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Best inverter

Discussion in 'Gen 3 Prius Main Forum' started by PriusKyle, Oct 16, 2022.

  1. PriusKyle

    PriusKyle Junior Member

    Mar 12, 2022
    2011 Prius
    Hey all,

    Finally thinking of getting an inverter for my 2011 prius mod 3; wanted to get feedback and recommendations. What do you use and what has been your experience?

    From my preliminary research, PURE SINE WAVE is the way to go as it produces clean power for sensitive electronics like computers etc. is that correct?

    Next, minimum of 1000W? I was thinking of doing 2000W; I realize this depends on what I’ll be using it for etc., i..e., microwave vs. mobile phone. Want long term and can handle pretty much any appliance. Will 1000W be adequate? What do you think?

    Better to use connectors that have alligator clips or the small loop to be more permanently attached to battery. A manufacturer had a warning on its inverter not to leave the inverter on when car is off which worries me and makes me not want to have the inverter bolted onto the battery indefinitely. Is the alligator clips the way to go and just connect inverter when you need ac power?

    One more thing, I noticed some people place a fuse or breaker of some sort in the connection to battery; guess for safety reasons but is this really necessary but I do see some inverters that have these protections built in the inverter; in case it doesn’t, do I need some sort of fuse in the setup?

    Thanks in advice!
  2. ChapmanF

    ChapmanF Senior Member

    Mar 30, 2008
    Indiana, USA
    2010 Prius
    Hard no on "alligator clips" for the amount of power you are thinking to draw. 1000 watts at 12 volts is close to 85 amps. For that you need wire close to the size of your finger and solid, bolted connections. The idea of 2000 watts would push that to 170 amps (which is more than the car's DC/DC converter can supply), and even heavier wire.

    Yes on sine wave. There used to be a significant price difference that pushed people to consider "modified sine" (which would more accurately be called modified square wave), but the price difference has shrunk to where there is really very little point in skimping and then always wondering which of your things will and won't operate well on the resulting power.

    It is sensible to avoid leaving the inverter on when the car is not in READY. You don't need alligator clips for that. At the range of power you are considering, one option would be to use Anderson connectors suitable for the necessary current (say, 100 amps if you go with a 1000 watt inverter, 200 amps if you go for 2000 watts). You'll securely bolt one connector to your battery and fuse, and the other to the inverter, and now you can unplug it when not in use. Or you can add a switch or a relay (again, it must be adequate for the current to be drawn, and that will be a big switch or big relay).

    But the details of the inverter matter. If you buy one that really is off (drawing no power) when turned off, you can just leave it connected, and turn it off. But many of them will do something annoying like show a front-panel display when off, and be a constant drain to the battery. So it is well worthwhile to comparison shop and make sure you get one where off is really off. Then you don't need the big switch or big relay or anything to unplug.

    The Xantrex ProWatt SW that I'm using is definitely off when off, so I just leave it permanently connected. I don't know about others you might be considering.

    Many inverters also contain a feature to turn themselves off if your battery voltage drops to near-drained. Should leave you enough to be able to start the car. That is a worthwhile feature.

    The one I am using has a socket on the front panel to connect a remote control. I've wired that to a switch on the dash. That gives me control to turn the inverter on or off, and because it is a feature of the inverter itself, again there's no need for a giant relay to do it. This model inverter also allows an "enable/inhibit" signal with the remote control. I have that connected to a separate "low voltage disconnect" that I have set for a voltage between normal resting battery voltage and the voltage the car produces when READY. So the LVD automatically turns on when the car is made READY, and turns off with a settable time delay after the car is turned off. That way, I don't have to do anything special to turn the inverter off when I turn the car off, but I can also get out briefly, for refueling or a rest stop, without the power immediately going off.

    A fuse is important, as close to your connection to the battery as possible, to protect against damage to the wiring you've added from there to the inverter. The wire from where you tap to your fuse needs to be heavy enough for worst-case current. If you tap from the place I recommend—the car-cable side of the 140 amp fuse built into the + battery post clamp—you can treat 140 amps as the worst case.

    Here's a post with some more details on how I approached it. This thread had more details on setting up the remote control.



    You can see the 80 amp MAXI fuse I have used on the inverter wiring. That is actually slightly small to get the full rated power out of my 1000 watt inverter, but I don't really expect to load it that high. I've never blown that fuse. I don't think the MAXI style comes in ratings above 80 (I've seen some web pages saying 100 is available, but I can't vouch for it), so I would have needed a different style of fuse block to go higher.
    #2 ChapmanF, Oct 16, 2022
    Last edited: Oct 16, 2022
    jzchen and spudnut like this.
  3. spudnut

    spudnut Active Member

    Oct 4, 2016
    Idaho Falls/Pocatello, ID
    2012 Prius Plug-in
    Plug-in Base
    Get a name brand, one that is used by full time "off griders", Like Xantrax, Outback, MorningStar, to name a few. Everything Chapman says is spot on. I have an idiot light, a LED tail lite that reminds me to shut the inverter down when I get to my riding area and disconnect my ebike's charger, so far so good, 3 years now.