I'm still trying to solve an electrical control problem. I've got a 100w/12v panel powering a small 12v water pump feature. I purposely eliminated a battery from the system because I don't want the pump running all night. The system consists of the panel, a 24v-12v transformer, on/off switch, and pump. In this configuration the system works perfectly, except the pump tries to push water when lower voltage is being produced. To give the pump a break, I added a low-voltage disconnect switch after the transformer that stops power supply to the load when the supply is less than 10.5v and re-connects when it returns to 12v. This worked but created too much on/off cycling, so I tried another that turns off at 10.0v and reconnects at 10.7v, but it just did a lot of clicking and the pump didn't pump. So the question is, what device will automatically shut down the pump at night and give the pump a rest when the PV is producing low voltage. Thanks.
Electrical Control Advice Needed
- Thread starter LarryJ
- Start date
I think this may be an inherent problem while running without a battery. The solar panel is not a consistent energy source that is why there is cycling.
Why is there a 12-24 volt transformer? Is that because he panel puts out more than 12 volts. How many amps does the pump draw by the way.
Why is there a 12-24 volt transformer? Is that because he panel puts out more than 12 volts. How many amps does the pump draw by the way.
Yes, the transformer is there to protect the pump. The first pump burned up because I didn't realize the PV produces more than 12v.
I understand why the pump cycles, and cycling is fine provided it doesn't do it so frequently. In full sunlight the pump would cycle on for 11 seconds and shut down for about 6 seconds when the 10.5-12v LV disconnect was installed.
The pump draws 3.5 amps.
