It's easy to check with a volt meter. If it's more than 13V, it's being charged from the traction battery. It should be a steady voltage, not fluctuating like it was charging and discharging in cycles. I guess on a MX you can't leave a door ajar because of the auto-closing, but on a Model 3 you could just turn off the climate control and leave a door latched but ajar and the car will stay on.
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Sunshine State
Automotive Enthusiast
Tesla service runs inverters off the 12v battery to power theIr small compressors and other accessories in the back of their Model S service cars. I asked about it and if I remember right they keep the cars on while using them.
If you wire your inverter directly to your 12 volt battery, you do not have to keep the car "on".
Lectric_Agent
2019 MXPL+ Raven
mspohr
Well-Known Member
polymathic
Member
The inverter is for 1200W continuous, so it can take a bit more when something kicks on. Fridge and freezer work together fine, and draw 400W to 600W. To turn on furnace, I first disconnect the fridge & freezer. Once house is warm, I turn off furnace and reconnect freezer & fridge. At all times with fridge and freezer running there is at least 600W available for lights, TVs, etc.
FlatSix911
Porsche 918 Hybrid
FlatSix911
Porsche 918 Hybrid
Here is another example with a small inverter... EVs are not a problem during California fire season, they’re the friggin’ solution - Electrek
Electric-car naysayers jump to the conclusion that California EV drivers were stranded during recent power outages. But Carleen Cullen, executive director of Cool the Earth, used juice from her two EVs to keep critical appliances running during fire season. PG&E shut off power in regions throughout Northern California to mitigate the risk of wildfires, a threat that has dramatically increased in recent years. The solution for Cullen was to buy a $25 inverter from Amazon.
When her Marin County home’s power was shut off, she plugged the simple device into her Chevy Bolt’s cigarette lighter and ran an extension cord to power a radio, computer, cell phone, and lights. “It was an excellent solution,” she said. “And I did the same thing with my Tesla Model 3 to get lights running in my kitchen and TV room.”
Cullen said that both EVs performed comparably as back-up generators. A day of power back-up used about six miles of driving range in the vehicles. Cullen added that she knows fellow EV drivers who during the outages used a more robust solution accessing the cars’ 12-volt battery to power refrigerators. Alarming reports about EV drivers getting stranded with empty batteries overlook the easy solution of fully charging the car before an outage. “I recommend that everybody plug in every night during fire season,” said Cullen. “Just always keep the car full. It’s so easy.”
Electric-car naysayers jump to the conclusion that California EV drivers were stranded during recent power outages. But Carleen Cullen, executive director of Cool the Earth, used juice from her two EVs to keep critical appliances running during fire season. PG&E shut off power in regions throughout Northern California to mitigate the risk of wildfires, a threat that has dramatically increased in recent years. The solution for Cullen was to buy a $25 inverter from Amazon.
When her Marin County home’s power was shut off, she plugged the simple device into her Chevy Bolt’s cigarette lighter and ran an extension cord to power a radio, computer, cell phone, and lights. “It was an excellent solution,” she said. “And I did the same thing with my Tesla Model 3 to get lights running in my kitchen and TV room.”
Cullen said that both EVs performed comparably as back-up generators. A day of power back-up used about six miles of driving range in the vehicles. Cullen added that she knows fellow EV drivers who during the outages used a more robust solution accessing the cars’ 12-volt battery to power refrigerators. Alarming reports about EV drivers getting stranded with empty batteries overlook the easy solution of fully charging the car before an outage. “I recommend that everybody plug in every night during fire season,” said Cullen. “Just always keep the car full. It’s so easy.”
OBX John
Autonomous Driving Enthusiast
Rather than buy a generator, I'd much rather give the money to Tesla to enable a "stationary power source" feature.
Come on Tesla, put an outlet in the car and TAKE OUR MONEY!
Come on Tesla, put an outlet in the car and TAKE OUR MONEY!
Does anyone know how to access the 12V battery terminal on a recent model S without the black nose come?
FlatSix911
Porsche 918 Hybrid
Check your owners manual for the location... you will have to go directly to the 12V battery.
Does anyone know what this fuse is for or it's value? It's integral to the positive post terminal on a 2019 MS. I want to connect a 1500 watt inverter, but don't want to blow the fuse. Of course I can connect the inverter to either side, presumably to the car side since the battery charger will ultimately be powering the inverter, but i'm concerned about blowing the fuse at initial start-up of the inverter load when it will draw on the battery until the car charger recognizes it's time to "charge".
Attachments
mspohr
Well-Known Member
Cape Coddess
2 Roths full - holding!
This is exactly what I was planning on doing! Thank you so much!
Would you mind sharing a photo of your inverter connected to your 12 volt please?
Attachments
Last edited:
The thinner yellow wire with clamp is attached by ring terminal at one of the four bolts that bolt the inverter in place inside the microwave box that have black sealer applied to the outside. The other clamp end goes to chassis ground.
The red (hot 0 gauge) attaches to the battery at the location shown (red shrink) without the need to unbolt the car hot lead from the circuit breaker block located at the top of the 12 volt battery and is in the picture at lower left. The bolt is long enough to place the hot ring terminal on the bolt and add a top nut without having to unbolt the existing hot cable underneath.
The black 0 gauge attaches as shown in the far right of the picture to the 12 volt negative attachment. Again no need to remove the negative clamp on the terminal but you can combine it as shown.
I put a heavy gauge Andersen connector between the battery and the tub for ease of assembly and disassembly. I have provided pictures of the measurements of the two harness wires to be made. One side of the harness attaches to the 12 volt battery and attaches to the other half that feeds through the tub. the inner tub side connects to a resettable circuit breaker on the positive side and then continues to the converter.
The negative gets another detachable Andersen before continuing to the inverter.
Take note of the modification of the tub liner at the pass through holes for the harness and the wiring protection and grommets.
I'm having trouble with the internet and pictures so sorry if it is disorganized. It is not taking all of my pictures etc... I had a picture of the supplies to do this project but can't find it. I know one of the pictures shows a 250 amp re-settable breaker but you should use something smaller like a 200 amp to make sure that it trips before the high amp (I believe is 235 amp) fuse between the HV and the 12 volt battery.
This installation uses a 2000 watt inverter that has internal fuses as well.
The red (hot 0 gauge) attaches to the battery at the location shown (red shrink) without the need to unbolt the car hot lead from the circuit breaker block located at the top of the 12 volt battery and is in the picture at lower left. The bolt is long enough to place the hot ring terminal on the bolt and add a top nut without having to unbolt the existing hot cable underneath.
The black 0 gauge attaches as shown in the far right of the picture to the 12 volt negative attachment. Again no need to remove the negative clamp on the terminal but you can combine it as shown.
I put a heavy gauge Andersen connector between the battery and the tub for ease of assembly and disassembly. I have provided pictures of the measurements of the two harness wires to be made. One side of the harness attaches to the 12 volt battery and attaches to the other half that feeds through the tub. the inner tub side connects to a resettable circuit breaker on the positive side and then continues to the converter.
The negative gets another detachable Andersen before continuing to the inverter.
Take note of the modification of the tub liner at the pass through holes for the harness and the wiring protection and grommets.
I'm having trouble with the internet and pictures so sorry if it is disorganized. It is not taking all of my pictures etc... I had a picture of the supplies to do this project but can't find it. I know one of the pictures shows a 250 amp re-settable breaker but you should use something smaller like a 200 amp to make sure that it trips before the high amp (I believe is 235 amp) fuse between the HV and the 12 volt battery.
This installation uses a 2000 watt inverter that has internal fuses as well.
Attachments
Last edited:
Sunshine State
Automotive Enthusiast
The Tesla Service Tech I spoke to said even though they wire direct to the 12v that you should keep the car on while using the inverter. He said they have had issues when the don’t.
Nope, he gave you incorrect or misinformation when it is wired direct. Especially with a lithium 12 volt. Think of when you are sitting in you car Supercharging for example. You could be using many different 12 volt system services while in your car charging etc.
The HV system will constantly maintain your 12 volt as needed. Now a lead acid 12 volt is inferior to using a lithium and has a shorter lifespan in comparison in any regard using inverter or not. Your HV battery will cool as necessary regardless of any scenario as well as maintain voltage to your 12 volt.
Last edited:
Sunshine State
Automotive Enthusiast
The service cars don’t run lithium 12v battery’s, at least the Tech I spoke with said they don’t. Im not debating anything, just passing along what the Tesla service tech said in regards to this. I don’t have an inverter in any of our Teslas so this is only what he told me. I honestly have no interest in running anything off my car.
Similar threads
- Question
