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mtofell1's avatar
mtofell1
Explorer
Sep 15, 2017

Convert 120V to 12V

I Just got a macerator to empty tanks at home and am a bit stumped on powering it. I know I can pull right off the battery but am wanting to run it off my house/shore power. Reasons being I have two tank outlets on my 5th wheel so wiring up to both is a hassle. Also, I mainly bought this thing just to avoid lines at dump stations and so if I use my RV at home I can dump. I may wire up the RV at some point but for now I'm just looking for home use.

Anyway, I'm so familiar with house wiring that I'm embarrassed to even be asking these questions. I've installed electric panels in houses and wired too many things to count (I'm a building inspector by trade so I even got all the permits to ensure I did it right :))

So, what I'd love to find is a simple device I could plug into my outlet at home and wire up the two legs of this macerator to. In searching I'm getting confused by all the terms - transformer, inverter, converter - 12V, 24V.

I've got to think the part I need is simple to find but an internet search seems to just turn up inverters (I know what this is and know it's going the wrong way). From what I do understand I think I need a transformer - like for a doorbell, but the 20A rating and wire size on this macerator tell me I need way more than something for a doorbell.

Thanks for any advice.
  • Ivylog's avatar
    Ivylog
    Explorer III
    Sep 15, 2017
    Bumpyroad wrote:
    just get a little jump starter battery jobby and your problem is solved. no muss, no fuss.
    bumpy

    X2 or a good battery charger that you need to carry in your RV anyway.
  • Bumpyroad's avatar
    Bumpyroad
    Explorer
    Sep 15, 2017
    just get a little jump starter battery jobby and your problem is solved. no muss, no fuss.
    bumpy
  • valhalla360's avatar
    valhalla360
    Navigator
    Sep 15, 2017
    I get a little nervous when you claim electrical expertise but don't understand a transformer doesn't convert AC to DC. But anyway...

    Looking online most units seem to draw about 20amps (confirm before starting).

    Simple solution: Pick up a set of jumper cables long enough to reach from the RV battery or even your truck battery. Attach alligator clips to the leads from the pump motor.

    When you use it, connect the alligator clips to one end of the jumper cable and connect the jumper cables to the battery. Quick and easy. Nice thing about jumper cables is even with pretty long distance, 20amps is nothing and they come with easy clamp on connectors for the battery terminals. You could make your own up with smaller wires but if you go with small wires, you have to check voltage drop to make sure the wires can handle the amps.

    You could do the same thing with one of the emergency jump start boxes to allow you to shorten the length. Plus you have a jump start backup.

    A converter or large battery charger could work but seems kind of complicated for what you are trying to do. If you do go this route, make sure the battery charger doesn't need a battery in the loop. I have a little 6amp one that checks the battery voltage before starting. If you just connect the leads in a circuit, it doesn't do anything.
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Sep 15, 2017
    Maybe it's better to start this out easy and ask what the spec sticker says on the macerator for AC power amperage...
  • MrWizard's avatar
    MrWizard
    Moderator
    Sep 15, 2017
    what is the amp draw on the maceator

    buy an RV converter connect the output to the mace
    and extension cord on the input,

    when you finally get around to wiring the 5vr
    you will have a spare converter, IF ever needed

    ME i would probably make some long 12v power cord and just connect to the 5vr battery
  • naturist's avatar
    naturist
    Nomad
    Sep 15, 2017
    Do you have shore power at home? Why not just hook into the fiver's existing 12 volt system like it was designed to do and let the existing converter in the trailer do what it was designed to do, i.e. provide 12 volts off shore power?
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Sep 15, 2017
    BTW A transformer won't work because it has AC output and you need DC.
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Sep 15, 2017
    Search on 120v to 12V converter. ie The output is DC. Here's one. A common auto battery charger could also work.

    Of course you could just make an extension of 2 wires to run from the battery back to the macerator location. Either permanent wiring or not.

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