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Attaching 12v/0.6A to house bank 12v /435A?

Discussion in 'Technical Discussion' started by P46-Curaçao, Apr 6, 2016.

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  1. P46-Curaçao

    P46-Curaçao Senior Member

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    I have my boat completely solar powered, except for the aircons. Most of my 110v equipment uses a large inverter, but most of them are only switched on when I'm at the boat, the rest (fridge, pumps, stereo, etc) is 12 volt.

    Now I discovered, that some items have a 110v to 12v adapter, and I was wondering if I could eliminate the adapters, so there is no power loss of the adapters and there is less need for the inverter...

    My question is, (just to be sure) if I can attach equipment, for example my security camera, that uses 12v/0.6A direct to my house bank 12v /435A without damaging it?
  2. Capt Ralph

    Capt Ralph Senior Member

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    I'm assuming that is 12 V Direct Current (battery operation) for the camera;

    If your camera requires 12Vdc and may draw up to 0.6 Amps of current.
    Your battery bank can provide 12Vdc and deliver a 435Amps of current flow to connected options.
    No problem here, Your camera should work over 700 hours before the battery needs re-charging.

    If your camera requires 12VAC, Don't tie it in. It may well fail the smoke test.


    I like the idea of digging deeper into your 12Vdc/120Vac options.
    Some refers do use a 12Vdc compressor and have a builtin Converter making 120Vac work.
    Some refers do use a 120Vac compressor and have a builtin Inverter making 12Vdc work.
    Double check the manuals & schematics or read some data right off of the compressor to help determine what voltage and style (AC vs DC) would most effetely run the equipment.


    Big inverters are great but they do waste some power doing their thing (norm 80 - 90% efficient), Then if the fridge is converting it back to 12Vdc it's loosing some more power before the poor compressor gets a drop of power.
    Removing it from the loop MAY be more efficient in the long run. How long (weeks, months, years) before any payback (your labor, materials) is realized is a guess.
  3. P46-Curaçao

    P46-Curaçao Senior Member

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    Ok great Ralph, and yes, I only want to direct-connect 12Vdc 'toys' to my house bank, instead of run them via a 100-240Vac to 12Vdca adapter! I think it eliminates the need to use my inverter, so that saves some more battery capacity too!

    FYI have no problems with the capacity, but the more I can save, the better it is... I'm detailing my system now, have some time left after rebuilding the engines...LOL
  4. bobhorn

    bobhorn Member

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    The problem may be in the device's allowed voltage range. Does 12 Vdc mean exactly that or is there some leeway? Remember that when charging, the battery voltage will be about 14.4 Vdc.
  5. P46-Curaçao

    P46-Curaçao Senior Member

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    Good point, during daytime, the Solar panels are charging 14.4 Vdc, so I need something that gives 12Vdc continually, will check on that, thanks!
  6. bobhorn

    bobhorn Member

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    No user feedback. You may want to buy two or three for backup. On the other hand, check your 12 V devices, they may be able to accept the charging voltage.
  7. P46-Curaçao

    P46-Curaçao Senior Member

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    You are right, but just as an example for a solution, it would be OK?
    Most 'toys' only have the adapter with info, so better be sure than sorry...(fire)
    I buy one plus a spare at a reputable supplier!
  8. Capt Ralph

    Capt Ralph Senior Member

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    Again, it's in the mfg's specs.
    I would assume anything rated at 12Vdc has a tolerance to go 15Vdc with no problems.
    Contact the mfg to cya.

    If your trying to get away from inefficient equipment, why tie in a Dc to Dc converter?
    Just the nature of another device uses wattage. The heat sink design is not there for good looks.
  9. P46-Curaçao

    P46-Curaçao Senior Member

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    I will look into it, but as mentioned, on most 'toys' there is no real info available...
  10. Metatron

    Metatron New Member

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    If you are using standard, household type 12v devices, they can probably deal well with the extra charging voltage overhead ( 15v ) ok. However, if you have a lot of inductive devices such as electric motors using the 12v power, you can get very sharp and high voltage spikes which can damage 12v equipment which is not designed to deal with the inductive spikes.

    I think most automotive type equipment would be OK, but I would be hesitant about 12v equipment which was not protected. I think you might be wise to put a choke on the power lines to any suspect equipment.
  11. P46-Curaçao

    P46-Curaçao Senior Member

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    Everything is non motorised, what do you suggest as a choke on the power lines?
  12. bobhorn

    bobhorn Member

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    Checked the 12 V cigarette lighter adapter for our Garmin car GPS and it's rated for 10-40 Vdc.
  13. Pascal

    Pascal Senior Member

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    We have a number of DC powered cameras and other related gizmos powered by 120 wall adapter. I looked into getting rid of them but voltage variation are an issue. Gave up
  14. Capt Ralph

    Capt Ralph Senior Member

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    Some wall adapters are mini transformers converting 120Vac to 12Vac.
    Then some adapters are crude 120Vac to 12Vdc converters.

    You just can not assume when you read on a gizmo "12v" that means 12Vdc or battery voltage.
  15. P46-Curaçao

    P46-Curaçao Senior Member

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    Yep, but the Garmin GPS works on 5Vdc I guess
  16. bobhorn

    bobhorn Member

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    The output of the cig lighter adapter is 4.75-5.25 Vdc.
  17. P46-Curaçao

    P46-Curaçao Senior Member

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    Ok, I will look into it more closer, thnx!
  18. P46-Curaçao

    P46-Curaçao Senior Member

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    Just what I was thinking, most of my 'toys' are 5 or 12 Vdc...