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Solar Borehole Pump/conversion

Posted: Thu Nov 03, 2016 12:24 pm
by Mars
Has anyone gone this route? I have a single phase 1500w borehole pump installed in my borehole and am looking at a solar solution. First prize would be to use the existing pump which would mean pv panels, Inverter and battery bank although the pump only needs to run during the day. So I am looking at a current draw of 7Amps to be safe. And probably a 2000W pure sine wave inverter.

Any advice/experiences would be greatly appreciated? Chrisf?

Re: Solar Borehole Pump/conversion

Posted: Thu Nov 03, 2016 1:12 pm
by ChrisF
Marnus have you looked at the range of solar pumps that Grundfoss supplies to the farmers ?

Nice thing with these is that the school fees have been paid and you KNOW it will work, and will last for years.

but sit down before checking the price ....


Converting DC to drive an AC pump ... nope. Nothing is impossible, but this conversion is just not practical.


PS - you are looking at more than 100A on the DC side !!

Re: Solar Borehole Pump/conversion

Posted: Thu Nov 03, 2016 2:43 pm
by Mars
Thanks Chris. Well I have had a look at some of the Solar Pumps and I am going to have to pump water for many many years before I make up the capital outlay in potential savings. The "professional" ones are EXPENSIVE.

The idea of "free water" is just very alluring!

Re: Solar Borehole Pump/conversion

Posted: Thu Nov 03, 2016 2:59 pm
by ChrisF
Marnus how much water do you want to pump, and how high ? A 1500W pump is a monster pump ...


My neighbour is looking into a small PV powered pump to water his garden from his rain water tank. I might have some more info on this type of application shortly.

Re: Solar Borehole Pump/conversion

Posted: Thu Nov 03, 2016 3:01 pm
by JamesC
I supply Lorentz pumps, if you are interested.

Re: Solar Borehole Pump/conversion

Posted: Thu Nov 03, 2016 6:50 pm
by Rigger
Install a Grundfoss pump with solar panel and forget about it. If you only want to pump during the day, no need for batteries and inverter the pump has its own control box

Re: Solar Borehole Pump/conversion

Posted: Thu Nov 03, 2016 9:57 pm
by Johan Kriel
Grundfos SQF's can run off 220V AC also. Same wires, just not simultaneously. Many believe the Lorenz is in the same clas, but is a bit cheaper .

I have 3 Grundfos SQF solar pumps. Very little issues. Only one needed to be repaired so far in the last 7 years. .

Re: Solar Borehole Pump/conversion

Posted: Fri Nov 04, 2016 6:49 am
by Mars
ChrisF wrote:Marnus how much water do you want to pump, and how high ? A 1500W pump is a monster pump ...


My neighbour is looking into a small PV powered pump to water his garden from his rain water tank. I might have some more info on this type of application shortly.
Therein lies the rub Chris. I need a head of 85m. No small solar pumps there. When looking at the yield I need per day at that depth I would need to go for the 800w Grundfos (probably even the top model) or equivalent. I need about 5000 to 6000 lt. per day. The graphs of those pumps drop very quickly the deeper you go. And those graphs are under perfect conditions of sunlight and pv angle. Fortunately, looking at the direction my house is facing it seems as if it was built for solar panels.

Thank you guys for the input.

Re: Solar Borehole Pump/conversion

Posted: Fri Nov 04, 2016 7:06 am
by ChrisF
Ouch !!

Best to track down the Grundfos guys in your area.

OR speak to James about the Lorentz range.

These suppliers deal with these figures daily and will quickly help you

Re: Solar Borehole Pump/conversion

Posted: Mon Nov 07, 2016 7:12 pm
by Koppelaar
Mars wrote:Therein lies the rub Chris. I need a head of 85m. No small solar pumps there. When looking at the yield I need per day at that depth I would need to go for the 800w Grundfos (probably even the top model) or equivalent. I need about 5000 to 6000 lt. per day. The graphs of those pumps drop very quickly the deeper you go. And those graphs are under perfect conditions of sunlight and pv angle. Fortunately, looking at the direction my house is facing it seems as if it was built for solar panels.

Thank you guys for the input.
How dit you calculate the 85m head required?

The nice thing with the Grundfos SQL range are that they are both AC and DC. On the Dc supply you just keep on adding solar panels ( there is a limit though) untill you get the delivery required. My SQL is installed 100m deep with water level at 35m and pumps 1500m far to a tank that sits 12m high. And it delivers about 2500 l/hr under normal conditions. When i need to pump at night or when raining I just start a 5kW el cheapo gennie and it pumps 3000 l/hr. The drawback is the cost. Paid about R25k for pump and control box, R8k for cable and then about R10k for solar panels. And then the pipe, etc.

Re: Solar Borehole Pump/conversion

Posted: Tue Nov 08, 2016 8:52 pm
by Johan Kriel
That control box of Grundfos is actually a contactor for when you connect a generator to it, not really required, you can just disconnect it from the solar and plug it to the generator. The pump is now about R18000.00.

The head must be the total height difference plus pipe friction.

.

Re: Solar Borehole Pump/conversion

Posted: Wed Nov 09, 2016 6:53 am
by ChrisF
Johan Kriel wrote:That control box of Grundfos is actually a contactor for when you connect a generator to it, not really required, you can just disconnect it from the solar and plug it to the generator. The pump is now about R18000.00.

The head must be the total height difference plus pipe friction.

.
I have the Grundfoss pump at my pool.

I use a manual change over switch to switch between PV or Eskom. So the pump is on PV 99,9% of the time, but I can easily backwash after hours.