Lots and lots of sun here! Nothing at all like building high-reliability off-grid power systems for frigid mountain top comm sites during my 25 years in Alaska.
Speaking of which, I generally try to avoid wind generators in snow and ice country. All it usually takes is a bit of ice on the blades and before you know it, the bearings are shot. And charge controllers for wind generators are much more problematic and inefficient than solar controllers. "My advice is free and worth every penny!" -Christopher Erickson Network Design Engineer Waikoloa Village, HI 96738 N19°57' W155°47' > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Josh Luthman > Sent: Friday, January 15, 2010 10:08 AM > To: WISPA General List > Subject: Re: [WISPA] Solar suggestion for ultra low use site? > > Lot of sun down there in Hawaii, Christopher? > > Josh Luthman > Office: 937-552-2340 > Direct: 937-552-2343 > 1100 Wayne St > Suite 1337 > Troy, OH 45373 > > "The secret to creativity is knowing how to hide your sources." > --- Albert Einstein > > > On Fri, Jan 15, 2010 at 3:05 PM, Christopher Erickson < > [email protected]> wrote: > > > Maybe start with one or two 75 watt panels and an MPPT > > charger and see where that gets you. And it isn't against > > the rules to visit the site to charge up the batteries > > with a Honda 1000i generator once in a while during winter > > if the site begins to fall behind a bit in charging. > > > > The MPPT chargers ar a tiny bit more expensive than the > > old technology chargers but they do a better job of being > > able to charge with feeble sunrise, sunset and overcast > > light. They can even charge the batteries when the panels > > are putting out less than 12 volts. They probably add > > about 5% to 10% more charging every day than old style > > chargers. And they will never overcharge your batteries. > > > > "My advice is free and worth every penny!" > > > > -Christopher Erickson > > Network Design Engineer > > Waikoloa Village, HI 96738 > > N19°57' W155°47' > > > > > > > -----Original Message----- > > > From: [email protected] > > > [mailto:[email protected]] On Behalf Of AJ > > > Sent: Friday, January 15, 2010 9:42 AM > > > To: WISPA General List > > > Subject: Re: [WISPA] Solar suggestion for ultra low use site? > > > > > > As far as sun hours are concerned, this is in the Boise, > > > Idaho area which > > > falls within Zone 4 with an average 4.5 sun hours per day. > > > The site itself > > > should be in full sun the majority of the day as it sits on a > > > bench above the downtown area. > > > > > > The "inversion" haze is pretty bad in the winter - > however - not many > > > parades, marathons, races or marches (other than the Boise > > > Holiday Parade) between November and April... > > > > > > Power is consistent across the board - all of the radio > and control equipment work directly off of 12 VDC. > > > > > > Batteries are free to us as surplussed by the utility > donating them. > > > > > > I *completely* agree with security screws on panels - the BLM > > > sites here > > > have heavy L channel over the edges of the panel with pad locks to > > > completely secure the panel in place. > > > > > > We work on roughly a $500 annual operating budget solely from > > > donations - > > > whatever we end up with would need to be scalable so we can > > > start out with a very basic system and ramp up over time. > > > > > > Thanks! > > > > > > -AJ > > > > > > On Fri, Jan 15, 2010 at 12:21 PM, Christopher Erickson < > > > [email protected]> wrote: > > > > > > > Latitude and average cloud cover will be factors. > > > > > > > > I would use MorningStar MPPT solar charge controllers. > Get every > > > > last watt of solar charging you can manage. Each controller can > > > > handle one to three 75 to 200 watt panels. If you end > up needing > > > > more than three panels, add controllers and panels until > > > > sufficient charging is obtained. > > > > > > > > Avoid as many power conversions as possible. Power conversions > > > > never have 100% efficiency and many of your precious > watts end up wasted as heat. > > > > > > > > 6V golf cart batteries are the best bang for the > battery buck and can be deep cycled much better than 12V > automotive-style batteries > > > > because they have much thicker plates. > > > > > > > > Dusty and/or snowy areas can be a problem. If so, schedule > > > > regular PMI visits to inspect and clean the panels. > > > > > > > > Use security screws on the solar panel mounting brackets. Solar > > > > panels are starting to become a popular theft item. > > > > > > > > "My advice is free and worth every penny!" > > > > > > > > -Christopher Erickson > > > > Network Design Engineer > > > > Waikoloa Village, HI 96738 > > > > N19°57' W155°47' > > > > > > > > > > > > > > > > > -----Original Message----- > > > > > From: [email protected] > > > > > [mailto:[email protected]] On Behalf Of AJ > > > > > Sent: Friday, January 15, 2010 8:38 AM > > > > > To: WISPA General List > > > > > Subject: [WISPA] Solar suggestion for ultra low use site? > > > > > > > > > > Thought I'd tap in to the collective intelligence of the WISP > > > > > group for this question... > > > > > > > > > > > > > > > Looking at setting up a solar powered VHF ham repeater in the > > > > > middle of a > > > > > metro area for infill coverage... Site is land locked by > > > > > ghetto on one side > > > > > and rail tracks on the other - commercial power is > not an option. > > > > > > > > > > We have available a dozen or so surplus Alpha 85 amp hour gel > > > > > cell batteries > > > > > which test out at roughly 90% capacity (PM swaps)... > > > > > > > > > > The first thought was to simply charge up a battery for each > > > > > event we work > > > > > in the downtown core, drop by the site and swap out whatever > > > > > battery is in place.. Not quite the most efficient plan. > > > > > > > > > > Our next thought was to place a decent sized array, maybe > > > > > 300-400 amp hour, > > > > > then supplement with an off the shelf solar panel or two > > > to maintain a charge... > > > > > > > > > > Our equipment consists of an ancient GE MastrII repeater > > > > > turned down to 25 > > > > > watts and an NHRC controller. Standby draw is 125 mA, > > > > > transmit ramps up to about 3.5 amps... > > > > > > > > > > Duty cycle is key here - we work perhaps a dozen events a > > > > > year within the > > > > > coverage of this repeater for about 4 hours each on about a > > > > > 10% duty cycle > > > > > (TX 6 out of every 60 minutes). The rest of the time the > > > > > repeater sits idle > > > > > and will not transmit unnecessarily (no IDs or anything > > > > > unless it's actively in use)... > > > > > > > > > > What is out there on the market for a low cost solar site? > > > > > > > > > > Thanks! > > > > > -AJ > > > > > > > > > > > > > > > -------------------------------------------------------------- > > > > > ------------------ > > > > > WISPA Wants You! 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