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12v On Board DC/DC Charger

Hi all, I've searched the forums and haven't been able to find any answer to how much power the DC/DC converter is able to supply the 12v in watts. I know the cigarette sockets in a M.Y. can run 15A at 12v -- but my main concern is the load being too much for the 12v and discharging it to a brick overtime, such as on a long roadtrip or while camping.

Basically -- if I run 100-150watts off one cigarette lighter, will the onboard charger be able to keep the 12v from being dead? Does anyone know the approx. power the DC/DC can supply the 12v? I'm curious if both cigarette lighter plugs (totaling ~300watts) would out pace the converter.

Thanks for responding!
 
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brkaus

Well-Known Member
Jul 8, 2014
8,180
6,729
Austin, TX
Probably similar to the 3?

 
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jcanoe

Active Member
Oct 2, 2020
3,873
3,957
Maryland
I believe the Tesla Model Y's DC-to-DC converter's maximum output is right around 2kW. The 12V accessory outlet(s) are limited to 12A continuous, 16A peak. The manual does not state if this limit is for each 12V outlet for for both 12V outlets combined. There is no fuse; if the Tesla Model Y detects an overload the Tesla vehicle's smart circuit breaker will shut off power to the 12V accessory circuit for a period of time. (Reference: Tesla Model Y Owner's Manual page 21.)

https://www.tesla.com/sites/default/files/model_y_owners_manual_north_america_en.pdf

The 12V battery in the Tesla Model Y is rated for 40Ah. You don't have to be concerned with running down the 12V as the Tesla Model Y will charge the 12V battery as required using power from the high voltage battery. If you use Camp mode then the 12V accessory ports, USB ports remain powered on. When in Camp mode you can turn off the climate control system to conserve power.
 
Last edited:
I believe the Tesla Model Y's DC-to-DC converter's maximum output is right around 2kW. The 12V accessory outlet(s) are limited to 12A continuous, 16A peak. The manual does not state if this limit is for each 12V outlet for for both 12V outlets combined. There is no fuse; if the Tesla Model Y detects an overload the Tesla vehicle's smart circuit breaker will shut off power to the 12V accessory circuit for a period of time. (Reference: Tesla Model Y Owner's Manual page 21.)

https://www.tesla.com/sites/default/files/model_y_owners_manual_north_america_en.pdf

The 12V battery in the Tesla Model Y is rated for 40Ah. You don't have to be concerned with running down the 12V as the Tesla Model Y will charge the 12V battery as required using power from the high voltage battery. If you use Camp mode then the 12V accessory ports, USB ports remain powered on. When in Camp mode you can turn off the climate control system to conserve power.
Thank you! Cased closed!
 
I believe the Tesla Model Y's DC-to-DC converter's maximum output is right around 2kW. The 12V accessory outlet(s) are limited to 12A continuous, 16A peak. The manual does not state if this limit is for each 12V outlet for for both 12V outlets combined. There is no fuse; if the Tesla Model Y detects an overload the Tesla vehicle's smart circuit breaker will shut off power to the 12V accessory circuit for a period of time. (Reference: Tesla Model Y Owner's Manual page 21.)

https://www.tesla.com/sites/default/files/model_y_owners_manual_north_america_en.pdf

The 12V battery in the Tesla Model Y is rated for 40Ah. You don't have to be concerned with running down the 12V as the Tesla Model Y will charge the 12V battery as required using power from the high voltage battery. If you use Camp mode then the 12V accessory ports, USB ports remain powered on. When in Camp mode you can turn off the climate control system to conserve power.
For "Model Y will charge the 12V battery as required using power from the high voltage battery.", will it do that even when the car is "off"? (not sure of all the modes the car can be in, they keep postponing my delivery date!)
I'm thinking if I run a mini fridge (48w) from the 12v outlet in the trunk (which is always on I assume), I can basically run it forever (given how large the main battery is when compared to this load)? Say if I leave the car and the fridge and go for a multi-day hikes..
 

jcanoe

Active Member
Oct 2, 2020
3,873
3,957
Maryland
For "Model Y will charge the 12V battery as required using power from the high voltage battery.", will it do that even when the car is "off"? (not sure of all the modes the car can be in, they keep postponing my delivery date!)
I'm thinking if I run a mini fridge (48w) from the 12v outlet in the trunk (which is always on I assume), I can basically run it forever (given how large the main battery is when compared to this load)? Say if I leave the car and the fridge and go for a multi-day hikes..
The Model Y will maintain the 12V battery as required even if the Model Y enters sleep mode. When the Model Y is powered on; in Camp mode or Dog Mode then the 12V accessory outlets and the USB ports remain powered. When the Model Y enters sleep mode the 12V accessory outlets and the USB ports are not powered.

You can run the mini fridge from the 12V accessory port but not using the 12V battery for the power source. The 12V battery is not designed for heavy electrical loads. The Tesla Model Y only draws ~25W when the Model Y is in sleep mode. (The 12V battery is rated for 40 or 45Ah.) For the 12V accessory port to remain powered on the Tesla must be powered on. The power drain when powered on, even with the climate control turned off is ~230W.

There are some portable battery power units with solar panels. One of those should be able to power the mini-fridge.

I don't camp but wouldn't the scent of food stored in a vehicle with no humans around invite all sorts of critters to the vehicle, including bears?
 
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Reactions: Acps110
Interesting. Even my old CX-5 has the accessory port in the trunk always on.

I guess even ~230W+48W drain is not that bad, for 2 days it would be ~13.3 kwh, or ~18% of the Model Y LR battery. But yea it will be wasteful.

I imagine the car to be sealed pretty well (better than the trashcan in the campsite), so bear shouldn't be a problem. Birds will probably poop all over it. They like shining cars
 

jcanoe

Active Member
Oct 2, 2020
3,873
3,957
Maryland
You could run a test, at home, to see how much of the Tesla battery (the main battery) is used over 24 hours. Turn off Sentry Mode, Summon Mode (if equipped with FSD.) Turn off Cabin Overheat Protection (only active for 12 hours after you park but Cabin Overheat Protection can use an average of ~750Wh/hr in my experience while active.)

Camp Mode does not automatically lock the vehicle when you exit. I believe you would have to use the Tesla app to lock the vehicle. Of course you would want to turn off the HVAC before exiting.

This additional load on the 12V battery will require the battery be charged by the Tesla vehicle more frequently. When in Sleep Mode, consumption is normally 25W, you are basically tripling this load. If the 12V battery can normally maintain the Tesla's essential 12V systems for 24 hours between being charged then this would happen every ~8 hours. Doing this occasionally, when camping, would not matter. Long term this would shorten the life of the 12V battery (the 12V battery in the Tesla Model Y will typically last around 2 years, maybe 3 years.)
 

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