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DC to DC converter on Prius C: need factual answer

Discussion in 'Prius c Technical Discussion' started by Jollyman, Feb 1, 2013.

  1. Jollyman

    Jollyman New Member

    Joined:
    Dec 28, 2012
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    Vehicle:
    2012 Prius c
    Model:
    Two
    What is the specification for the DC to DC converter that converts the traction battery 144VDC to charge the 12V battery as in how much power can it continuously handle?

    I have seen references to about 1000 watts for the Prius, but as we all know the PriusC is "downsized" in almost every way. Is the DC to DC converter downsized too?

    This is of course for running a small inverter. I am well aware of the required current in trying to make 120VAC from 12VDC. Very roughly you can multiply the AC current times 10 and that is what you will need as 12VDC current from the battery. I don't want to overload the PriusC system. All of the discussions on the web seem to relate to the regular Prius.

    PART 2 - Academic Question
    The proper way to do this of course would be to use the 144V battery directly with a high voltage inverter designed for a home solar power system using high voltage batteries. This would require only 1/10th the current and would eliminate one of the conversion steps. Can the 144V battery be reasonably accessed, perhaps through the testing port I have heard about? Of course Toyota (quite properly) wants to prevent people who don't know what they are doing from getting anywhere near the HV battery and system, but if you DO know what you are doing, is it possible? Does the testing port present HV battery voltage? How much current can it handle?

    OF COURSE THIS IS ALL FOR ACADEMIC STUDY ONLY. HIGH VOLTAGE IS DANGEROUS, POTENTIALLY FATAL (pun intended) AND NO ONE SHOULD ACTUALLY ATTEMPT TO MODIFY OR USE TEST PORTS ON THEIR PRIUS THEMSELVES.

    So There!
     
  2. Jollyman

    Jollyman New Member

    Joined:
    Dec 28, 2012
    14
    6
    0
    Vehicle:
    2012 Prius c
    Model:
    Two
    DC/DC inverter question solved indirectly: The Prius has a 100 amp fuse for the DC/DC inverter. I looked for the same fuse on my C and the owner's manual shows it to also be a 100 amp fuse. Reports say the Prius service manual lists output for the Prius converter as 80 amps or less, so a 100 amp fuse makes sense.

    Since the C has the same 100 amp fuse, it might be capable of the same 80 amps to charge the 12V battery.

    If this is true then allowing for some inverter losses this equates to about 900 watts maximum continuous output from an inverter. This would allow the C to keep the 12V battery from completely discharging over time. If you kept your AVERAGE power to safely less than 900 watts it should be possible to pull a momentary surge power much higher than that to start a load like a freezer. You will need a power meter (Kill-A-Watt etc.) to make sure.

    All posts are my opinion only. I have not tested this. If you do it is at your own risk, etc.

    Also on part 2 above, it appears there is no "test plug" or service port. It is a disconnect plug and only serves to disconnect the HV battery from the chassis wiring for service or disassembly of the vehicle.