Trying to save on electricity costs, so I was wondering about this.

I have a 750kw 5Amp swimming pool pump. Can I get a 100AH battery, 1000kw Inverter and a 2x 540 Solar Panels to run my swimming pool pump from solar?

The idea is that the battery will just act when the pump is starting up, I will set the pump on a timer and only start the pump when their is full sunshine?

 

Thoughts?

There are not a lot of inverters that will start a pump (without plenty of over-speccing). You need around 3-5x the power for 1-2 seconds to start the pump, low frequency inverters have a better chance of doing that.

13 hours ago, McGuywer said:

Trying to save on electricity costs, so I was wondering about this.

I have a 750kw 5Amp swimming pool pump. Can I get a 100AH battery, 1000kw Inverter and a 2x 540 Solar Panels to run my swimming pool pump from solar?

The idea is that the battery will just act when the pump is starting up, I will set the pump on a timer and only start the pump when their is full sunshine?

 

Thoughts?

Any 1.8Kw will start a 1Kw depending ON THE USAGE OF THE HOUSE.  That is why grid tied and hybrid is nice.  If power is a little low then the grid helps it going. In the case of totally off grid and solar only the total Kwhr is important.  Then it becomes a chain effect

Kwhrforpump = KwhrFromPanels(AC component) - KwhrUSEDBYHOUSE.

Then one should have sufficient PV and Kwhr  Inverter.
 

The column below is an example where left is import from the grid right is export.
 

0.226	0.199
0.039	0.614
0.013	0.471
0.077	0.439
0.22	0.051
0.276	0.19
0	1.136
0	0.856
0	1.248
0	1.177
0	0.914
0	1.143
0.007	0.557
0.003	0.745

4 hours ago, Erastus said:

Any 1.8Kw will start a 1Kw depending ON THE USAGE OF THE HOUSE.  That is why grid tied and hybrid is nice.  If power is a little low then the grid helps it going. In the case of totally off grid and solar only the total Kwhr is important.  Then it becomes a chain effect

Kwhrforpump = KwhrFromPanels(AC component) - KwhrUSEDBYHOUSE.

Then one should have sufficient PV and Kwhr  Inverter.
 

The column below is an example where left is import from the grid right is export.
 

0.226	0.199
0.039	0.614
0.013	0.471
0.077	0.439
0.22	0.051
0.276	0.19
0	1.136
0	0.856
0	1.248
0	1.177
0	0.914
0	1.143
0.007	0.557
0.003	0.745

I think you misread the question.

54 minutes ago, P1000 said:

I think you misread the question.

Oooops,

You are right.  In theory you can.  In practice when you pump starts  it uses a lot of power. That is why I said 1800Kw unit. Its referred to inrush current. I do not have the exact values but it can be measured.

Doing it "your" way is moving +/- 70% to China for batteries over the life of the batt.  Then you hope and pray they last longer than the paper you get with it and the paper is worth what is written on it.

Many will shoot me again  but your best bet is to get a grid tied inverter 3Kw and the when the pump is not running the fridge is using it etc.  Then it become lego.  Next you get more panels and next you ask to feed back.  If they struggle to let you feed back and you want "some help" shout I would love to see the arguments munics got and how they will treat it.

Then perhaps we can win the battle and more can do the same.

 

The maiin thing is do your best to start. two panels one grid tie inverter and you startr saving.  THen you can use Eskom $ to pay for you inverters and electricity.  Every Kw save you 1$

With batteries yo pay a percentage to China and just read the charging problems live span unbalanced batteries people wright about on this page.

Grid tied simple easy and you can start with less $ than  when you buy batteries

 

Edited December 1, 20214 yr by Erastus

Hi @McGuywer

If your goal is to reduce electricity costs, your best bet would be to purchase a grid-tie inverter and get it connected to your household power supply. 

No need to purchase batteries as it will just pull the extra power from Eskom and the grid-tie will then offset your complete household power usage, not just the pool. 

I found this very interesting, but could not really think of a good use until this thread came along:

https://www.geewiz.co.za/inverters/105986-solis-07kw-mini-4g-single-tracker.html

However, for about the same price, you can probably get a used microcare 3000VA grid-tied.

https://www.sustainable.co.za/collections/grid-tied-inverters/products/solis-mini-4g-1-0kw-single-tracker-grid-tie-inverter  

If you get a larger grid-tie you could also offset some of the power your geyser is using, I would suggest getting something bigger though so you can add extra panels on later to offset more of your household usage. 

The 3.6kw Solis would probably be a good option IMO, is dual MPPY and you need a start up voltage of more than 90V so you would probably want to get more than 2 PV panels. 

https://www.sustainable.co.za/collections/grid-tied-inverters/products/solis-mini-5g-3-6kw-single-tracker-grid-tie-inverter

 

6 minutes ago, P1000 said:

I found this very interesting, but could not really think of a good use until this thread came along:

https://www.geewiz.co.za/inverters/105986-solis-07kw-mini-4g-single-tracker.html

However, for about the same price, you can probably get a used microcare 3000VA grid-tied.

Only thing to watch out with the Microcare's is that they do not have a "0" grid feedback control as standard and it is something that needs to be purchased separately @ a cost of +- R3k 

Another thing to consider - a 750W pool pump refers to the motor output. Small single phase squirrel cage motors are pretty inefficient (as far as squirrel cages go), so most of them are around 1100W electrical. Of course, the actual usage will depend on the loading of the motor (but the apparent power will always be quite close to 1100VA). See the plate on the motor for the input power spec.

Edited December 1, 20214 yr by P1000

If you use a soft starter with a PV systems ... which can be setup to reduce inrush currents ? 

I am finding I get a lot of queries for pumps to run off solar ... but people indicate it is an expensive method.

Booster pumps attached to JOJO tanks is another common enquiry.

 

 

23 hours ago, P1000 said:

I found this very interesting, but could not really think of a good use until this thread came along:

https://www.geewiz.co.za/inverters/105986-solis-07kw-mini-4g-single-tracker.html

However, for about the same price, you can probably get a used microcare 3000VA grid-tied.

That is a good one but to small for the pump.  The 3.3Kw is a good one.  The reason simple you can add as more cash gets available safe more add more.  the small one you are stuck very fast and will not drive the pump in full.  I have a 3K3 with two PV inputs +/- R6K  when I bought mine. Standing on a shelve. But it is worth starting at 3K3.

I originally got this small one for some reason it did not like my surroundings the 3K works very well although it is not working at this moment

 

29 minutes ago, isetech said:

If you use a soft starter with a PV systems ... which can be setup to reduce inrush currents ? 

I am finding I get a lot of queries for pumps to run off solar ... but people indicate it is an expensive method.

Booster pumps attached to JOJO tanks is another common enquiry.

 

 

All depends on your size motor PV panels but on a day like today in Cape Town no soft starter will help. I have a few pumps on solar.

My first inverter was a 1.5KW off grid paid R600 tested it with no MPPT and only a good charger.
That I upgraded the for R1200 pure sine wave 3Kw unit.  That handled my two 1.2Kwatt pumps.
Then by simply staggering the timers I ran the pumps and worked well.
I know have a .450 water pump, 450W swimming pool pump and a 200W fountain pump.  works no problem in running it from the 3Kwatt inverter. I changed my filters and works super (16 000l pool)
Then I have another 100Wtt unit. pumps 110mm flat out water 24/7

Pumps work easy on solar a nice 3Kw of grid will d the trick.

The only problem I found is that when one have only solar and no Eskom then when the Kw from solar is low the pumps stops and start sops and start.

For that I did a simple modification.  It is very simple a small voltage detection cct with a delay of 5 minutes or what ever.  That stopped the stop and start stuff.

For my bigger pump 400l per minute 6Kwh 3 phase a soft starter is recommended.  As a matter of fact a soft starter is recommended when going above 1.5KW ALL DEPENDING ON THE SIZE OF INVERTER AND THE AMOUNT OF UV.

The far best with this configuration is grid tied. You draw from the grid when starting and supplement it with solar.  When running full one only use solar.  When the pumps are off then you feed back.

 

You can never ever lose with grid tie. All other systems are difficult of which pumps are natural enemies of batteries.

 

 

46 minutes ago, isetech said:

If you use a soft starter with a PV systems ... which can be setup to reduce inrush currents ? 

I am finding I get a lot of queries for pumps to run off solar ... but people indicate it is an expensive method.

Booster pumps attached to JOJO tanks is another common enquiry.

 

 

I don't think you can get a soft starter for single phase motors? They are also not price-competitive with VSDs from china. So the better solution IMO would be to attach a 3 phase pump to a VSD, then you can soft-start and also run the pump at lower speeds, like the Badu eco pump.

https://www.sustainable.co.za/products/badu-eco-touch-variable-speed-ac-pump?_pos=4&_sid=36dd61d38&_ss=r

Wouldnt this be a typical flood lead acid battery type application?  ... big amp/hr and set DOD high to create as many cycles as possible ... it just seems there is no many saving solution ... you either use lithium and loose the power or flood lead acid and loose the cycles ? 

 

 

2 minutes ago, isetech said:

Wouldnt this be a typical flood lead acid battery type application?  ... big amp/hr and set DOD high to create as many cycles as possible ... it just seems there is no many saving solution ... you either use lithium and loose the power or flood lead acid and loose the cycles ? 

 

 

From the original post, it seems that the pump is currently connected to grid. So this is an ideal case for grid-tied. There should be no need to complicate it with batteries.

1 minute ago, P1000 said:

I don't think you can get a soft starter for single phase motors? They are also not price-competitive with VSDs from china. So the better solution IMO would be to attach a 3 phase pump to a VSD, then you can soft-start and also run the pump at lower speeds, like the Badu eco pump.

https://www.sustainable.co.za/products/badu-eco-touch-variable-speed-ac-pump?_pos=4&_sid=36dd61d38&_ss=r

Even better ... install a small 3 phase motor (much cheaper and way more powerful) ... use a single phase to 3 phase VSD ... all round win win ... most good motors come with winding to suit. 

I do these type of conversion for people who close down factories and move into the garage at home ... and no longer have 3 phase power ... we just fit a plug top with a piece of cabtyre ... run a 4 core screened cable from the VSD to the motor and change the bridge pieces on the motor to suit ... even better on lathes ...because you can fit a pot and control the speed. 

1 hour ago, isetech said:

If you use a soft starter with a PV systems ... which can be setup to reduce inrush currents ? 

I am finding I get a lot of queries for pumps to run off solar ... but people indicate it is an expensive method.

Booster pumps attached to JOJO tanks is another common enquiry.

 

 

Surely a soft start is only required if you want to run from an Off-grid solar inverter? 

If you are using a grid-tie it will just pull the power the inverter can't supply from Eskom.

47 minutes ago, isetech said:

Even better ... install a small 3 phase motor (much cheaper and way more powerful) ... use a single phase to 3 phase VSD ... all round win win ... most good motors come with winding to suit. 

I do these type of conversion for people who close down factories and move into the garage at home ... and no longer have 3 phase power ... we just fit a plug top with a piece of cabtyre ... run a 4 core screened cable from the VSD to the motor and change the bridge pieces on the motor to suit ... even better on lathes ...because you can fit a pot and control the speed. 

I have a Veichi 3 Phase VSD running my 1.5kw pressure booster pump, works like a charm. 

Thank you for all the replies.

My main goal was to reduce energy consumption. Seeing the replies, it looks like I should just get a 5Kw Sunsynk inverter with a couple of panels, tied to the grid. I will then run a swimming pool pump from that. Later on, I will add battery storage and supplement with grid where necessary. Much later, add another 5Kw Sunsynk and more panels.

On 2021/11/30 at 1:34 PM, McGuywer said:

Trying to save on electricity costs, so I was wondering about this.

I have a 750kw 5Amp swimming pool pump. Can I get a 100AH battery, 1000kw Inverter and a 2x 540 Solar Panels to run my swimming pool pump from solar?

The idea is that the battery will just act when the pump is starting up, I will set the pump on a timer and only start the pump when their is full sunshine?

 

Thoughts?

750kW pool pump - how big is your pool? I think you mean 0.750kW or 750 watts.
As others have suggested, probably better to get:

• grid-tie inverter (no battery) (eg Solis)
• hybrid inverter (allows for battery for critical loads later)
• microinverter - attaches to the panel (eg Hoymiles)

The electricity generated can be used for the whole house - not just the pool.

Note: You can register to feed excess into the grid or install a CT coil/DTU to prevent feedback.

22 hours ago, McGuywer said:

Thank you for all the replies.

My main goal was to reduce energy consumption. Seeing the replies, it looks like I should just get a 5Kw Sunsynk inverter with a couple of panels, tied to the grid. I will then run a swimming pool pump from that. Later on, I will add battery storage and supplement with grid where necessary. Much later, add another 5Kw Sunsynk and more panels.

Sounds like a good plan @McGuywer, only thing that you need to be aware of is the Max. AC Current (A) that can flow through the 5kw is 30A or about 7.2kw.

If you try to push more than that through the inverter it will trip out.

In my experience it is quite easy to reach that limit but your experience may obviously vary depending on your household power usage.     

My suggestion would be to get an 8kw if possible, the max on the 8kw is about 12kw

58 minutes ago, Sc00bs said:

Sounds like a good plan @McGuywer, only thing that you need to be aware of is the Max. AC Current (A) that can flow through the 5kw is 30A or about 7.2kw.

If you try to push more than that through the inverter it will trip out.

In my experience it is quite easy to reach that limit but your experience may obviously vary depending on your household power usage.     

My suggestion would be to get an 8kw if possible, the max on the 8kw is about 12kw

Nice to know, thank you! I am certainly now leaning towards the 8kw.