Grease for HV terminals

Discussion in 'Gen 2 Prius Technical Discussion' started by Siber Pir8, Apr 21, 2020.

  1. Siber Pir8

    Siber Pir8 Junior Member

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    Hi all,
    What grease is recommended to protect the HV pack cell terminals and the copper plates?
    Thanks
    Simon
     
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    IIRC the Repair Manual doesn't recommend any? Not saying that's the final word, just a thought.
     
  3. jerrymildred

    jerrymildred Senior Member

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    I've had my gen 2 open. There was no grease on any terminals. Instructional videos don't show or mention it.

    However, if I lived very much closer to the ocean than I do, I might consider it. Then again, everything else would be corroding, too. I spent more time fighting rust than doing anything else when we lived on a small island. Or was it termites. Maybe 50-50. :D
     
  4. Siber Pir8

    Siber Pir8 Junior Member

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    I rebuilt by battery a year ago, coated in a small amount of vasaline and there is already some corrosion in some areas. There are no leaks inside, as I didn't want to have to take them out again and clean them up.
    I do live in the uk and rain is always here.
     
  5. AzWxGuy

    AzWxGuy Weather Guy

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    You could probably put a little dielectric grease (for spark plug boots) on the just the part of the thread where the nut would seat. Try not to put any grease where it would be exposed to airflow from the cooling fan. Dust magnet.
     
  6. sam spade 2

    sam spade 2 Senior Member

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    Dielectric grease is an insulator.
    Contrary to what a lot of people seem to think, it should NOT be put on the conducting surfaces of ANY connection.
    It is intended to be put on the OUTSIDE of the connector or connection AFTER it is tightened or connected.

    In one of my motorcycle forums recently there was a guy who was having trouble with his spark.
    Turns out that instead of anti-seize on the plug threads he used dielectric grease.
    He was actually feeling the spark on various metal parts of the bike. :eek:
     
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  7. ChapmanF

    ChapmanF Senior Member

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    At the other end of the spectrum from dielectrics, there are greases made to be conductive.

    Motorcraft XG-12 is a nice one.

    I'm not necessarily convinced it would be indicated for use on HV battery terminals. It is pretty thick, but I don't know if it thins when hot; letting a conductive grease dribble down a module might be asking for an isolation fault.
     
  8. MickyMatter

    MickyMatter Active Member

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    There's a difference between contact grease and pole grease:
    The first one contains copper or aluminum particles and isn't isolating. This can be put between the contacts to prevent corrosion between them.
    The latter is isolating and is used to build a "shield" to the environment to prevent corrosion from outside. It should be applied as last step, if it won't be pressed out of the contact area by tightening screws.
    Maybe someone likes to translate this from German: Kontaktfett | Modellbahntechnik Aktuell
    (Or search for another source already in English)

    SM-G950F ?
     
  9. Siber Pir8

    Siber Pir8 Junior Member

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    The copper contact keep going really green so the grease would need to go on these. What about white lithium grease spray?
     
  10. sam spade 2

    sam spade 2 Senior Member

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    Well that means that either the conducting surfaces weren't cleaned good to begin with OR some containment is getting in from the outside.

    Unless made specifically for conducting connections, NO GREASE should be put on the conducting surfaces because most all common grease is an insulator.

    Something like dielectric grease or one of the spray on battery terminal protection products can be applied to the OUTSIDE.
     
  11. Dxta

    Dxta Senior Member

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    During my rebuilds, I used silicon grease on the terminals and bus bars to prevent corrosions in future.
     
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