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Off-Grid Solar’s Killer App

46 points by tmfi 5y ago

kumarvvr 5y ago
This is a fantastic application for micro scale solar systems. The interesting part is for such very low powered apps, the pumped water itself is a battery, in the sense that the functional requirement can be fulfilled inspite of intermittent power is to pump water to the surface and use it when required.
ed25519FUUU 5y ago
It's good to see more companies investing in DC well and water pumps. DC pumps are an absolute must for off grid irrigation. Nearly all current well pumps are impossible to use off grid with solar panels without a HUGE battery and inverter because they're high voltage (or worse 3 phase) and use an ENORMOUS amount of amps when the pump first starts up. To give you an idea, a wimpy 1 HP 220v well pump can draw 35 amps for the first 5 or 10 seconds when it starts up. That would require TWO Tesla power walls to support.
- Andys 5y ago
  I run such an AC pump, and I had good success adding a VFD controller instead of buying a new DC pump. It still runs off AC but internally runs off DC and back to AC again. It now has soft start and variable speed control, and draws about 30% less power than before.
  - 20after4 5y ago
    Is this possible with a single phase pump or only 3 phase? All of the VFDs I've had experience with are only for 3 phase motors although they run from single phase AC input. The average well pump in the US isn't going to be 3 phase, however...
    - ed25519FUUU 5y ago
      I think all VFDs are 3-phase, but you can get a similar effect using an soft start, which is common in the RV world for starting a compressor/AC on battery power.
    - Andys 5y ago
      Mine's single phase, and it works with a single phase VFD.
tw04 5y ago
I wonder if they are tracking the underground aquifers? If he's extending his growing season and increasing his crop size without regard for the new found water source it just feels like there will be an even greater crisis down the road when the source eventually runs out.
- ncmncm 5y ago
  The article does touch on aquifer drawdown. It is a problem that needs continuous attention. Drip-feed irrigation helps, which uses less water but more power, and needs sensor networks and active electronic control, thus power again and sophistication, and tuning to local needs, thus more sophistication.
viciousvoxel 5y ago
This is awesome. I actually just set up a rain collection/solar irrigation system for my house and we are anything but off-grid. It all runs off of a 12v battery and a small solar panel. I think a similar program could be great for encouraging urban agriculture as well, while reducing water waste and energy consumption.
ncmncm 5y ago
We can just hope the places where these systems are used are still inhabitable in ten years. As temperatures rise, the ability to sweat off enough heat declines, even when there is enough extra water to drink. It is worst where humidity is also high, which anyway the desert areas of east central Africa do not suffer from, but Africa has plenty of high-heat/high-humidity habitat. If it becomes too hard for humans, I wonder what other animals will be able to do. What happens when chimpanzees can no longer live in the few remaining places they can now?

46 points by tmfi 5y ago

This is a fantastic application for micro scale solar systems. The interesting part is for such very low powered apps, the pumped water itself is a battery, in the sense that the functional requirement can be fulfilled inspite of intermittent power is to pump water to the surface and use it when required.

ed25519FUUU 5y ago

It's good to see more companies investing in DC well and water pumps. DC pumps are an absolute must for off grid irrigation. Nearly all current well pumps are impossible to use off grid with solar panels without a HUGE battery and inverter because they're high voltage (or worse 3 phase) and use an ENORMOUS amount of amps when the pump first starts up. To give you an idea, a wimpy 1 HP 220v well pump can draw 35 amps for the first 5 or 10 seconds when it starts up. That would require TWO Tesla power walls to support.

Andys 5y ago
I run such an AC pump, and I had good success adding a VFD controller instead of buying a new DC pump. It still runs off AC but internally runs off DC and back to AC again. It now has soft start and variable speed control, and draws about 30% less power than before.
- 20after4 5y ago
  Is this possible with a single phase pump or only 3 phase? All of the VFDs I've had experience with are only for 3 phase motors although they run from single phase AC input. The average well pump in the US isn't going to be 3 phase, however...
  - ed25519FUUU 5y ago
    I think all VFDs are 3-phase, but you can get a similar effect using an soft start, which is common in the RV world for starting a compressor/AC on battery power.
  - Andys 5y ago
    Mine's single phase, and it works with a single phase VFD.

tw04 5y ago

I wonder if they are tracking the underground aquifers? If he's extending his growing season and increasing his crop size without regard for the new found water source it just feels like there will be an even greater crisis down the road when the source eventually runs out.

ncmncm 5y ago
The article does touch on aquifer drawdown. It is a problem that needs continuous attention. Drip-feed irrigation helps, which uses less water but more power, and needs sensor networks and active electronic control, thus power again and sophistication, and tuning to local needs, thus more sophistication.

viciousvoxel 5y ago

This is awesome. I actually just set up a rain collection/solar irrigation system for my house and we are anything but off-grid. It all runs off of a 12v battery and a small solar panel. I think a similar program could be great for encouraging urban agriculture as well, while reducing water waste and energy consumption.

ncmncm 5y ago

We can just hope the places where these systems are used are still inhabitable in ten years. As temperatures rise, the ability to sweat off enough heat declines, even when there is enough extra water to drink. It is worst where humidity is also high, which anyway the desert areas of east central Africa do not suffer from, but Africa has plenty of high-heat/high-humidity habitat. If it becomes too hard for humans, I wonder what other animals will be able to do. What happens when chimpanzees can no longer live in the few remaining places they can now?