@epierre You can use a Peltier element to power this board. Like this one:
http://www.ebay.com/itm/TEC1-12706-12V-60W-Heatsink-Thermoelectric-Cooler-Cooling-Peltier-Plate-Module-/121349774916?hash=item1c41029e44:g:mukAAOSwDNdVrg-U
following this thread loosely.
I have the following sensors and they seem to be accurate to some degree:
http://www.aliexpress.com/item/DFRobot-Capacitive-Analog-Soil-Moisture-Sensor-3-3-5-5V-Corrosion-Resistant-with-Gravity-3-Pin/32574020064.html?spm=2114.01010208.3.2.P99ddH&ws_ab_test=searchweb201556_0,searchweb201602_1_10037_10017_507_10033_10032_10040,searchweb201603_1&btsid=8d3b5e46-a069-441a-a1f7-491ae7e317e1
and they are much easier to work with Arduino compared to Watermark stuff. Anyone agree?
I think I found the problem. I think it misbehaved because of an illegal character in the "HOSTNAME". Changed the hostname yesterday and It was still alive this morning even if I have not pinged it.
I would think that the "heavy lifting" of regulating the actual output power of the charger would be a function of the charge controller itself? Maybe you could tie into / control that somehow with your own microcontroller as brain / interface? Maybe they expose some API, serial, or other method of interfacing with their hardware?
What are/were you using for charge controller?
Also, what is "CT" in this context?
I have read a bit here and there about solar (and related moving around and controlling of power, eg. batteries, charge controllers, etc...), as it is something I plan on doing "eventually" although I have no direct experience as of yet. So I will be following this thread with interest.
Really interesting, maybe I could build something cool around the Arduino HeatpumpIR (https://github.com/ToniA/arduino-heatpumpir) library I've been building. Right now I'm integrating it with Domoticz (http://www.domoticz.com/forum/viewtopic.php?f=34&t=7179#p69647).
I'm an ex-Microsoft employee from Finland (resigned about a month ago).