I want to be run my pool pump directly off solar panels. I know I will need a 1 HP, variable speed DC pump and about 4 panels.
Can I just connect the pump up to the panels or do I need to some sort of controller. There is off the shelf systems but they seem very expensive and they have a controller but I dont know exactly what the controller does (if anything).
Can I just connect the pump up to the panels or do I need to some sort of controller.
No, your pump won't be able to start off the panels. The panels cannot store energy and won't be able to supply the momentary surge current. The panels also don't maintain a specific voltage, rather it depends on load and sunlight. You'll need a controller and a small battery or capacitor as well as the panels and pump.
Personally I'd just get an off-the-shelf system.
The starter is the bit I am not clear about it but I understand I need it.
I would have thought a variable speed DC motor would be fine with the variable current as long as it stayed within the motors limits.
I haven't used a motor like that so I can't comment. However the start up surge also includes the head of water that the motor needs to push.
Be aware that the open circuit voltage of a "12v" solar panel can be as high as 22v, thus without a solar controller your DC motor needs to tolerate a wide voltage. Also without a solar controller the solar panel voltage will not be at its maximum power point and you could be losing around 1/3 of the power.
why do you need such a setup?
So I don't have to pay for electricity to run my pool pump.
How would this be different to the traditional installation of solar panels.
As I have panels and a pool
No inverter required. Op won't have to pay a sparky 10k to connect 3 wires, can do it hims lf
All of what the other guy said but also when it is cloudy the pump will only use available solar power and not draw grid power.
@[Deactivated]: I see… I want to do a similar thing except with hot water.. so hot water will always use solar power and only draw on grid power should it need to.
I read somewhere that involves a diverter of some sort. Haven't investigated it in too much detail
@Archi: Hot water is pretty easy, just connect the panels to the hot water service. When it gets hot enough the thermostat will disconnect the panels. Problem is what happens when you don't get enough sun?
It sounds like a hit and miss idea. If you want to go cheap just get some panels and a microinverter. They can just plug into a PowerPoint. Then put a timer on your pool pump so it comes on in the middle of the day
It is best to run it off a controller, as solar output can be variable. Over-voltage and current will kill your pump pre-maturely. Even if you just get a cheapie one off ebay, it will be better than none at all.
I bought a used solar panels off gumtree, got myself a $15 controller and a used car battery. I run my garden lights off that, since they are all 12V.