 

[John Stuckey]

BTW, it's a simple matter to keep the 12v outlet in the console live all the time if desired. It's just a simple relay in fuse box #2 (the one on the passenger side under the removable cowling cover - see owners manual). Simply make up a jumper consisting of short piece of 14AWG or better wire with a couple of male 1/4" spade terminals. Pull the front most passenger side relay out and insert the jumper into the now exposed 1/4" female receptacles, and you're done, the 12v outlet is now on all the time. You can quickly change it back anytime by removing the jumper and reinstalling the relay.[/QUOTE]

Thank you very much for the12v outlet tip! I really appreciate it.
John

 

[BozieBeMe2]

Some have 110V that you can plug into. That's more than enough for airport parking.

I have read somewhere,, that the 12v battery is only charged from the traction battery and therefore cannot be charged by back feeding thru the 12v power outlet in the car's cabin.
This is one of the problems with a cold soaked car being able to "pull" in the12v powered contactors, which are needed to engage the traction battery and also, being able to re-charge the 12v battery from said traction battery.
A true 'Catch 22" scenario.
Once the 12v battery is too weak from age or extreme cold, it will drop to a point of no return - thus total failure.

Plus, I believe that the battery post to the 12v battery have been removed from under the front nose cone. ((late 2015))
Once upon a time there was a way you could place a trickle charger on these post and help keep the 12v systems battery from totally stranding you.
If you were stranded with the dreaded 12v error, you could attach a jump start box on the posts and therefore, get the contactors to allow you to engage the traction battery. Once engaged, it could replenish the 12v and allow you to drive the car!!!
You will still need to service the car but at least you could drive it to the SC.

 

[jerry33]

I have read somewhere,, that the 12v battery is only charged from the traction battery and therefore cannot be charged by back feeding thru the 12v power outlet in the car's cabin.
This is one of the problems with a cold soaked car being able to "pull" in the12v powered contactors, which are needed to engage the traction battery and also, being able to re-charge the 12v battery from said traction battery.
A true 'Catch 22" scenario.
Once the 12v battery is too weak from age or extreme cold, it will drop to a point of no return - thus total failure.

Plus, I believe that the battery post to the 12v battery have been removed from under the front nose cone. ((late 2015))
Once upon a time there was a way you could place a trickle charger on these post and help keep the 12v systems battery from totally stranding you.
If you were stranded with the dreaded 12v error, you could attach a jump start box on the posts and therefore, get the contactors to allow you to engage the traction battery. Once engaged, it could replenish the 12v and allow you to drive the car!!!
You will still need to service the car but at least you could drive it to the SC.

My car has the jumper terminals although I've never had to use them. However, for long term airport parking if you are plugged into 110V this should never be a problem. The good news is that if the 12V battery is weak, there will be a replace battery message on the dash, so in most cases you should get plenty of warning. There have been reports of failure with no warning message, but I haven't seen one of those for some time so perhaps they've improved the software in this area.

 

[Cyclone]

I have read somewhere,, that the 12v battery is only charged from the traction battery and therefore cannot be charged by back feeding thru the 12v power outlet in the car's cabin.
This is one of the problems with a cold soaked car being able to "pull" in the12v powered contactors, which are needed to engage the traction battery and also, being able to re-charge the 12v battery from said traction battery.
A true 'Catch 22" scenario.
Once the 12v battery is too weak from age or extreme cold, it will drop to a point of no return - thus total failure.

Plus, I believe that the battery post to the 12v battery have been removed from under the front nose cone. ((late 2015))
Once upon a time there was a way you could place a trickle charger on these post and help keep the 12v systems battery from totally stranding you.
If you were stranded with the dreaded 12v error, you could attach a jump start box on the posts and therefore, get the contactors to allow you to engage the traction battery. Once engaged, it could replenish the 12v and allow you to drive the car!!!
You will still need to service the car but at least you could drive it to the SC.

Both of these assertions are incorrect. You can trickle the 12v through the cigarette lighter, if you change the lighter to be unswitched instead of switched. There are posts about that.

The jump posts are still there, even on refreshed Model Ss. It may have moved slightly to enable the refresh though. There is now a pull strap in place to get to the jump post.

 

[Vic4Model3]

FWIW, I have a refreshed S and while waxing it over a 3 hour period, the dc-dc 12V charger come on 3 times for about 30 seconds each time. The cooling fan of the dc-dc charger was it's Tell.
Also, opening any of the doors will start the 12V dc-dc charger. Hope the 12V battery lasts a long time, with this design.

 

[BozieBeMe2]

Both of these assertions are incorrect. You can trickle the 12v through the cigarette lighter, if you change the lighter to be unswitched instead of switched. There are posts about that.

The jump posts are still there, even on refreshed Model Ss. It may have moved slightly to enable the refresh though. There is now a pull strap in place to get to the jump post.

Thanks for the heads up, I did find the info on the 12v power connector, Sorry, I know it's bad manners to not acknowledge the original OP, but here it is:
"It's a simple matter to keep the 12v outlet in the console live all the time if desired. It's just a simple relay in fuse box #2 (the one on the passenger side under the removable cowling cover - see owners manual). Simply make up a jumper consisting of short piece of 14AWG or better wire with a couple of male 1/4" spade terminals. Pull the front most passenger side relay out and insert the jumper into the now exposed 1/4" female receptacles, and you're done, the 12v outlet is now on all the time. You can quickly change it back anytime by removing the jumper and reinstalling the relay".

As to the jump posts, I'm glad to hear they are still there, again, I should have kept the OP's name for that tip!

 

[Cyclone]

Thanks for the heads up, I did find the info on the 12v power connector, Sorry, I know it's bad manners to not acknowledge the original OP, but here it is:
"It's a simple matter to keep the 12v outlet in the console live all the time if desired. It's just a simple relay in fuse box #2 (the one on the passenger side under the removable cowling cover - see owners manual). Simply make up a jumper consisting of short piece of 14AWG or better wire with a couple of male 1/4" spade terminals. Pull the front most passenger side relay out and insert the jumper into the now exposed 1/4" female receptacles, and you're done, the 12v outlet is now on all the time. You can quickly change it back anytime by removing the jumper and reinstalling the relay".

As to the jump posts, I'm glad to hear they are still there, again, I should have kept the OP's name for that tip!

No worries. Things change so frequently, it's easy to lose track. I know I have at times!

 

[Ingineer]

FYI: I am the OP that posted how to make the +12v cig lighter port hot all the time.

As I mentioned, the Gateway checks the 12v system voltage every hour, and if it's low, it enters support mode to recharge the 12v AGM battery. You'll know this when you hear the "clunk CLACK" of the main contactors closing to energize the HV system. The cooling pumps will also come on low as the DC-DC converter is liquid cooled.