Battery meter / USB port installation

Discussion in 'Power - Site Power/Batteries/Generators/Solar' started by drgiese, Apr 28, 2018.

  1. drgiese

    drgiese Member

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    Aug 6, 2016
    Northern California
    Why not?

    I'm sorry for such basic questions. I really don't have a good working knowledge of electricity.
     
  2. NMroamer

    NMroamer Active Member

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    Apr 21, 2016
    Albuquerque NM
    An inverter takes 12 volts DC and starts it pulsating so it can be stepped up to 120 volts AC. All this consumes power through the components. Not practical to make one that can supply more than just a few amps of power. Would be very big and heavy.
    That is what a generator is for.
     
  3. rabird

    rabird Howdy!

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    TX
    I've found this http://circuitwizard.bluesea.com/
    I input 12v, 8A (80% of fuse rating), 30' from batt to plug and back.
    I left the 3%, fixed, 105C temp.

    yielded 10g, you could use a bigger fuse if you like and stay with 10g.

    an inverter designed for cig lighter plug may be up to 100watts, that is not much, no coffee maker, no hair dryer, maybe phone/laptop charger (read its specs), as mentioned, 120 watt bulb uses ~1A @ 120v AC but uses ~10A @12v DC (bit more when inverter is used due to losses from inverting).
     
    drgiese likes this.
  4. Adam H

    Adam H Active Member

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    Aug 22, 2015
    California
    Ok, say you want to run a 100 watt, 120 volt light bulb through the inverter:
    -100 watts at 120 volts would = ~.85 amps
    -.85 amp draw through an inverter would = 8.5 amps @ 12 volts
    - Inverter is about 85% efficient which would increase the 12 volt amp draw to almost 10 amps
    So when stepping voltage up the amps increase fast. An easier way of looking at it is figure out the amps the 120 volt appliance will take and multiply by 10 to get the 12 volt amp draw, that will get you in the ball park.
    I'd be surprised if that plastic cigarette light will handle more than 10 amps @ 12 volts, so a 100 watt, 120 volt light bulb is all it might be able to handle.

    Hope this helps,
    Adam
     
  5. NMroamer

    NMroamer Active Member

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    Apr 21, 2016
    Albuquerque NM
    I answered your question in post #4
     
  6. drgiese

    drgiese Member

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    Northern California
    Yes, you did. Sorry, I missed that part of your post. I was distracted by the fuse issue. Thanks so much for your help!
     
  7. NMroamer

    NMroamer Active Member

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    Apr 21, 2016
    Albuquerque NM
     
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  8. drgiese

    drgiese Member

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    Northern California
    Thanks, Adam! I'm starting to understand. I guess the plug/inverter is not as useful as I'd hoped. I think I'll still be able to use my 12v fan, though.
     
    Adam H likes this.
  9. Drvred

    Drvred Member

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    I installed that exact item. I mounted in the cabinet beside the fridge, connected to the wires for the missing water pump.
    The lights are bright, but I just consider them great night lights. The amperage draw is negligible, so I haven't worried about a switch.
     
    JPBar likes this.
  10. drgiese

    drgiese Member

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    Aug 6, 2016
    Northern California
    Yeah, I'm not worried about the brightness of the lights; my daughter always wants a nightlight, so it would serve that purpose. I was worried about the draw, though... but you say it's negligible, so that's good. Thanks!
     
  11. Katskamper

    Katskamper Active Member

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    Nov 21, 2015
    Fort Worth, TX
    this is my project for Sunday too.
     
  12. Drvred

    Drvred Member

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    May 3, 2017
    The light is LED blue, so you don't even notice it except when you wake up at night.
     
  13. roybraddy

    roybraddy Well-Known Member

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    King George, Virginia
    I never had any good luck using the cheap 12VDC sockets from the auto parts stores for pulling anything over 5AMPS or so on a continuous basis. The plug would get hot and melt down on me..

    What I did for these type of connections was to get one of those matched PLUG and SOCKETS from AMAZON just to be used for your converter plug source.

    The BLUE SEA 1015 Socket and Plug combo look like this

    [​IMG]

    When they are matched to fit this allowed me to draw high DC current for long periods of time without over heating... Your 12V panel may have the same unit in it so all you would need is the matching PLUG... I think the BLUE SEA number for that is 1010 also available from AMAZON...

    For a POWER CONVERTER however it would be best to hard wire the converter 12VDC directly into the 12V Distribution system or even better directly to the battery terminals... the 12VDC leads should be as short as possible but you should keep the Inverter inside out of the weather. Putting the Inverter next to a battery is a bad idea however as the battery emits explosive fumes... The 120VAC cables (Drop Cord) can be as long as you need. 12- 15feet etc... Not much voltage drop on the drop cords.



    I use what is called BOAT CABLE for these kinds of projects. The BOAT WIRE has two conductors with a covering and I use either the 14GA or 12GA size wires.

    Looks like this from AMAZON - comes in the various gauge sizes and wire colors
    [​IMG]

    Then you use the hand crimped on BUTT connectors or supplied ring terminal connections to go around 12VDC Bus bars or other tie in points...

    The FRAME GROUND is good to use in the RV world as it is in most cases wired directly to your battery negative terminal. It is ok but sometimes you have to drill a hole and tap in the proper screw/washer to go to the frame. It may just as easy to go all the way back to the battery using the boat cable etc...

    PEP BOYS sells a frame tap and drill combo kit for this in various sizes that looks like this... Found this very useful for ground to the trailer frames where you need it... Then I would use a ring terminal on the wire and a star lock washer that bites into the frame...
    [​IMG]


    Tricks of the trade hehe

    Roy Ken
    [​IMG]
     
    Last edited: May 6, 2018
  14. roybraddy

    roybraddy Well-Known Member

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    King George, Virginia
    I made a corner in my POPUP trailer where the HOT WATER heater is located for my 12VDC Project distribution panel... I can route all of my project wiring to this location...

    This uses on of those BLUE SEA Fuse panels for ATC fuses and I also have two 12VDC BUS BAR with covers for hooking up heavy current wiring. The POS is painted RED and the NEG is painted BLACK. I fuse the line coming from the main battery switch with one of the BLUE SEA fuse blocks... All of these has the lug terminals that fits the ring terminals I use...

    [​IMG]

    This helps alot to run my 12VDC projects.

    Radio guys always have 12VDC projects hehe...

    [​IMG]

    [​IMG]

    [​IMG]


    With all of the 5/16 inch lugs just about all of my 12VDC wiring uses the ring terminals...

    Of course this is all over-kill for your single project but if you planing of doing many more project this could all come in handy for you... I am always adding something here to mine...

    Roy Ken
    [​IMG]
     
  15. tenttrailer

    tenttrailer Art & Joyce - Columbus, O

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    Thornville, OH
    I had the same outlets/meter. I put a momentary switch on the plus side of the voltmeter. I did not think I nneded the meter readin all the time.
     
  16. roybraddy

    roybraddy Well-Known Member

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    King George, Virginia
    Here is a drawing I did for friend who was wanting to put a small Power Inverter to run his home entertainment items...

    [​IMG]

    The idea here was to install the Power Inverter close to the batteries and then run wire mode hiding the drop cord back to the Home Entertainment area and also back to a table top if needed to hide the drop cord near the master bed for things...

    Roy Ken
     

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