I am thinking of putting a pure sine wave inverter in my ARES kit

Discussion in 'General Technical Questions and Answers' started by KK4QGN, Dec 7, 2013.

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  1. KK4QGN

    KK4QGN Ham Member QRZ Page

    I am looking to finally put a kit together but I am trying to figure out if a Samlex PST-600-12 can:

    1) handle the load of a sony vaio mini netbook and a yaesu FP-1023 power supply that is hooked to a yaesu ft-1900
    2) give me a decent amount of operating time per battery.
    3) handle the rigors of ARES work
    4) can be used for extended periods of time I estimated 8-12 hours on 8-12 hours off depending on manpower.

    If this would work I would also like to know what battery type is best for such requirements. I know it is a lot to ask about but I want a way to keep my netbook charged during operations. also I intend to later on add a yaesu ft-817nd and power suppy to this setup.

    thank you in advance,
  2. N0IU

    N0IU Ham Member QRZ Page

    Gotta ask...

    Why would you want to run your battery into an inverter and then into a 12 volt power supply and then to your radio when you can run your radio directly off of the 12 volt battery? Everything you add between the battery and the radio is just going to suck the life out of the battery.

    I don't own a Sony Vaio mini netbook, but I would imagine that someone makes a 12 volt car adapter that you can use to power the netbook.

    As far as what type of battery, a good deep-cycle marine battery will allow you to run for days on a single charge. They are not small. They are not light. They are not cheap. But remember, if your objective is to set up a station that could possibly be used for extended periods of time off grid in an emergency situation, this is not the time to skimp. Lives could depend on it one day.
  3. NN4RH

    NN4RH Premium Subscriber QRZ Page

    Concur. To operate an FT-1900 for "8 hours" assuming receive time of 7 hours and transmit time of let's say 1 hour at 10 watts output requires about 15 amp-hours of battery capacity before the voltage dips below about 12 volts. You'll need at least a 30 or 35 Amp-Hour deep cycle battery for that. Limit your transmit time to the lowest power and only essential transmissions and your receive will work for a couple days on such a battery. Much longer if you just turn it off when you don;t need it.

    If you have an inverter and a power supply in between, you'll need up to four times as much battery capacity!

    My battery backup for my FT-1900R in the shack is just an 18 amp-hour SLA battery that gives me enough power to receive operate intermittently with occasional limited low power transmit for a quite long time. Then there's also an FT-817 and several 7 A-Hr batteries I can fall back on.
  4. AA4HA

    AA4HA Premium Subscriber QRZ Page

    If you can stick with DC only operations it will indeed be much more efficient. Not losing watts converting 12 VDC up to 120 VAC and then back down to 12 VDC. Probably using DC/DC converters all the way.

    Sine wave inverters create a PWM (pulse width modulation) waveform through the switching transistors and amplifier to create an approximation of a sine wave. Even so there are harmonics created by the transistors switching through rise/fall. This can generate EMI up to tens or hundreds of KHz. Be prepared to deal with some interference, particularly at the lower bands like 160 and 80 meters.

    Switching supplies (AC/DC) work pretty much the same way. They rectify the incoming AC power and then run it through a pair of transistors at a much higher frequency (tens of KHz) and use a tiny transformer to step the voltage down, run it through a bridge rectifier/ regulator, maybe a filter cap or two and then provide a DC output. The advantages of switchers are that they can be fairly efficient at low loads, small because the transformer is intended for high frequency operation (the same reason that aircraft use 400 Hz power systems). And with less loss due to heat.

    Other than my boat-anchor radios I run everything off of 12 or 24 VDC with batteries on float charge. The chargers are linear supplies (no switchers). Even my shack lighting is 12 VDC.
  5. NN4RH

    NN4RH Premium Subscriber QRZ Page

    I just check - yes there are such things available. They cost anywhere $15-$45. 12 VDC in, 19.5 VDC out.
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