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Connecting my mains inverter to HV battery

Discussion in 'Gen 3 Prius Technical Discussion' started by PhilPaw, Jul 30, 2021.

  1. PhilPaw

    PhilPaw Junior Member

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    Hi all,

    I have built a homemade 200V DC inverter to power my house during blackouts, and want to connect to my Gen 3 Prius to use it as a generator. Much like the PlugoutPower commercial system.

    It's a long shot, but I'm specifically interested in talking with anyone that has done this before.

    I'd like to know how many watts I can pull from the Prius before it throws an error code and shuts down.

    Also any info on what code is thrown, and whether Techstream can reset it.
     
    #1 PhilPaw, Jul 30, 2021
  2. bisco

    bisco cookie crumbler

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    no info in all those threads?
     
    #2 bisco, Jul 31, 2021
  3. ChapmanF

    ChapmanF Senior Member

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    Because it's more of an aftermarket mod, there isn't a lot published by the manufacturer that's directly on point.

    Maybe one of the best resources you'll find will be the supported vehicle list over at PlugOut Power, which lists a bunch of hybrid and PHEV models and whether PlugOut's 3kW or 5kW kit is recommended for each.

    Your first reaction may be that those numbers are very comfortably under the power levels that you know the system handles in normal driving, which are in the ballpark of ten times that.

    But then you realize that some other considerations are in play. A lot of the time when you're using your mains inverter, the car is likely to be stationary. One limit on the practical power may be how much cooling is available when the car is stationary and relying only on the radiator fans.

    Another may be that the engine is generally turning at idle speed. We already know it isn't literally idling when it charges the battery in park; I've certainly seen mine deliver charge currents up to 20 amps (more than 4 kW), and you can hear the engine note deepen as it throttles up to do that, but it is still around idle RPM.

    There may be nothing programmed in to the power management control ECU for requesting higher engine revs while stationary, if it notices you are drawing more power than the engine can produce at 1200 rpm or so. In the unmodified car, there wouldn't be any need for doing that.

    So it seems that the limits Randy recommends for his commercial solutions have been pretty much the same ballpark everyone has been playing in.
     
    #3 ChapmanF, Jul 31, 2021
  4. PhilPaw

    PhilPaw Junior Member

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    Here is Richard from PriUPS answer.
    He has had experience with UPS rated in the 10kva range but only on the Gen 2.
    He had problems with voltage droop tripping his inverter over 3kw, but never a vehicle based over-current error. So I might try a 5 or 6 kW resistive load and see what happens!


    Howdy!

    Short answer: I don’t know.

    Somewhat longer: I did this project with a Gen 2 model year 2005. I was going to replicate it with a Gen 3 plug-in but traded it in for a Tesla after deciding it wasn’t worth the effort for other reasons having to do with my solar inverters. I have never seen any fault conditions caused by overcurrent. After I decided that the average load shouldn’t exceed 3kW, I’m sure the peak load never exceeded the 25 or so kW of which the battery was capable, and so never had errors, blown fuses, or any other issues.

    Good luck with your project!

    Regards,
    Richard
     
    #4 PhilPaw, Jul 31, 2021
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