Remote alternative site - solar PV or small generator?

Discussion in 'Ham Radio Discussions' started by MW1CFN, Feb 2, 2018.

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  1. MW1CFN

    MW1CFN Ham Member QRZ Page

    I am lucky enough to have a semi-permanent field location from which to escape the potential for my investment in radio to be spoiled by others' RFI.

    I am interested mainly in operating 10W or less digital modes, with the occasional venture into SSB. I expect the operating pattern to be a day or evening of operating every weekend or so.

    The site is not (audio) noise sensitive, but it is preferable I keep noise to a minimum.

    I could go solar, have a small test PV system at home, and no discernible RFI problems, though I may not be able to place TCVR and PV quite so far apart in the alternative site. At very close range, charge controller RFI is moderate. I can only really install a maximum of one 250W panel, but I could partly make up for that with a large capacity battery.

    Or I could go with a small petrol generator. I am at the point of preferring this because it offers longer operating potential. But I wonder what experience people have with 'pure' sine wave inverter generators. Any RFI problems? Other problems? Typical lifetime of generators, assuming regular care?

    I'd be interested to hear from those with lots of practical experience, especially if you are in a less than a sun-drenched desert location!
     
  2. KY5U

    KY5U Subscriber QRZ Page

    I think Honda makes a silent 230 generator. It's not 100% quiet but about 85%. Solar is a charging system that relies on batteries to store the charge. If the sun is not out, you need battery capacity to use.
     
    MW1CFN likes this.
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I'd think for QRP operations up to 24H at a time, a PV panel/regulator and a good battery is much more convenient.

    Any kind of genset will require you bringing fuel to it, which is kind of a chore unless you happen to carry the fuel around anyway. The Honda EU series (I have one, an EU2000i) are very quiet and their inverters generate no RFI I could ever find, but they still need gasoline, and of course occasional maintenance.
     
    K1TGX, MW1CFN and K7JEM like this.
  4. KK5JY

    KK5JY Premium Subscriber QRZ Page

    I have used PV for both home and portable HF operations. If you choose the charge controller carefully, you should not have any detectable HF noise. Some charge controllers are actually designed to be RF quiet. Even if you don't want to spring for such a controller, you could always just turn off the charge controller while you operate from batteries, then enable it when you are done, and let the batteries recover while you are at work the next week.

    Small generators, on the other hand, are rather tough to make RF-quiet, especially if your location is already quiet. And it's not really practical to shut off the generator while you are operating, unless you run from batteries, which takes you back to PV. :cool:
     
    MW1CFN likes this.
  5. W3MMM

    W3MMM Ham Member QRZ Page

    Agreed.

    I'd have the deep-cycle battery fully charged before heading out. That'll give you a large block of time to operate, even if there's no sun. If there is sun, you charge the battery with the solar panel while operating, thus extending the life for the weekend.

    I have a Honda generator as well; it produces little RFI and I expect it to last for decades with typical engine care (particularly to ensure the carburetor doesn't get clogged; which is an issue when using fuel mixed with methanol.) But hauling gas around, if you don't have a pickup truck, is smelly and inconvenient.

    If the generator has some other purpose at the getaway, and you can get gas near your getaway, then I'm sure it could be put to good use with ham radio at some point.

    I'd go with the PV solution, even knowing it isn't perfect - it may leave me stranded without power. (Note, here's where you might look at if/how you can recharge your deep-cycle radio battery from the car's battery. If you can do that, then you could go for a REALLY long time, days and days possibly, without a generator and without any sun to charge via the PV panel)
     
    US7IGN likes this.
  6. N3HGB

    N3HGB Ham Member QRZ Page

    My "shack" is essentially this. I have deep cycle batteries aboard my boat, shore power, engine, and solar charging. Shore power is some RF noise, the engine is a LOT of it, and the solar is pretty silent audio and RF. Solar panels are pretty cheap now. Get a good Morningstar MPPT and some traction batteries and you'll be loving life. QRP isn't needed if you don't want it, I run 100 watts off batteries all the time. If I am doing digital modes the computer's steady drain actually accounts for more battery used than the radio does. Do NOT cheap out on the charge controller - that is the one thing where it will hurt to go bargain basement hammy hambone.
    If you do go with wet cell traction batteries, get an IOTA charger for them. You can use a genset if needed to top them off for the few times the sun won't be enough and the IOTA chargers really do well on big wet cells. You also very much can string a cable out to your car for a charge. Not the best way, but it beats nothing.
     
    MW1CFN likes this.
  7. W1KU

    W1KU Ham Member QRZ Page

    This use case seems almost ideal for solar.

    My very rough math suggests you could get about 12 hours of operation for ~600 Watt hours; that could be 50% discharge on a 12V 100Ah battery. If you operate once a week, that power could be replaced with less than 4 hours of full sun on the 250W panel per week.

    Adding one more battery would get you 24 hours of operation with 50% discharge which would get you through two weeks no sun plus reduce battery wear on sunny weeks with only 25% discharge.

    If you shut off the charge controller during operation and can avoid running an inverter, the site could be extremely RF quiet. The only noise source would be the computer to run the digital modes and whatever DC-DC converter is needed to run it, if any.
     
    MW1CFN likes this.
  8. N0TZU

    N0TZU Platinum Subscriber Platinum Subscriber QRZ Page

    Seems like a great fit for solar power. Even in a less than sunny location a week is a lot of time to recharge.

    I have used the Honda 2000i series generators extensively while camping and during a few power outages. They are quiet by generator standards, but it is still a blessed relief to the ears when they are shut down.
     
  9. MW1CFN

    MW1CFN Ham Member QRZ Page

    Thank you very much for the replies thus far. Extremely useful and considered responses.

    The PV seems a better option, and significantly cheaper and maintenance-free, relative to buying and running a decent Honda generator.

    I wonder if I could ask about the DC-DC converter for laptops. Any suggestions of type there, or is any cheap-and-cheerful one OK in terms of quality and RFI generation?

    Again, very grateful for the useful replies.

    J.
     
  10. W1KU

    W1KU Ham Member QRZ Page

    I've used an Igo Juice 70W for more than a decade. I haven't checked it for RFI, but others have said it's clean. Just make sure you can find, adapt, or make an appropriate tip for your computer. (e.g., I have to chain two adapters to connect to my current laptop.)

    This type of converter seems to be getting harder to find as inverters have become small and inexpensive and more commerical aircraft have AC outlets in seat.
     
    MW1CFN likes this.

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