12v dc solar controller

[southsidedelite]

http://www.jc-solarhomes.com/solar_heating_controller.htm

PV Systems with 12 Volt Battery :
Another feature of the AC/DC controller is battery protection used
with PV power supplies. If the differential is set too low or the
sunlight is insufficient to keep a battery charged the controller
shuts down before the battery is depleted. The controller will shut
down when the voltage drops below 8 volts and will not come back on
until the battery has been sufficiently recharged (around 14 volts).
The differential off adjustment allows the user to adjust the maximum
heat gain with minimum power requirements. The best adjustment will
depend on the size of the PV power supply and the demands made on the
pump. Closed loop systems generally require less power than open loop
systems. A PV panel with a maximum power output between 10 and 100
watts is good for most applications. I am using a 50 watt PV panel
with my MTD solar heating system.

WITHOUT A BATTERY BUFFER between a PV panel and a pump the supply
voltage fluctuate between 0 volts and 19 volts. This extreme voltage
fluctuation puts undue stress on most DC pumps. Some people think that
a PV panel alone is sufficient to regulate pump speed with sunlight
intensity. HOWEVER, total dependence on sunlight intensity for
regulation is not a good idea. Scattered clouds can turn off a pump
before heat is collected from a collector. Bright sunlight in winter
is another consideration. Without a differential controller bright
sunlight turns on a pump at full speed before the collector has had
time to warm up. This bright/cold condition could circulate cold water
through a heat storage system and diminishes net heat gain. This is
why differential controllers should be used with PV power supplies
with battery back up systems. Since battery protection is built into
the circuit expensive deep cycle batteries are not required.


This new (November 2008) AC/DC Differential controller fulfills a
variety of needs at a competitive price. These are the features of the
AC/DC differential controller with monitors.
Adjustable off differential
Battery protection with PV power supply
Monitoring of Collector Temperature
Monitoring of Storage Temperature
DC pump control with PV power or Battery Charger
AC pump control with 9VDC adaptor
Calibrate temperature sensors
Easy to operate
Easy to troubleshoot
Satisfaction guaranteed
If you are using a 12VDC photo-voltaic power supply with a battery
back up you can use the same 12VDC supply to power your pump as you
use to power the differential controller. Battery protection is built
into the circuit so if the supply voltage drops below 8 VDC the
controller will be deactivated to prevent battery damage. After the
battery has recharged up to 14 VDC the pump will be allowed to come
back on if the collector temp is 18 F above the storage temp.
If you are powering an AC pump you will need a 12 VDC wall
transformer to power the controller. A simple jumper wire between pin
3 and pin 2 of the control board is all that's needed to convert the
AC pump controller to a DC pump controller. A wall transformer is
available for $5 if you need one.
CONTACT:
can...@optonline.net