Powering inverter from 12V port.

Discussion in 'Prius c Technical Discussion' started by jtgd, Oct 9, 2019.

  1. jtgd

    jtgd Junior Member

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    I've noticed how I can sit parked in READY with the A/C on and the engine will just kick on as needed to charge the battery. I'm wondering if the same is true for drawing power from the 12V socket.

    I'm facing this PG&E power outage tomorrow and I'd like to keep the fridge on. It needs about 150-200W and I have a 200W inverter, but the owners manual says I can't draw more than 10A and that's only 120W. Can I assume there is a 10A fuse? Not sure how to get the 18A I need, but one question I have is if I just leave it in READY, will it start the engine as needed, or is the 12V system separate?
     
  2. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    You’ve got the right idea as far as power availability on that 12v port. That pulls power from the 12v battery, which is charged/replenished by the DC/DC converter. The converter pulls from the big traction battery. If that traction battery goes low, the engine starts and charges for a few minutes. The power continues trickling through.

    Now the bad news is that you aren’t likely to keep your fridge running through this arrangement. While it may only need 150W to run, they typically need 2-3x as much power momentarily to start, and then the listed draw to continue operating. You aren’t going to get that past the 10A fuse on that lighter plug line.

    Many inverters can handle a momentary surge much higher than their listed output- but you would do well to confirm the particulars for yours. It might still be suitable to the task.

    What you’ll definitely need to change is the connection from the inverter to the 12v battery. Make a connection appropriate to the current you’d be pulling and this can work the way you are hoping.
     
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  3. jtgd

    jtgd Junior Member

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    Thanks for the info.

    From other posts I gathered what I needed to give it a try. I did not even attempt to use the power outlet. The inverter came with clamps and I connected to the post in the fusebox. It ran the fridge just fine. Starting at 80% battery it took about 20 mins to get down to 20%, engine kicked on for 20-30 seconds, another 10 minutes before it kicked on a second time. Inverter was not at all warm. (It's 750 watt)

    So that test was a success and I am very comforted to know I can survive an extended power outage if I need to. It's 3:40 and the power is still on but PG&E might still pull the plug. I'm ready.

    I would think my full tank of gas should last at least a week. VERY efficient compared to a gas generator, although generators produce more power, but this is all I need to tide me over, and the inverter was only $43 compared to hundreds for a generator.

    I never realized my Prius would be so useful beyond just being a great car!
     
  4. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Excellent, glad it works! Now that you know how, go buy 10 more of those inverters so you can hook up your neighbors for fun and profit.
     
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