Topband: [Bulk] Re: Remote pre-amp power source

[Grant Saviers]

The way to squeeze the most watt-hours out of panels and into batteries 
is with MPPT regulators.  "Maximum power point" regulators that adjust 
rapidly to the real time insolation.  A series regulator is throwing 
away W-H.

See  http://en.wikipedia.org/wiki/Maximum_power_point_tracking

some interesting references particularly the thesis that describes what 
he built with the PIC based controller.

OTOH, a 15 to 20 watt panel connected to a 100 A-H battery really 
doesn't need a regulator.  Just check the water every few months.  I had 
such a setup run a community water system radio control of the well 
pumps and the battery would last about 5 years 24 x 365, with about a 
50ma load.  Worked in San Jose, CA.  Might not work in Seattle. :-(

Grant KZ1W
Redmond, WA

On 9/25/2014 4:33 PM, Don Kirk wrote:
> Hi Bruce,
>
> Their are numerous methods used for sizing solar panel systems, and using
> one of the common methods provides the following for your application as
> follows :
>
> Using a battery charging efficiency factor of 120%, and Portland Maine as
> the location (winter average = 3.56 sun hours/day) .  And designing for a
> reserve capacity of 3 days (3 days of no sun), with a minimum battery
> capacity of 50%.
>
> If designing for continuous power applied to the preamp (24 hours per day)
> : Required battery capacity = 18.7 Ah, Solar panel = 1.05 amps (almost a 20
> watt panel).
>
> If designing for 15 hours of continuous service (using a day/night
> controller) : Required battery capacity = 11.7 Ah, Solar Panel = 0.66 amps
> (approximately a 10 watt panel).
>
> The above method is somewhat simplistic (does not take into account how
> cold temperature impacts the capacity of the battery, etc.), nevertheless
> it provides some reasonable numbers to put things into perspective.
>
> I'm sure you will think the panel and battery are large, but that's what it
> takes to handle continuous service during the winter when day light is
> minimum.
>
> Note : solar panels really operate like a constant current source versus a
> constant voltage source, therefore a typical solar panel for 12 volt
> battery charging will have an open circuit voltage of around 21 volts but
> this is under a zero output current condition.  The maximum output current
> of a solar panel is when you have it's output short circuited but it's
> current at max power is not much less than its short circuit current.  An
> easy way to characterize what kind of panel you have is to measure under
> bright sunlight the short circuit current, and the open circuit voltage of
> the panel.
>
> Don (wd8dsb)
>
>
> On Thu, Sep 25, 2014 at 2:55 PM, <k1fz at myfairpoint.net> wrote:
>
>> Hi Don,
>>
>> Pre-amp requires 12-18 volts at 130ma. (low band DXing- nightime use)
>>
>> This  solar charger puts out 20 volts that could be reduced to 15 volts
>> with a three legged regulator.  I was hoping to find a pre-assembled
>> charger & battery, but may have to build one.
>> http://www.harborfreight.com/15-watt-solar-battery-charger-68692.html
>>
>> 73
>> Bruce-K1FZ
>>
>>        What is the operating current and voltage of the preamp you plan to
>> use?  Since it sounds like the preamp will be powered on all the time this
>> information will be key in the selection of the battery capacity and solar
>> panel rating.
>> Don (wd8dsb)
>>
>> On Thu, Sep 25, 2014 at 1:30 PM,   wrote:
>>
>>        Anyone using, or know of a source, for a compact battery with solar
>> cell charger, to power a remote antenna pre-amp ?
>> 73 Bruce-K1FZ
>> www.qsl.net/k1fz/pennantnotes.html
>>
>> _________________
>> Topband Reflector Archives - http://www.contesting.com/_topband
>>
>>
>> _________________
>> Topband Reflector Archives - http://www.contesting.com/_topband
>>
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband
>