Is a DC pump worth it? (Grundfos)

[rnorty]

I need to pump water out of my inground cistern, into my home. Low head (-20ft drop), but want 10+ GPM. Cold climate with a decent amount of rain and snow so I want to use a submersible pump so it's one less thing to freeze. Is there any justification to go the solar + AC from "house" (supplied by batteries/inverter) route, as opposed to just running a 240V circuit about 100ft from my battery room? I need to be able to run the pump when there is insufficient sunlight to run it on solar.

If it does make sense to got the AC/DC route, I spoke with RPS, but would rather buy better quality components. Grundfos seems to be respected, but there IO101 AC interface is designed to failover solar? Is that right? I would hope that I could find a power supply that could use solar, and then AC as a backup.

 

[Mattb4]

Not sure all what you are asking but if you have a PV/inverter/battery system that can provide AC to a pump it likely is the simplest route to go. It is not very practical to run DC long distances except at high DC voltages. Your inverter must be sized properly to start and run the pump.

The purpose of batteries would be to run your pump when there is insufficient solar. Batteries are storage.

 

[Madcodger]

I agree with @Mattb4 - just run an AC line out to the pump and call it a day, as that gives you the power you need when there's no sun. I can say that we're thrilled with our Grundfos SQ well pump (280-foot deep well). Here's a graph of its actual electric use so far this month, for a two-person household. Peak use is only 835 watts (virtually no surge with this pump) and under 2 kwh used in over a week, including one day where I know we did 4 loads of laundry, ran the dishwasher, etc.

 

[OzSolar]

The SQ Flex is an amazing pump with a stunning price tag that is hard to justify in many cases. If you already have AC power all you need is a regular SQ and last I checked it was around 1/3rd the cost.

I'd spend my time and money stacking back up pumps and energy sources. EG: If my main system went down, either from low sun or component failure, how am I going to still pump water? The SQ pump can be plugged directly into a very modest "suitcase" gas generator or Ecofow/Jackery.

edit to fix typos

 

[dopeassjackson]

Cictern mounted and low head. I would just stick a $100 cheap amazon submersible well pump in there.

If your worried about it leaving you with no water then put 2 in, still cheaper than even a big box store version.

 

[cn670]

I agree with @Mattb4 - just run an AC line out to the pump and call it a day, as that gives you the power you need when there's no sun. I can say that we're thrilled with our Grundfos SQ well pump (280-foot deep well). Here's a graph of its actual electric use so far this month, for a two-person household. Peak use is only 835 watts (virtually no surge with this pump) and under 2 kwh used in over a week, including one day where I know we did 4 loads of laundry, ran the dishwasher, etc.

View attachment 254732

Could you share the model of pump, and do you have pressure tank ?

 

[Madcodger]

Looks to be a 10 SQ05-160. Says 5.2 amps on the label.

I had them set me up with a spare when they installed it, and have it on a shelf in the mechanical room in case the original dies. I don't want to be without a water pump if both the SHTF that disrupts supply chains and a lightning strike occur at about the same time. And yes, I do use a pressure tank and recommend it. Pump comes on at 40 PSI, kicks off at 60. Pressure tank supplies water between those two. Works great!

 

[cn670]

Thank you for the info. I presently have a Goulds 115v 5gpm at 140feet, 4024 magnum inverter . It pulls 22 amp AC at start. Then 11 amp. It certainly does run the pump but I’d rather have a soft start pump.

 

[Madcodger]

Thank you for the info. I presently have a Goulds 115v 5gpm at 140feet, 4024 magnum inverter . It pulls 22 amp AC at start. Then 11 amp. It certainly does run the pump but I’d rather have a soft start pump.

I can honestly say that the Grundfos SQ pump is one of the best "appliance" purchases we've ever made. Why manufacturers don't build all pumps this way is beyond me.

 

[CMDRZOD]

Also have an SQ pump at my home, for my deep well. No inrush current, 4-500W running. Also one of my best purchases since going off grid.

 

[IAm_Not_Lost]

I can’t speak to your exact setup but we have a Grundfos DC solar pump in a 250ft well and it works great. But we still have to use an AC surface pump to go from the surface cistern to the pressure tank and the to the house like you normally would.

 

[wpns]

Is there a Grundfos residential pressure pump to draw water from my cistern and pressurize it to ~60PSI at up to maybe 5-10 GPM? I have a Goulds but the lights dim every time it kicks on…

 

[outboard1196]

Is there a Grundfos residential pressure pump to draw water from my cistern and pressurize it to ~60PSI at up to maybe 5-10 GPM? I have a Goulds but the lights dim every time it kicks on…

The sq pumps can be mounted horizontally and used as you want if you have the room.