Is it safe to connect a large inverter to the 12V battery?

[jrickard]

The Tesla Model S DC-DC converter is rated at 2500 watts. That's a little over 200 amps. I see know reason you couldn't do 2000watt inverter with 3000 watt surge off the 12v battery. You would need to connect it directly to the 12v battery terminals of course.

 

[zwede]

I would put the car in "camper mode" so the contactors stay closed and DC-DC stays active. If not in camper mode you will drain the 12V battery really fast, contactors close and charge it back up, contactors open, and this cycle repeats over and over. It would wear out your 12V and contactors quickly.

But in camper mode I don't see a problem.

 

[David99]

I would put the car in "camper mode" so the contactors stay closed and DC-DC stays active. If not in camper mode you will drain the 12V battery really fast, contactors close and charge it back up, contactors open, and this cycle repeats over and over. It would wear out your 12V and contactors quickly.

But in camper mode I don't see a problem.

That's an interesting point. I wonder if the car would sense such a high load on the 12 Volt system and just keep the DC-DC converter working thus never disconnecting the main battery or opening/closing the contactor. I will experiment soon.

 

[W0QR]

Along the same line, I have one of those little refrigerators (Peltier). Has anyone tried running one of these off the 12 volt acc socket. Is the 12 volt socket active all the time?

 

[tga]

Along the same line, I have one of those little refrigerators (Peltier). Has anyone tried running one of these off the 12 volt acc socket. Is the 12 volt socket active all the time?

The socket shuts off when the car turns off. Some have pulled the relay and installed a jumper to make it live all the time - there are posts here (somewhere).

Personally, I hate lighters that shut off when the car is off. If I want to leave my phone in the car charging, that's my business. I don't need to be protected from myself, thank you very much.

 

[FlatSix911]

The socket shuts off when the car turns off.
Some have pulled the relay and installed a jumper to make it live all the time - there are posts here (somewhere).

Personally, I hate lighters that shut off when the car is off.
If I want to leave my phone in the car charging, that's my business. I don't need to be protected from myself, thank you very much.

Here is the relay/jumper hack to keep the 12V outlet live all he time

Ingineer said: ↑
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 owner’s 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.

 

[bemental]

And older post, but I’d thought I’d add this product in case OP is still looking for a portable solution to his UPS woes.

Goal Zero Yeti 1000 Lithium Portable Power Station | | Goal Zero

Managed to grab one of these open box from the manufacture’s website for about 50% off. Still isn’t cheap, but the funcationality it provides is pretty spectacular.

I’ve got all sorts of ideas brewing in my mind now about traveling with our Tesla and this little guy.

 

[TaoJones]

And older post, but I’d thought I’d add this product in case OP is still looking for a portable solution to his UPS woes.

Goal Zero Yeti 1000 Lithium Portable Power Station | | Goal Zero

Managed to grab one of these open box from the manufacture’s website for about 50% off. Still isn’t cheap, but the funcationality it provides is pretty spectacular.

I’ve got all sorts of ideas brewing in my mind now about traveling with our Tesla and this little guy.

Curious to hear what you and others who follow this path end up powering via an inverter.

I was originally going to power a Nespresso that I had with an inverter. Then I found out that due to the surge amperage requirements, I would need a 4kW sine wave inverter which at the time was the size of a healthy shoebox and would require some fairly stout cabling on top of that. Neither of which was given anything that resembled a blessing by Tesla.

That led to having a 12V cable run from the fuse box aft under the starboard front seat with 2x12V receptacles. From there, a fridge/freezer and any other DC-powered device du jour are powerable 24/7. The DC espresso maker runs fine from the onboard 12V; it will produce 2 double shots in less than 10 minutes and the frother for milk for a proper cappuccino is manual.

So here’s the thing. I’ve got a DC cable to charge my laptop, and the same for a portable printer. There exist DC microwaves, crock pots and popcorn makers, but I keep forgetting to invest in any of those and on top of that the ones I do find cry out for immediate re-wiring out of concern for personal safety because robust... they are not.

So... a 1kW inverter opens up some possibilities but I’m drawing a blank. I tend to eat salads and granola on the road (hence the fridge) but could be persuaded to stow an Instant Pot (if it would run; I have my doubts and will research) as then I could live large in a pinch with some Roadkill Stew. Would probably beat chilled Varmint Tartare, which would be the best I could do now.

What?! Reduce, reuse, recycle! In 5 years when an RV can be built on top of a Tesla utility truck bed/platform, this will be a non-issue except for how to install a proper hot tub. A Tesla Semi and 53’ converted trailer would solve that, but I digress, and besides, a friend has been extolling the virtues of a small yet complete RV that fits into a single parking space. Choices, choices.

 

[FlatSix911]

Just purchased a 12V inverter with a digital display to monitor input/output voltage and amps... review to follow
https://www.amazon.com/gp/product/B01FEUD9OO/ref=ox_sc_act_title_6?smid=A2YZ44EQE6CQC7&th=1

 

[TaoJones]

Just purchased a 12V inverter with a digital display to monitor input/output voltage and amps... review to follow
https://www.amazon.com/gp/product/B01FEUD9OO/ref=ox_sc_act_title_6?smid=A2YZ44EQE6CQC7&th=1

Looks like fun.

Curious to hear whether you encounter any impact from the following cautionary product note, and in particular from the last sentence.

Note:
Never run the inverter with any loads higher than 150W via the cigarette lighter outlet in your vehicles since the maximum allowed current through cigarette lighter outlet is 15A. Please use the battery clamp cable with connection directly to the 12V battery while you run any loads higher 150W but lower than 750W.

 

[Shock-On-T]

I’m a bit north of Orlando and getting ready for Irma. Last year after hurricane Matthew I was without power for three days. I have a large saltwater fish tank that can go for a few hours without power if necessary, but the less time without power the better. I have a large portable generator to power the house and the fish tank if (when) the power fails, but it occurred to me today that if the power goes out toward the beginning of the storm I could have a long wait before it’s safe to put the generator outside and I could potentially still be without power for some time. Luckily with Matthew my power failed at the very end of the storm.

I happen to have a 700 watt 12V to 120V inverter that I was considering connecting to my Model S and using it to power the fish tank and maybe a light or two in the event that the power fails before I can safely use the generator. Luckily I have a 2015 Model S with the 12V posts behind the nose cone, so it would be pretty easy to pull the nose cone and connect the inverter and run an extension cord though the garage door into the house.

However that inverter can draw a decent amount of power (the fish tank pumps and such probably draw about 200 watts to 250 watts as they run). I know that the car will top off the 12V battery as it drains even as the car is off, but how quickly will it do so? I’m afraid that I may be drawing more power than it can provide to top off the battery and eventually I’ll wind up with a dead 12V battery. Alternately I could start the car and leave the door open a bit so hopefully it would stay on which may provide more power to the 12V system.

Has anyone tried anything like this? Do you know if the car will be able to keep up with my power draw for hours?

250W would be less than the car draws from the 12V battery in some scenarios (headlights on, subwoofer pumping and phone charging) so I would guess it’s safe enough.

 

[n2mb_racing]

Looks like fun.

Curious to hear whether you encounter any impact from the following cautionary product note, and in particular from the last sentence.

Note:
Never run the inverter with any loads higher than 150W via the cigarette lighter outlet in your vehicles since the maximum allowed current through cigarette lighter outlet is 15A. Please use the battery clamp cable with connection directly to the 12V battery while you run any loads higher 150W but lower than 750W.

The point of the last sentence is that the power outlet is fused at 15a, so higher than 150w is not possible without going direct to the battery or another high current tap point.

 

[zap fizzle]

Yes please keep us updated about how this goes. I could run all the vital stuff in my house off the dc-dc converter in a Nissan Leaf via a 1kW inverter and would love to know how possible this is on Tesla.

 

[tga]

Yes please keep us updated about how this goes. I could run all the vital stuff in my house off the dc-dc converter in a Nissan Leaf via a 1kW inverter and would love to know how possible this is on Tesla.

No way you could pull 1kW continuous off the Leaf's 12V system. There's no way the DC-DC converter in the Leaf can provide that much power. That's a huge, expensive converter, and completely unnecessary.

 

[zap fizzle]

No way you could pull 1kW continuous off the Leaf's 12V system. There's no way the DC-DC converter in the Leaf can provide that much power. That's a huge, expensive converter, and completely unnecessary.

It's good for quite a lot more than that; it does about 130A.

 

[miimura]

No way you could pull 1kW continuous off the Leaf's 12V system. There's no way the DC-DC converter in the Leaf can provide that much power. That's a huge, expensive converter, and completely unnecessary.

All modern EVs can support 1kW from the 12V system as long as the car is completely on and ready to drive. Of course, you also have to have appropriately thick cables connected directly to the 12V battery.

 

[tga]

Nevermind, I'm an idiot. I had it in my head the Tesla DC-DC was good for 250 watts. I was off by an order of magnitude, per Jack's post on the prior page. I'll blame the 3 hours of sleep last night...

The Tesla Model S DC-DC converter is rated at 2500 watts. That's a little over 200 amps. I see know reason you couldn't do 2000watt inverter with 3000 watt surge off the 12v battery. You would need to connect it directly to the 12v battery terminals of course.

I'm searching TMC for specs on the converter, and Jack's post comes up. I didn't even see it was right in front of my face. *sigh*

 

[FlatSix911]

Looks like fun.
Curious to hear whether you encounter any impact from the following cautionary product note, and in particular from the last sentence.

Note:
Never run the inverter with any loads higher than 150W via the cigarette lighter outlet in your vehicles since the maximum allowed current through cigarette lighter outlet is 15A. Please use the battery clamp cable with connection directly to the 12V battery while you run any loads higher 150W but lower than 750W.

I did a bit of research and found that I could safely pull 750 watts from the 12V battery using the front terminals behind the nose cone
Not planning to use the 150-watt convenience outlet inside car unless I have a small load.

 

[n2mb_racing]

I did a bit of research and found that I could safely pull 750 watts from the 12V battery using the front terminals behind the nose cone
Not planning to use the 150-watt convenience outlet inside car unless I have a small load.

Did you find if those posts are fused? Was also thinking of hooking up there, in an emergency. Was hoping they would support 200a

 

[FlatSix911]

Did you find if those posts are fused? Was also thinking of hooking up there, in an emergency. Was hoping they would support 200a

Yes, the remote charging terminals are protected with a 50A fuse ... you need to go directly to the battery if you want more
I chose the convenience of accessing the nose cone charging posts vs. some disassembly of the frunk to access the 12V directly.