Could anyone please recommend a solar borehole pump that fits the following:
- Reliable & low maintenance
- Low flow rate
- 50m hole, 35m full, an additional 50m or so uphill to the tank (1km away)
- For the Karoo, high iron & sediment content
I have bought pumps from this company:
No problem with transactions.
It’s the most uncomplicated set-up, as some of their small range has a built-in MPPT.
Just pick a pump with the voltage that suits your panel array Vmpp.
So it’s two wires from the panels to the pump, nothing else. The pump starts when the sun shines and stops when it doesn’t.
Do they work?
Yes.
It is remarkable how much head can be reached for so little power; obviously, there isn’t a lot of flow.
I’d get a 20m higher head than I thought I needed.
I got something like 400l daily with an 80m head and a 200W’ ish pump on 2 X 240W panels.
Are they reliable?
No, I don’t think so. They come with a spare rubber impeller thing. So that part obviously wears out.
I couldn’t grumble about construction. Decent stainless steel was used.
I got about a year out of the one I installed. Then lightning got it. But that could happen to the best pump.
So I don’t really know reliability-wise.
Alternatively, I would use a standard 220Vac borehole pump, but then you’re into the cost of an inverter and associated risks of theft if you’re remote.
So it depends on the application, really. The pump range from these guys is cheap and cheerful and very simple to set up.
If I was where I could keep an eye on things and I was making 220Vac anyway, I’d get a more powerful 220Vac pump over this type.
But you could probably get 2 or 3 of these pumps for the price of that set-up.
And as I say, two panels on top of a tall unclimbable pole and the pump + Mppt down a hole means it is less attractive to thieves than equipment at ground level.
I’ve only heard good things about the Grundfos SQFlex range from people that have them installed on their farms:
https://product-selection.grundfos.com/za/products/sqflex?tab=explore
The range is quite wide, but the ones you’re probably after are the 3" helical rotor models. They run off 30-300V DC or 90-240V AC, so you can wire them directly to your panels and when the sun is shining they will pump water. Dry running protection is built in. It is rated for a sand content of 50g/kl.
Here’s the pump curve for the SQF 0.6-2, which I reckon is the one you should be looking at:
They are not cheap though.
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Thank you , yes they are pricey guys I see!