Controller for water pump

[Tony Tudor]

Have recently installed a v simple arrangement to heat my hot-tub. I have a solar water heater panel on the roof of my garage next to the tub, a pump to circulate the water and a 12v 10w pv panel to power it. When the sun comes out the pump starts and when it goes in it stops. V simple & it works - except for one problem. When there is low solar energy, the pump is activated but does not pump - it just buzzes which of course will burn the motor quite quickly. Can anyone tell me what I need to control the power - to cut off power to the pump if not enough energy and preferably limit the max power too.

The pump is rated at 12v but the manufactures say it will work fine between 9 & 14V
The PV panel is 12v /10w

Many thanks if anyone responds!

[Amy@altE]

My best suggestion is a DTC designed for PV SHW. You put the sensor on the collector, one in the tub, and it will not turn the pump on unless the collector is hotter than the tub. That way you are not only protecting the pump from trying to turn on when it can't, you are also keeping the tub from cooling off in the morning. Art Tec Solar makes them, as does IMC Instruments.

[Mike90250]

A 10w panel will barely produce 8w which is not much for a pump

[Tony Tudor]

Controller for water pump

My best suggestion is a DTC designed for PV SHW. You put the sensor on the collector, one in the tub, and it will not turn the pump on unless the collector is hotter than the tub. That way you are not only protecting the pump from trying to turn on when it can't, you are also keeping the tub from cooling off in the morning. Art Tec Solar makes them, as does IMC Instruments.

Many thanks Amy - will take a look at the products

Tony

[Wy_White_Wolf]

Have recently installed a v simple arrangement to heat my hot-tub. I have a solar water heater panel on the roof of my garage next to the tub, a pump to circulate the water and a 12v 10w pv panel to power it. When the sun comes out the pump starts and when it goes in it stops. V simple & it works - except for one problem. When there is low solar energy, the pump is activated but does not pump - it just buzzes which of course will burn the motor quite quickly. Can anyone tell me what I need to control the power - to cut off power to the pump if not enough energy and preferably limit the max power too.

The pump is rated at 12v but the manufactures say it will work fine between 9 & 14V
The PV panel is 12v /10w

Many thanks if anyone responds!

3 things

1. The IMP of the panel needs to be 1.5 times the amperage requirement of the pump.

2. A Linear Current Booster (LCB) will then help with low output startup.

3. Use a differential temp controller. That will allow the thermal panel to heat up before starting the pump.

[Tony Tudor]

Controller for Water Pump

3 things

1. The IMP of the panel needs to be 1.5 times the amperage requirement of the pump.

2. A Linear Current Booster (LCB) will then help with low output startup.

3. Use a differential temp controller. That will allow the thermal panel to heat up before starting the pump.

Many thanks - shall price up the items you mention & let you know how things work out.

TT