EV battery for House Backup power

Discussion in 'General' started by papab, Jan 16, 2021.

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  1. papab

    papab Member

    How to use the EV battery for house backup power? Seems like it should be done. Most new EV's could power my house for several days. If I get my grid tied PV set up to charge the EV, even more time than that. Has anyone here set that up, or looked into it. What EV charging connections are compatible? I read somewhere that CCS could do it, but not yet.
    I'm just starting to look into this. So far I've found this: https://dcbel.ossiaco.com/
     
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  3. Recoil45

    Recoil45 Active Member

    Go to the outback power forum to do some reading. They were doing grid tie systems with battery backup for years before tesla power-wall was ever a thing. If you are not heating or cooling with electricity your claim of several days off an EV battery might play out. If you are heating or cooling you may want to dial that back to something in the scope of hours.


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  4. papab

    papab Member

    I'll check out the outback forum, but my question is not about basic battery backup, but how to tie into the EV.
    With heat pump, this time of year, I use about 20kwh/day. If the grid was down I could back off the heat, cooking, and hot water & dial that way back.
     
  5. Other than Tesla which apparently has the capable hardware (not yet software enabled):
    https://thenextweb.com/shift/2020/05/20/engineer-finds-tesla-model-3-is-secretly-equipped-with-hardware-for-powering-homes/
    with mention late in the article of VW plans for future EVs.
    The only other one has an "3.5 kW on board inverter" equipped and scheduled for late 2021 would be Hyundai Ionic 5. Obviously some work would have to be done for interconnection to tie in to your system. I am waiting to see what kind of sine wave is produced among duty rating etc.
    Do you presently own an EV, and if so - what type?
     
  6. papab

    papab Member

    I don't have one yet, looking at a Y, id4, or xc40 sometime in the near future. If any of those had the capabilites to connect an output, that would be a big plus for me.
     
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  8. papab

    papab Member

    It looks like that Tesla feature has been 'debunked'.
    I see articles on vehicle to grid, with the car providing AC grid synced power. I think for a backup home power setup, DC output to an inverter might make more sense.
    I found this:
    https://atlanticces.com/delta-v2hv2g-bidirectional-charger/
     
  9. gooki

    gooki Active Member

    DC output to an inverter is how Chademo (nissan leaf) does v2h / v2g.

    The problem is the v2h inverters were $10,000. I've no idea why they aren't on par with solar inverters at $1,000.
     
  10. SouthernDude

    SouthernDude Active Member

    Using the EV battery as a home energy source is an overrated concept. This is something that only a tiny number of hobbyists will do.

    If the majority of people are going to be charging their car home overnight, then why would it make sense to deplete the battery? It doesn't. Even if they have grid-tied PV on their roofs, that doesn't automatically mean that the homeowner has their car plugged in somewhere else during the day to charge.

    I don't know why people give credit to this idea when it is obvious that it is a hobbyist thing.
     
  11. gooki

    gooki Active Member

    It's more about peak shaving, and emergency backup than it is about powering the house all night.

    My electricity is 2x more expensive between 5pm and 9pm when my EV is sitting in the garage doing nothing.
     
    electriceddy likes this.
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  13. SouthernDude

    SouthernDude Active Member

    Sure, I can see how that may be cost effective in some markets, but I doubt very many people would still want to participate. Seems like the pay off period would be pretty steep though.
     
  14. Recoil45

    Recoil45 Active Member

    And do the savings outweigh the battery longevity hit your battery will take from additional cycles? I doubt it, but time will tell.


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  15. papab

    papab Member

    I don't think I would use my EV battery for peak shaving, or daily use, but occasional emergency power would sure be nice.
     
    bwilson4web likes this.

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