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Inverter to Manual Transfer Switch

Discussion in 'Gen III 2010+ Prius Accessories and Modifications' started by Frank Perkins, Jun 16, 2013.

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  1. Frank Perkins

    Frank Perkins Member

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    I have seen a ton of threads about using your Prius as a generator for the house. However, I haven't found any threads about plugging the inverter into a manual transfer switch.

    What I have installed now is Reliance 30 Amp transfer switch which has an outlet on the outside of the house to connect the NEMA L14-20 generator cable.

    I got the 10 switch not because I wanted to run everything, but I wanted to choose what I wanted running. For example, I found out that my "Core" items of fridge, internet and lights is only 400w (1000w) peak. I'm thinking of returning my generator and using the prius with the addition of a Sine Wave Inverter rated at 1000w running, 1500/2000w peak. However, I had a few questions:
    • How would I plug the inverter into the generator outlet? I couldn't find any adapters.
    • Is this even possible and how much power loss would I have feeding the manual transfer switch which then sends power to the circuits?
    • Perhaps it's not possible to power a 30amp transfer switch from an inverter?
    Thanks.
  2. Frank Perkins

    Frank Perkins Member

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    I have been doing a little more research and it doesn't look like I can simply take a 30amp transfer switch and make it compatible with a 15amp/120v generator or inverter. I found some posts for making homemade cables, but I'm not about to go that route and risk an electrical fire. In fact, they call them "suicide cables" and I'm not going near that mess.

    It looks like my only option is to install a 4 circuit 15amp transfer switch. However, I really need 6 circuits. Still looking for options.
  3. Frank Perkins

    Frank Perkins Member

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    Because there is such little information on this topic, I have a little bit more info to share and maybe someone in the future will find this helpful when found in Google/Priuschat search
    • The only multi circuit transfer panel for 15amp/12o volt connections is the Reliance Pro/Tran 15114A
      • Unfortunately it only has 4 circuits and has no wattage meters. You would have to use a Kill-A-Watt or an inverter with a built in meter of some sort.
      • Here is a video of it in action using a Honda EU2000i generator
      • I emailed an online generator contractor to see if you can wire two of these to one panel and manually alternate between the two. For example Transfer Switch 1 would have Furnace, Fridge, etc and would only have one item powered at once. Transfer Switch 2 would have a: LED Kitchen Lights, Cable Modem, Alarm System and TV (all of which could be operated < 500 watts). Moving the plug from the generator or car to switch 1 or switch 2 would have to manually done (obviously)
      • There is also a 1 circuit option for those looking to power things that can't be "unplugged" like a built in fridge or furnace.
    • I'm still not confident that a Prius -> Inverter -> Manual Transfer switch like the 15114a above will work. It will definitely work from a small 2000w generator like the Honda EU2000i, but I have a few concerns:
      • The max recommended inverter that can be safely run from a Prius is 1000w. I know a few of setup 1500w and 2000w, but I'm going with 1000w as a "safe' option. My fridge has a peak startup load of 1000w and then settles at 200w. The numbers SHOULD work, but the efficiency of the inverters are about 85% and then when you think about the resistance in the cord from the Prius to the Transfer panel to then the actual circuit, I assume there is some drop off in amperage. A $300+ investment in an inverter that won't power something critical like my fridge would be a fail.
      • Possible inverters to use are:
    • Lastly, the best way to actually install the inverter that I found is by Woodman
  4. CygnusX-1

    CygnusX-1 Junior Member

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    I'd be cautious of the Sunforce. I didn't read through all the comments or description, but the last statement of the zon video said that each outlet was rated at just 500 watts. Seems strange that they would have individual outlets rated at 1/2 rating. My biggest concern is if this isn't really two 500 watt inverters in one. The question is, "Are the two outlets in phase with one another?"

    I'm going to guess that they are and they are just warning that the internal wiring to each outlet can't handle the full load of the inverter. Just something to consider.
    jdcollins5 likes this.
  5. Frank Perkins

    Frank Perkins Member

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    That's a good point. I remember reading that as well, but can't remember the source. Unfortunately I'm giving up and going to keep me existing 240v backup generator system. Maybe I'll do an inverter for a fun project but not for house backup.
  6. Randy B

    Randy B Junior Member

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    There are more options. Look up ConVerdant for more power and wiring options.
  7. drysider

    drysider Member

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    You can use the 30 amp switch, but it is designed for 230 volts, so you would only be able to use half of the circuits. The smaller panel would work if you wanted to back-feed a second panel to get the six total circuits you need. Making a custom cable is not difficult...problems usually arise with undersized wires and bad connections.
  8. Frank Perkins

    Frank Perkins Member

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    Just an update on my progress. I have created a 15a to 30a cable and have tested it using my generator through the common 120v outlet. Using my kill-a-watt I was able to validate that I don't need more than 500w to power a combination of the circuits that are enabled through my 10 transfer switch. My next steps:
    Ill post my results later in the week. The plan is: Prius -> Traction Battery -> 15amp cable to 30amp transfer switch -> various circuits in the house (fridge, furnace, tv, internet, etc)
  9. Frank Perkins

    Frank Perkins Member

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    I hooked up the inverter to the prius which then was fed into home transfer switch. I was able to power everything just as I was when I was using the normal generator. The only snag I ran into is that home internet, even though powered, is not working. I believe it's because my circuit panel surge protector and/or cable booster is not powered and it's killing the signal. Ill have to get the electrician to put those items into the transfer switch. My next step is to add some connection cables so I can easily unplug/plug in the inverter. I was scared as sh*t connecting the inverter to the traction battery, especially when the hot lead sparked. Note to anyone setting this up, be sure to have the inverter OFF while connecting it!

    Ill be posting a youtube video soon enough.
  10. DadofHedgehog

    DadofHedgehog Active Member

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    Frank, AIMS used to offer a 2000W pure sine wave inverter (what I got). It's rated for I believe 5000w surge and 2000w constant. Several threads here for that inverter.
  11. Frank Perkins

    Frank Perkins Member

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    Thanks, I saw that too. However, what I read is that the Prius safely only should generate 1000w of power so that's why I stuck with a 1k inverter.
  12. DadofHedgehog

    DadofHedgehog Active Member

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    ...if the power is taken through thee 12V battery. Higher if through the traction battery.
  13. DadofHedgehog

    DadofHedgehog Active Member

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    Let us know how your system works out.
  14. Frank Perkins

    Frank Perkins Member

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    Almost done with my setup. I got the connector installed on the car side. I screwed up hammering down the mechanical connection on the inverter side so I had to order another terminal plug. I hope to have a dedicated thread and youtube video up by the end of the week. Here is a picture of the connector installed on the Prius. More to come soon!

    priusGenConnector.png
    DadofHedgehog likes this.
  15. Frank Perkins

    Frank Perkins Member

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