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Using Tesla as Power Source During Outage?

Discussion in 'Model 3: Battery & Charging' started by PianoAl, Dec 30, 2019.

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  1. PianoAl

    PianoAl Member

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    We have frequent power outages where we live. With our Leaf, I plug an inverter into the cigarette lighter and leave the car in Drive mode (which allows the traction battery to recharge the 12V battery). I can then use the 110V power to run a lamp or two or the fan on the woodstove.

    Can I do something similar with the Tesla M3?

    Thanks.
     
  2. webbah

    webbah Member

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    The Model 3’s onboard DC to AC converter used to charge the 12v is much weaker than the Model S or X. This is one reason why the 12v socket in the center console is limited to 135 watts or so. If you were to tap in to the 12v system and use a larger inverter the onboard system would not be able to recharge the 12v fast enough before it depletes. As long as you are using less than that you should be ok I would guess.

    You’d likely be better off just getting a Goal Zero 1250 lithium or something similar.
     
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  3. PianoAl

    PianoAl Member

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    Thanks, that would work. Fireplace fan: 20 W; Lamp, 12 W; On-demand water heater electronics, 4 W.

    How should I set things up so the 12V socket will stay powered and the 12V battery will get recharged?
     
  4. webbah

    webbah Member

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    You can put the car in camp mode which should work.
     
  5. eprosenx

    eprosenx Active Member

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    Is this true? I have seen other mentions in the forums about the 12v concerting being able to handle huge current as it is used for power steering and such? (I don’t know if this is true or not)

    There is another thread floating around with someone trying to hook a 3000w inverter to their model 3 directly to the 12v system.
     
  6. webbah

    webbah Member

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    Yes it’s true. I did extensive research on this to prepare for camping season and be able to power all my gear.

    The DC-DC converter in the Tesla M3 is quite limited (12A continuous at 12v is only 144W) and is really only meant to recharge the 12v battery and not a lot else.
     
  7. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    That’s just limited by the fuse for the 12V.

    Remember the DC-DC has to run a bunch of stuff, recharge the 12V battery, etc.

    The direct access point for its output is under the rear seat. It probably has a couple thousand watts output capacity, though I do not know the exact specs. Actually keeping it awake is another matter. You apparently can’t tap off the 12V battery without discharging the 12V, because it is limited to something like 5A charging rate, and the car will eventually flag it as a defective 12V battery, because that tap off of the DC-DC converter is not behaving as expected.

    It seems like camping mode will be a convenient way to keep the car awake - previously I am not sure how easy that would have been (even when leaving a door open I do not know how the behavior is defined...).

    As mentioned, there is another thread around here discussing the options for using the car as a backup power source. Should not be hard to look up - been discussed within the last couple weeks.
     
  8. jjrandorin

    jjrandorin Moderator, Model 3, Tesla Energy Forums

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    • Helpful x 1
  9. webbah

    webbah Member

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    DC-DC converters are expensive and the M3 has a smaller one than Model S or X. Obviously there is no alternator in an EV. If Tesla used a larger DC-DC converter it would increase the cost of the car for very limited use cases like this. Anyway, sure you can pull more from the 12V battery directly, but the onboard DC-DC converter won’t keep up to top it off. It also only kicks in when the 12V battery hits 50% or so.
     
  10. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    Reread my post - this is exactly what I said. That is why you need to tap off the DC-DC output directly if you want to use its maximum output capability (whatever that may be). Whether this is actually a good idea, I do not know.

    For the OP his power requirements are low enough that he can use the 12V plug. He just has to keep the car awake. Maybe camp mode will work. Presumably this means he’ll be using 500W or so from the car all the time due to the ~250W overhead.
     
  11. Pezmc

    Pezmc Nomad

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    Did you find a trick to keep the car (and therefore the DC/DC and the high voltage battery relay) awake?
     
  12. Gasaraki

    Gasaraki Active Member

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    CAMP MODE
     
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  13. Transformer

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    The Leaf supports CHAdeMO vehicle to home (V2H) power using a bidirectional charger, which should finally be coming to the US.
    Nissan Leaf as home energy device: Wallbox will soon enable it in the U.S.

    There are rumors that the Model 3 has the hardware to do this. If so, we'd still need a supporting bidirectional charger.
     
  14. Gasaraki

    Gasaraki Active Member

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    There was a rumor but then it was debunked. Don't know what true anymore, however it would be amazing if the Model 3 really did have the hardware already.
     
  15. Tomc62

    Tomc62 Member

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    If you have such frequent outages why not install a whole house generator that runs on natural gas or propane? Protect your Tesla. You might need it during an outage.
     
  16. jjrandorin

    jjrandorin Moderator, Model 3, Tesla Energy Forums

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