DC sourced appliances without inverting

hillbillyhog
hillbillyhog Registered Users, Users Awaiting Email Confirmation Posts: 1 ✭
in Solar Beginners Corner #1
Greetings. Led's , chargers, comps, etc run on DC. Anytime you change you have losses. A system starts off DC, is inverted, goes to distribution system, then is changed back to DC. Seems to me it would be simplier and more cost effective to skip the changes.  For low consumption applications? What you think?
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,917 ✭✭✭✭✭✭
    #2
    Define low consumption? In my case I can use as little as 2 or 3 kwh and another kwh for keeping the inverter running. I can't buy many of the appliances in DC and the ones I can are not as good of quality and do not last as long as AC appliances.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • 706jim
    706jim Solar Expert Posts: 523 ✭✭✭✭
    #3
    Don't forget line losses too. Very few appliances can be hooked up directly to a 12 volt battery. In my summer camp, I found nearly a full volt drop with a 500ma load going through maybe 60 feet of #14 copper wire. At the time, I figured I'd need 18 volts in order to run a 7 amp DC TV. My advice: forget about 12 volt appliances and run an inverter with 120 volt appliances.
    Island cottage solar system with appriximately 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing due south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter which has performed flawlessly since 1994. Outback Flexmax 80 MPPT charge controller four 467A-h AGM batteries. Insignia 11.5 cubic foot electric fridge 1/4hp GSW piston pump. My 31st year.
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  • Thom
    Thom Solar Expert Posts: 196 ✭✭✭
    #4
    I have a small system using 12v dc and 120v ac . Charge phones , iPads , dsl , radio batteries with 12v dc. House is wired 120v ac for everything else with a 400w inverter. The inverter is off all night,  on for lights and TV for a few hours a day . Pump water , vacuum, shop tools with a generator .
    Off grid since 1984. 430w of panel, 300w suresine , 4 gc batteries 12v system, Rogue mpt3024 charge controller , air breeze windmill, Mikita 2400w generator . Added 2@ 100w panel with a midnight brat 
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  • NANOcontrol
    NANOcontrol Registered Users Posts: 276 ✭✭✭
    #5
    There was a news item that some major players were working on a new DC standard for the home. As said before many items work on DC. Most of those devices draw current only at the peaks of the sine wave. As these devices multiply it is becoming a problem for the utilities and inverters.  All these little wall warts also draw a couple watts each and that really adds up.  My Energy Star washer consumes 80WH a day just being off.  A home DC buss will someday be popular with the inroads of solar into the market.

    That said, there isn't a large market for DC appliances, and what voltage do you choose to make these in. I run a number of appliances on DC like water heater and dishwasher.  The dishwasher only needs about 80W of AC. The heater consumes the majority of power and that is modified to work directly on DC. My entire kitchen works only on a 400W MSW inverter with the fans disconnected.
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