Whole home UPS

JoshKJoshK Solar Expert Posts: 232 ✭✭
As I've mentioned I reserved a Powerwall and after filling out their survey it's possible I will be talking to an installer some day soon.  I want to drill him good on meeting my needs for a good price, and maybe some members here can help with that.

My goal is to use their backup model to achieve a whole home UPS.  (Uninterrupted Power Supply).  Short power outages averaging 30 seconds are very common here, some lasting 5 minutes.  And an annual outage of about an hour.  How common are our outages?  Monthly or more.  The last one was less than 24 hours ago.  It's bad for electronics and has already cost us a dishwasher.  And then there's the 3D printer that ruined 8 hours of printing yesterday when the power went out.
I want to avoid littering my house with individual UPS boxes.

I know the 'uninterrupted' is going to be a tall order, as most backup systems require you to throw a switch.  I am not interested in that.  Has a member here installed such a system using lead batteries?  And how did that work out?


  • BB.BB. Super Moderators, Administrators Posts: 29,482 admin
    You can get a standard Inverter-Charger (Outback, Xantrex/Schneider, Magnum, etc.) that will switch from AC mains to AC backup power... Not sure what their transfer times are--But I would not expect it to be better than 1/2 switching (~16 msecond)--Which is the "standard" UPS switching spec.

    Or you can go with a standard UPS dedicated to just the equipment you want to backup. 16 msec fail over time is standard. However, in my lab testing (with test gear that randomly throws AC faults) while the computers always survived the fail overs. In real life, I would get about 10% of the power losses where the computers would reboot (I could never reproduce these failures).

    So that goes to continuous conversion UPS... AC mains => battery charger => battery => AC inverter => loads. You may choose this type of UPS for your 3D printer + driver computer. This is the "ideal" from a reliability point of view--But is probably the least efficient.

    There is also the down side... The more hardware you throw into the mix, the more points of failure there are...

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Solar Expert Posts: 8,368 ✭✭✭✭✭
    Going to a whole house UPS, you have to either
    Decide on only a few circuits to back up (3-D, computer, kegerator, furnace, sump pump)
    Backup the whole service feed, and hope no one fires up the toaster AND the blowdryer at the same time.

    Be sure the UPS can power the circuits you decide on.  It's going to likely need another breaker panel for the UPS loads.
    Don't be surprised at the costs
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  • JoshKJoshK Solar Expert Posts: 232 ✭✭
    I have checked my loads, and one powerwall should do the trick.  The only two loads that could become a problem is if the A/C is running along with the oven.  I might hold, it might kick out.   I sure don't want all my power going through the inverter on a normal day.  And if I need another panel, that's off the table for this house.
  • ImurphyImurphy Registered Users Posts: 16 ✭✭
    Josh Its been a while, did you get a power wall?
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