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12v Battery Question

Discussion in 'Gen 3 Prius Technical Discussion' started by reloader775, Jun 4, 2011.

  1. reloader775

    reloader775 Compression Ignition Addict

    Joined:
    Mar 10, 2011
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    Location:
    Orange County
    Vehicle:
    2011 Prius
    Model:
    IV
    What is the max amps you are able to draw off of the 12v battery? I'm looking to install a viair compressor (2 if possible 40 amp draw total). Is this possible without the addition of another battery? Or can the traction battery be used???

    Thanks in advance.
     
  2. direstraits71

    direstraits71 Member

    Joined:
    Jul 17, 2008
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    Location:
    Central Coast California
    Vehicle:
    2008 Prius
    Generation 2 Prius numbers and Generation 3 should be similar. The inverter which runs when the car is in Ready can supply 100Amps to recharge the 12 volt battery and run 12 volt components in the car. If you are talking about having the car in Ready state you can probably draw around 75 Amps if you use large enough wire to connect the load. You will have to carefully measure the startup current of your compressors as there is a 120Amp fuse between the inverter and the actual 12 volt battery in the rear of the car. If that blows you won't be able to start your car until its replaced. So put a smaller fuse in line with your load. Without the car in Ready state the 12 volt battery is quite weak as its only rated at around 30Amp hours. In the Prius the starting current is a maximum of 30 Amps for milliseconds and much lower than that as the electronics start up and since you're just booting computers there's no starter motor drawing large currents hence the small 12 volt battery. There are many threads about using the prius to power inverters. Here's one:

    http://priuschat.com/forums/gen-ii-...242-anyone-use-inverter-need-quick-reply.html
     
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