Pairing solar panels with inverter for pool pump

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Gambit12

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Hi guys,

I would like some advise on what spec solar panels to connect to my inverter. I would like to DIY my pool pump from solar. I don't want to use batteries. Only solar. Inverter will be connected to the pool pump DB for AC supply as 2nd alternative.

Pump spec:

Speck 1.1kW
Operating Watts: 1085w (Tested)
Start-up watts: 1630w (Tested)

Proposed Inverter: Growatt 3000w. Max PV array 1500w. Max open circuit voltage: 102VDC. MPPT range@operating voltage: 30-80 VDC.

https://www.solarwaysuppliers.co.za/wp-content/uploads/2014/01/GROWATT-PDF-NEW.pdf

Questions:

  • I'm thinking of getting 3 x 400 watt panels. Is that fine? What do I need to look out for?
  • Can the inverter operate without batteries connected?
  • If the power generated from the panels doesn't meet the full pump load. Can the balance be taken from the grid?
  • I assume the motor start-up can be powered by AC and then switch to solar for operating power?
Any advice would really be appreciated.

Thanks in advance
Delwin
 
have you thought of installing a dedicated solar pool pump .i looked at it a while back .it wasnt cheap but seemed very efficient .the motors are low voltage hi torque units and dont need huge power to drive them .edit .they come with soft start controller .you then add the required panels for the motor size .
 
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You are going to need an inverter that specifically states that it can operate without a battery, I don't see that on the spec of that Growatt. The spec sheet is also not comprehensive enough to see if it can blend solar and mains.
 
At that rate why not just install it for your house and have the pump hooked up to it? Oh and generally you will need the battery for the inverter so it has something to draw power from when there is no sun or a dip.
 
Lupus said:
At that rate why not just install it for your house and have the pump hooked up to it? Oh and generally you will need the battery for the inverter so it has something to draw power from when there is no sun or a dip.
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he may only be looking at it for convenience like myself .not everyone gets load shedding .i have no need for any form of power backup at all .i was using solar on my borehole untill a few months ago .cheap and efficient .
 
soulie said:
he may only be looking at it for convenience like myself .not everyone gets load shedding .i have no need for any form of power backup at all .i was using solar on my borehole untill a few months ago .cheap and efficient .
Click to expand...
Solar isn't only about loadshedding, it's about moving off the grid as much as possible. Pool pump running off solar is great, but 90% of the house running off solar even better.
 
I won't recommend running that inverter or most of them without battery. 1200w of panels is also far less than the motor startup current and you haven't even included the losses. The inverter mppt can also only take 102v Max which means you will need to run all the panels in parallel so need thicker cable.
 
soulie said:
he may only be looking at it for convenience like myself .not everyone gets load shedding .i have no need for any form of power backup at all .i was using solar on my borehole untill a few months ago .cheap and efficient .
Click to expand...
That would require him to change his pool pump for $$$$$. Cheaper to setup a system for the house and let the pool pump run off that. When I say cheaper I mean more bang for your buck.
 
I think there was a similar discussion somewhere, my suggestion there was: maybe a dc pump running of a solar panel, you wont need the inverter.
 
B-1 said:
I won't recommend running that inverter or most of them without battery. 1200w of panels is also far less than the motor startup current and you haven't even included the losses. The inverter mppt can also only take 102v Max which means you will need to run all the panels in parallel so need thicker cable.
Click to expand...
No, he won't. He'd need thicker cables if he ran it in series.

edit: need more coffee
 
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  • Wow
Reactions: B-1
The_Ogre said:
No, he won't. He'd need thicker cables if he ran it in series.
Click to expand...
Um, series increases the voltage, parallel increases the amps. If you have higher voltage, current is lower, allowing a thinner cable to be used.

P = V x I

Still, 1200W is the same whether it's series or parallel and is not enough.
 
wingnut771 said:
Um, series increases the voltage, parallel increases the amps. If you have higher voltage, current is lower, allowing a thinner cable to be used.

P = V x I

Still, 1200W is the same whether it's series or parallel and is not enough.
Click to expand...
You're right!
 
Gambit12 said:
Hi guys,

I would like some advise on what spec solar panels to connect to my inverter. I would like to DIY my pool pump from solar. I don't want to use batteries. Only solar. Inverter will be connected to the pool pump DB for AC supply as 2nd alternative.

Pump spec:

Speck 1.1kW
Operating Watts: 1085w (Tested)
Start-up watts: 1630w (Tested)

Proposed Inverter: Growatt 3000w. Max PV array 1500w. Max open circuit voltage: 102VDC. MPPT range@operating voltage: 30-80 VDC.

https://www.solarwaysuppliers.co.za/wp-content/uploads/2014/01/GROWATT-PDF-NEW.pdf

Questions:

  • I'm thinking of getting 3 x 400 watt panels. Is that fine? What do I need to look out for?
  • Can the inverter operate without batteries connected?
  • If the power generated from the panels doesn't meet the full pump load. Can the balance be taken from the grid?
  • I assume the motor start-up can be powered by AC and then switch to solar for operating power?
Any advice would really be appreciated.

Thanks in advance
Delwin
Click to expand...
Either go for grid-tied with something like a Solis inverter or get a solar pump. Grid-tied is a much better option unless there is no grid.
 
P924 said:
Either go for grid-tied with something like a Solis inverter or get a solar pump. Grid-tied is a much better option unless there is no grid.
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How do you grid-tie when you can't feed back into the grid? I suppose you can but a lot of solar gets wasted. Buying a new pump is expensive and makes more sense putting that money into the house system that the pool can feed off imho.
 
Lupus said:
At that rate why not just install it for your house and have the pump hooked up to it? Oh and generally you will need the battery for the inverter so it has something to draw power from when there is no sun or a dip.
Click to expand...
I don't want to spend too much on a system for the house. My aim to save in electricity cost for the pool pump only which currently is around R500-R600 pm. Why do I need a battery? It will still be connected to the grid and draw from it when it needs more power?
 
Gambit12 said:
I don't want to spend too much on a system for the house. My aim to save in electricity cost for the pool pump only which currently is around R500-R600 pm. Why do I need a battery? It will still be connected to the grid and draw from it when it needs more power?
Click to expand...
Until there is no power? If Eskom is down and your system is running? Also a lot of inveters need the battery for backup especially if they're running in solar mode.
 
wingnut771 said:
How do you grid-tie when you can't feed back into the grid? I suppose you can but a lot of solar gets wasted. Buying a new pump is expensive and makes more sense putting that money into the house system that the pool can feed off imho.
Click to expand...
Most new inverters can limit export to 0, including the Solis range. If you do it this way, you can grid-tie to your whole house and get the benefit of solar even when the pump is not running. Or you can limit the solar production to only what the pump uses, but that would be a waste.
 
if i had gone solar for my pool it would have paid for itself in 3 years .pumps are around 6k and panels depends on what you buy .i would save around R600 to R850 per month just on thevpool pump .i also have no use for an inverter system for the home .the motors run from 70 volts upwards
 
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