Solar Pump's quit after week or so...

SkyMo

New Member
I suspect I will get back "you get what you pay for" but seems like what I have should work....

I have a bank of 10 100A/hour AGM batters wired in 5 parallel banks for 24V output. I have a couple charge controllers keeping them feed from bunch of panels.

My static water level is about 40 feet down and I place the pump at the 90 ft level. It's another 60 feet from the well to the solar shed so I about 150ft of 8 gauge cable. I bought a 4" Solar Submersible Water Pump- 24 V - Direct DC - SPDC - SPDC24V/I-40-3-0.4-1 from pump supermarket and that lasted about a week. Got another one that one also lasted about a week. They run great and suddenly just stop.

I want to run my pump when it's not sunny out so that's why I run off battery.

Should go to a 48v system? Higher quality like RPS or Grundfos solve my problems?
 

snoobler

Solar Honey Badger
150' of 8awg @ 24V and 17A has a voltage drop of...

3.2V

It's only seeing 20.8V, meaning, more amps...

Suspect it doesn't like low voltage, and it's getting burned up.
 

SkyMo

New Member
They are designed to connect directly to solar panels. I would think they could handle the low voltage. But maybe not...
 

Steve777

New Member
Your well system is similar to mine. I am using an RPS pump/controller. Running 320W of PVs at nominal 24v. Well is 120' deep, pump sits at ~90' down. Two 12v 120Ah AGM batts. My panels and batts are right at the well so no long runs of wire, except down the well. I let the RPS pump controller manage charging the batts, which is not the most efficient (simple PWM vs MMPT), but it has been adequate so I did not upgrade it. I also have a long (150') horizontal run of the water line from the top of the well to the cistern.

I am surprised by the size of your battery bank (or perhaps it for for more than pumping water). My 120AH bank handles running the pump overnight no problem.

Hardly any problems in 3+ years of use (a bit of a flakey low well sensor which I will replace when I pull the pump to change the rotor mechanism).

Also, my well is fairly low flow (rated at 0.4g/min), and I have the pump turned down so that it pumps at that rate or a bit slower.

You don't mention how much water you are pumping in a typical day, but it seems like it must be a large amount. That may be another significant difference between our systems.
 
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