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Too much voltage drop accross Enginer On/Off - Switch/Breaker

Discussion in 'Prius PHEV Plug-In Modifications' started by overlap, Aug 22, 2010.

  1. overlap

    overlap Junior Member

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    At least for my liking and across my particular SNC, PICC, DZ47-100H, D100A switch. It has material, 0.10 voltage drop (!!!) with a modest/approximate 50 AMP

    (This is wrong, it's closer to 15 AMPs, 53v*15A=795W)

    charge as seen by my Kill-O-Watt's 850 Watt input charge. Current thinking is to replace it with a 100 AMP fuse. I do want an on/off switch - an open issue for the time being.
     
    #1 overlap, Aug 22, 2010
  2. seilerts

    seilerts Battery Curmudgeon

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    A 100 amp breaker will have some level of internal resistance. You also have resistance at the connections. I saw a 100 amp breaker out there listed at 0.0005 ohm resistance; your data shows 0.002 ohm for breaker + connection (R = .1V/50Amp). Not clear that there is really a problem here?

    And don't fuses have higher resistance anyway?
     
    #2 seilerts, Aug 23, 2010
  3. overlap

    overlap Junior Member

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    I would think not at least at the lower currents, but then higher-current heat will negatively impact anything. Under a full 5000W converter draw, I will check the v-d.

    Hmm, this is what I want, an extremely efficient, high-amperage gauge that derives the amperage from extremely accurate and minuscule voltage-drop. Anyone have a link to a nice dash-mounted gauge?

    Not for my 2KW battery pack that has a 50 AMP fuse inline under the previously stated circumstances. With a voltage drop on the 4KW pack and zero v-d on the 2KW pack, a constant pack voltage difference was observed. Yesterday I bought two 50 AMP fuses and still need to buy a nicely pre-cut piece of flat brass stock (or copper if I can find it) to make two battery connectors to avoid cutting up the four-terminal strap and then work the fuse between each of the two cell-pairs.

    I'm also going to visit a Marine store since they must deal with reasonably heavy electrical components for electric trolling motors and more.
     
    #3 overlap, Aug 23, 2010
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