Inverters

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Alaska Man
Alaska Man Solar Expert Posts: 252 ✭✭
in Off Grid Solar & Battery Systems #1
I'm curious as to power consumption of various inverters.

I have a Xantrex Freedom series 3,000w 12 volt inverter. When it's on it is drawing 2.0 amps out of my battery. I just read on another thread there is a guy whose inverter draws 0.13amps??

Is my inverter just a pig, what are others seeing for draw?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
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    Re: Inverters

    Your inverter is a pig. It's sucking down 24 Watts of power (more or less).
    My VFX3524 uses 20 Watts. But there are others that draw even more (like 30 or 40 Watts).

    You have to compare output capacities to be fair; that 0.13 Amp inverter could be only 300 Watts and that current rating may be for 'standby' mode.
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #3
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    Re: Inverters

    To start with a 3000 w x 12v inverter is just plain silly.. the current draw under full load will be close to 300a.. if you go above 1000w you should use 24v. avove 3000 w 48v.
    about 2 amps would be about correct for a inverter above 1000w. it will usually be somewhere between 20w and 30w.
    A 100 to 600w inverter will draw about 300ma., or somewhere between 150 to 400ma.
    You need to match inverter to load . using a 3000w inverter to power a 300w load is not good as inverrters are ineffecient below about 70% output.

    TSW inverters nearly always draw more (50 to 100% more)idle current than MSW inverters..
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #4
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    Re: Inverters
    Cariboocoot wrote: »
    Your inverter is a pig. It's sucking down 24 Watts of power (more or less).
    My VFX3524 uses 20 Watts. But there are others that draw even more (like 30 or 40 Watts).

    You have to compare output capacities to be fair; that 0.13 Amp inverter could be only 300 Watts and that current rating may be for 'standby' mode.

    Most of my house is wired to one electrical panel. I have a second panel that supplies only 5 outlets, for the washer, vacuum, power tools and other high draw items. Right now the two panels are both supplied by my outback inverter with a tare consumption of 20 watts. 20 watts all day long is 480 watthours per day... that's as much as my sundanzer freezer draws in a day!

    My plan is to buy a second small inverter (with low tare loss) that can remain on 24/7 and supply my main electrical panel. I would only turn on the outback a few hours per week as needed for laundry, vacuum, etc.

    My research has shown that Victron makes a 700 watt (continuous) pure sine inverter with a tare loss of 5 watts (2 watts on standby). Problem (for me) is that it has built in outlets and is not NRTL listed for hard wiring into a residence (listed for marine use).

    For hard wiring, exeltech makes a well regarded 600 watt (continuous) pure sine inverter with a tare loss of 8 watts.

    Neither of these inverters has a built in charger.

    Let us know if you find any more attractive options.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #5
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    Re: Inverters

    Exactly so, vtMaps.

    The Outback has a standby mode wherein it draws 6 Watts. A Morningstar 300 Watt inverter draws this much in full-on mode, and a tiny fraction of it when in standby. The output difference is a factor of more than 10X. And it leads to the question of how often do you need that full output power?

    For me running a conventional refrigerator was the main point of the system. As such the need was there for a greater than 1kW inverter in order to handle the start-up surge. The price and power usage of the 3.5kW inverter was the same as for a smaller (OB) one, and the large inverter could also handle the (conventional) pump load. Simultaneously if need be. Thus I designed the system to power that big inverter all the time. In standby the savings are small since it would be on for most of the day anyway to run the constant draws such as the Internet connection. Having it cycle on/off for about 10 hours overnight (running approximately 1/3 of the time) offered no big savings in power.

    No two systems are ever exactly alike, so the equipment choices need to be tailored to individual needs including such 'intangibles' as lifestyle and availability. There is a greater variety of equipment available now than when I put my system in, and it's much cheaper (especially panels).
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  • Alaska Man
    Alaska Man Solar Expert Posts: 252 ✭✭
    #6
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    Re: Inverters

    I did oversize that's clear now. I wish I knew then what I know now. Since the Xantrex is only a few years old, I'll live with it.
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