Yes on all counts. This unit would be described as a simple hysteresis
controller -- it doesn't pulse the charge current, it simply turns
charging on if the battery voltage is less than full charge, turns
charging off when that voltage is reached, and turns charging back on
when battery voltage has dropped some pre-set amount. Chargers like this
are, by their nature, free of RFI, because there's no square wave to
generate RF trash. Several years ago, a local ham pointed me to this
product, which does the same thing, but is rated for a lot less current.
https://www.amazon.com/Sunforce-7-Amp-Charge-Controller/dp/B0006JO0XI/ref=sr_1_1?srs=2601531011&ie=UTF8&qid=1465406526&sr=8-1&keywords=solar+charge+controller
The more efficient charge controllers of which Bill speaks are MPPT
controllers; they have a DC-DC converter that converts the relatively
high panel voltage at low current to lower voltage at the higher current
that the battery can accept. This allows a large battery to accept more
charge in a shorter period of time. By their nature, they use square
waves, so they can be noisy, and most MPPT charge controllers ARE noisy.
The Genesun MPPT controllers create very little RF noise, and won't be
heard in most installations. My solar panels are next to my 160M
antenna, so I need a choke on panel side of the controller to prevent
noise pickup on that antenna. That's a pretty extreme condition. :) So
I'd call the Genasun controllers RF quiet.
73, Jim K9YC
On Tue,6/7/2016 6:12 PM, Bill Frantz wrote:
I have been using a solar charge controller from CIrKits
<http://www.cirkits.com/scc3/>. The kit comes in a 20A version and
there are modification instructions for 40A, 60A, and 80A. I have the
20A version and have noticed no RFI in my suburban QTH. The higher
current modifications change some of the circuit resistors to keep the
RFI low, so low RFI was one of the design goals.
This controller feeds full panel current to the battery until the
voltage reaches the float voltage and then floats the battery at that
voltage. This techniqueis a good for lead-acid batteries but is
probably not appropriate for lithium family chemistries.
It is also not the most efficient way to charge a lead-acid battery.
Higher efficiency can be achieved by charging at a slightly higher
voltage and only reducing the voltage to the float voltage when the
charge current becomes low. With my 7.5A rated panels, I can recover
the batteries charge in a day after spending a weekend contesting at
100W, so the additional efficiency is not a major concern. The charge
system also works well on field day at QRP power levels.
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