The Delta-T Booster™ II (aka Booster or DTBII) is a differential temperature (∆T) controller with current boosting functionality. It has been designed specifically for solar pumps and DC motors that utilize a 12 V or 24 V photovoltaic (PV) solar module as the power source.


The DTBII comes standard with Thermo Dynamics':

  • Solar Boiler System
  • Solar Boiler Module
  • MagDrive Solar Pump
  • Direct Drive Solar Pump


How It Works
The Booster™ holds the voltage of the PV module at approximately 15 VDC in a “12 V nominal” system, or approximately 30 VDC in a “24 V nominal” system. If the motor voltage rises above 15 V (or 30 C), the BoosterTM allows the PV voltage to rise with motor voltage. The PV voltage should be 15 V (or 30 V), except in the early hours of the morning as the sun rises above the horizon, and in the late hours of the day when the sun sets.

During low sunlight conditions when the PV module does not produce sufficient power to drive the Solar Pump™ continuously, the Booster™ stores the electrical energy from the PV module, and then releases it in a sudden burst of power to cause rotation of the pump. This “jolting” feature also serves to start the pump earlier in the day, when it might remain at rest due to static friction after resting overnight.

The DTBII uses two temperature sensors (10,000 ohm thermistor) for differential temperature control. By comparing the two tempera- tures, the DTBII ensures that the Solar Pump is only activated when there is energy to be gained, that is, when the solar collector is hotter than the storage tank. The DTBII has high and low temperature limits, and failsafe protection in the event of an open or short circuits. The DTBII provides all the control functionality necessary for a solar thermal system powered 100% by the sun.

Electrical Specifications

Voltage (nominal): 12 or 24 VDC* 
Voltage (maximum): 22 or 44 VDC
Voltage (typical): 15 or 30 VDC
PV current (maximum): 4 amps


*The DTBII is only to be connected to a 12 V or 24 V PV module. For servicing purposes a current controlled DC power supply (set at 20 or 40 VDC) can be employed.



Delta-T Booster II - Solar Pump Controller