Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

How and when does the 12v battery get charged?

This site may earn commission on affiliate links.
Any updates on this?

I plan to head out this weekend to go car-camping with a powered cooler/freezer. It has built in “battery protection” which I plan to use in the lowest setting in hopes the the DC-DC Charger will top of the car’s AGM before the cooler shuts off...

GO Series

I will probably use the 12v extension cable it comes with to keep the cooler powered and outside of the vehicle during the day (where I assume it will be more temperate).

I always keep the cabin overheat protection on so based on this thread I hope that’s enough to keep the 12v outlet on continuously. I would guess the cooler uses no more than ~30Wh between the compressor cycling on/off.
Camp Mode will definitely keep the power running to the 12v connector and the USB ports. You access Camp Mode in the same manner that you access Dog Mode.

The problem is that you now have the A/C running after activating Camp Mode. Is it possible to have Camp Mode on (allowing you to power stuff), without the climate system engaged? Something to test out later today, I guess.
 
Sentry mode should keep the 12V on all the time. It seems that some of the recent software keeps the 12V on all the time, even without Sentry mode. So, should be ok. You don't need to keep the climate control on. I would keep cabin overheat protection on all the time, since it is probably keeping our screens from being destroyed.
 
  • Like
Reactions: Itsuo-DC
Camp Mode will definitely keep the power running to the 12v connector and the USB ports. You access Camp Mode in the same manner that you access Dog Mode.

The problem is that you now have the A/C running after activating Camp Mode. Is it possible to have Camp Mode on (allowing you to power stuff), without the climate system engaged? Something to test out later today, I guess.

Even if you can't fully disable the climate control (which would be weird), you can set it to Low temp, 1 fan, and turn off AC. Basically this is just setting it to pull fresh air with the lowest fan setting (which I wish there was a simpler way to do), and draws very little power.
 
Any updates on this?

I plan to head out this weekend to go car-camping with a powered cooler/freezer. It has built in “battery protection” which I plan to use in the lowest setting in hopes the the DC-DC Charger will top of the car’s AGM before the cooler shuts off...

GO Series

I will probably use the 12v extension cable it comes with to keep the cooler powered and outside of the vehicle during the day (where I assume it will be more temperate).

I always keep the cabin overheat protection on so based on this thread I hope that’s enough to keep the 12v outlet on continuously. I would guess the cooler uses no more than ~30Wh between the compressor cycling on/off.

I can report that everything went swimmingly. I can't tell exactly what did the trick but the cooler was powered the entire time without any problems. One thing I will mention is the cooler itself obviously puts out heat not a ton but it could be a factor depending on your circumstances.

The Bluetooth app for the cooler indicated that the 12v "battery" was always at 100% with a voltage of ~13.3v; often from distances of over 50ft away and through the car!
 
I can report that everything went swimmingly. I can't tell exactly what did the trick but the cooler was powered the entire time without any problems. One thing I will mention is the cooler itself obviously puts out heat not a ton but it could be a factor depending on your circumstances.

The Bluetooth app for the cooler indicated that the 12v "battery" was always at 100% with a voltage of ~13.3v; often from distances of over 50ft away and through the car!

With the exception of the temp, this voltage and battery level was always the same across all the conditions I had the cooler on: driving, in the car locked up, in the car on Camp Mode, etc.
ICECO GO20 App.jpg
 
I can report that everything went swimmingly. I can't tell exactly what did the trick but the cooler was powered the entire time without any problems. One thing I will mention is the cooler itself obviously puts out heat not a ton but it could be a factor depending on your circumstances.

The Bluetooth app for the cooler indicated that the 12v "battery" was always at 100% with a voltage of ~13.3v; often from distances of over 50ft away and through the car!
Fancy cooler!
 
With the exception of the temp, this voltage and battery level was always the same across all the conditions I had the cooler on: driving, in the car locked up, in the car on Camp Mode, etc.
View attachment 578574
I found this thread and thank you! I just ordered the ICECO GO20 to use in my 2021 Model Y among other things like the beach, I live in Tampa FL. It is comforting to know this will work. Any tips or updates on your experience using the ICECO with your Tesla?
 
Fancy cooler!
Thanks! I found it here:
I found this thread and thank you! I just ordered the ICECO GO20 to use in my 2021 Model Y among other things like the beach, I live in Tampa FL. It is comforting to know this will work. Any tips or updates on your experience using the ICECO with your Tesla?
I will say pin in the 12v plug that you put into the car can be too strong that it pushes the plug out of the socket over time. If that happens, you can unscrew the pin, remove it--with the fuse, and trim the spring down in small sections until you get your desired results. It's good to have the "Car Fridge" App for your phone so you can check that the fridge is still on when you park and walk away or otherwise leave the fridge. And finally, if you'd like you can also easily get a 200 or 500 Watt-Hour portable battery so that you can take it away from the vehicle.

The cooler itself works great, mine came with the zip up cover which is nice to protect it since I take it camping, etc. Also, it's nice having the 12v in the trunk of the MY. Originally I had to snake the plug up to the center console in my M3. It has begun to feel like a necessity to have the cooler in the car for any time of road trip in anything but the coldest months.
 
As a user of a 12V fridge-freezer myself (ARB in my case) I'd like to recommend that folks wire in a proper power connector somewhere. (I use Anderson Powerpole connectors). Using the old "cigarette lighter" standard is sketchy at best... as others have mentioned about it falling out due to spring pressure. Clearly those outlets are not optimized for.... well, anything. But unfortunately a whole industry grew up around that "standard" even though we don't use them for lighting cigarettes. Anyway.... with that out of the way.....

This thread seems to be *mostly* about how and when the 12V outlets stay active. And judging by Istuo-DC's latest posts, I guess the outlets just stay on indefinitely? That's handy. But what I REALLY want to know is how well the car does at clicking on the DC-DC converter and keeping that 12V battery topped up. I'm tapping directly from the batter, so I don't care at all what the outlets in the car are doing. I only care about keeping the 12V battery happy as I draw from it to keep my beer cold.

Does anybody really know how and when and for how long the 12V battery is maintained by the traction pack? It sounds like we've confirmed that it is basically forever. Of course in a car this smart there should be no case where the 12V battery is depleted while there's still energy in the traction pack available to charge it. Because what's in the traction pack won't do you any good if the 12V battery is dead!

So, can anybody confirm that the car opens and closes the contactor appropriately to run the DC-DC to keep the 12V battery charged from the traction pack?
 
  • Like
Reactions: corradoMR2
As a user of a 12V fridge-freezer myself (ARB in my case) I'd like to recommend that folks wire in a proper power connector somewhere. (I use Anderson Powerpole connectors). Using the old "cigarette lighter" standard is sketchy at best... as others have mentioned about it falling out due to spring pressure. Clearly those outlets are not optimized for.... well, anything. But unfortunately a whole industry grew up around that "standard" even though we don't use them for lighting cigarettes. Anyway.... with that out of the way.....

This thread seems to be *mostly* about how and when the 12V outlets stay active. And judging by Istuo-DC's latest posts, I guess the outlets just stay on indefinitely? That's handy. But what I REALLY want to know is how well the car does at clicking on the DC-DC converter and keeping that 12V battery topped up. I'm tapping directly from the batter, so I don't care at all what the outlets in the car are doing. I only care about keeping the 12V battery happy as I draw from it to keep my beer cold.

Does anybody really know how and when and for how long the 12V battery is maintained by the traction pack? It sounds like we've confirmed that it is basically forever. Of course in a car this smart there should be no case where the 12V battery is depleted while there's still energy in the traction pack available to charge it. Because what's in the traction pack won't do you any good if the 12V battery is dead!

So, can anybody confirm that the car opens and closes the contactor appropriately to run the DC-DC to keep the 12V battery charged from the traction pack?

I think it was mentioned earlier that it may not be a good idea to use the 12V battery in the model 3 or Y because it is only provided with about 6A of charging current and the computers will throw an error if you draw too much load from it. Going direct to the DC/DC converter is best for big loads or someone else mentioned there is a 30A circuit you could tap into for the subwoofer.
 
  • Like
Reactions: AlanSubie4Life
I think it was mentioned earlier that it may not be a good idea to use the 12V battery in the model 3 or Y because it is only provided with about 6A of charging current and the computers will throw an error if you draw too much load from it. Going direct to the DC/DC converter is best for big loads or someone else mentioned there is a 30A circuit you could tap into for the subwoofer.
Hmmm. OK. Now poking around for THAT info. I hadn't heard of anybody brave enough to try and "go direct to the DC/DC converter."
 
  • Informative
Reactions: Rocky_H
There’s plenty of discussion of the method here. It does void the warranty on the portions of the vehicle that could be affected by this use, AFAIK:

MASTER THREAD: Powering house or other things with Model 3 12V battery
Thanks for the link Alan.

The one thing I know after years of modifications and research into the Moss Magnuson Warranty Act: There's NOTHING you can do to the car that will legally "void the warranty" if it cannot be proved that what you did broke the thing you're trying to have repaired under warranty. It is up to the warranty provided to show that what you've done has broken the thing you want fixed. Things were a lot different before 1975. Before this act, if you put Recaro seats in your car, and then a month later the car wouldn't start.... the car maker could come back and say: "Yeah sorry. It says right here that if you modify anything, the warranty is void."

So if you tap into the DC-DC converter and the converter blows up, they probably have a case, and the fix is on your dime. On that specific part. But there's no way to "void the warranty" in any sort of umbrella way. Anyway... back to voiding the warranty... :cool:
 
Last edited:
The one thing I know is that there's NOTHING you can do to the car that will legally void the warranty if it cannot be proved that what you did broke the thing you're trying to have repaired under warranty. It is up to the warranty provided to show that what you've done has broken the thing you want fixed.
Exactly. Hence the specific limitations on which portion of the warranty might be voided. In reality if it seems pretty likely that if you overloaded the DC-DC or whatever, and they see clamp marks, etc, or whatever, they’re not going to honor the warranty. Of course it could go to arbitration or whatever.

They have enough diagnostic info and historical info on the vehicles that they might well be able to prove you were using the DC-DC abnormally.

I’m not saying not to do it - users just should be aware and know what they are doing so they don’t damage the vehicle - done properly and carefully, using the car this way would probably be fine.
 
  • Helpful
Reactions: Rocky_H
Thanks! I found it here:

I will say pin in the 12v plug that you put into the car can be too strong that it pushes the plug out of the socket over time. If that happens, you can unscrew the pin, remove it--with the fuse, and trim the spring down in small sections until you get your desired results. It's good to have the "Car Fridge" App for your phone so you can check that the fridge is still on when you park and walk away or otherwise leave the fridge. And finally, if you'd like you can also easily get a 200 or 500 Watt-Hour portable battery so that you can take it away from the vehicle.

The cooler itself works great, mine came with the zip up cover which is nice to protect it since I take it camping, etc. Also, it's nice having the 12v in the trunk of the MY. Originally I had to snake the plug up to the center console in my M3. It has begun to feel like a necessity to have the cooler in the car for any time of road trip in anything but the coldest months.
Will this fit in a model 3.
 
A7C3EA55-F979-4D2F-83E5-771095456EDF.png
I know this topic is old. But related to the original question, I pasted this image of Tesla’s own answer. «When left idle and unplugged, your vehicle periodically uses energy from the Battery for system tests and recharging the low voltage battery when necessary.» So the car always keeps the 12v battery charged.
 
  • Like
Reactions: corradoMR2