Looking for help with solar well in remote African village

elirentzelirentz Registered Users Posts: 2
Being new to the forum I guess I should introduce myself. My name is Matt and I recently graduated with my BS in EE but have little experience with solar systems. To make a long story short my mom does mission work in Tanzania some of which includes working with a team that drills wells for remote villages. They have recently decided to switch to solar power pumps but no one involved has much experience with electrical work. The first system they installed is a Lorentz 1800 controller and a matching centrifugal pump (not sure which model) with no batteries. It worked ok for a while but has recently quit working, which is where I come in. I've offered to try my best to help figure out the problem as well as help with future projects.

Here's what I know (which isn't much considering the info is from a French electrician translated through Swahili): The panels are making power, there are lights on on the controller but no power out of the controller. The system gradually pumped less and less each day until it eventually stopped.

I've already noticed a couple of things that need to be fixed regardless. Here's a couple of pics:

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The most obvious thing I see that needs fixing is the way the pump power cable is being hung from the panel mounting brackets and stress relief is a zip tie to who know's what. I'm planning on at least trying to get all the wire into conduit for obvious reliability and safety issues as this is located at the village school. I'm planning to do all the obvious tests for power and continuity etc. Another problem is there are a few small trees that appear to be in the way during certain times of day.

Do any of you have any suggestions for either troubleshooting this system or for designing the future ones? Is Lorentz a respected name in the industry or are there better choices on the market?

Comments

  • BB.BB. Super Moderators, Administrators Posts: 31,085 admin
    Re: Looking for help with solar well in remote African village

    The decreasing output sounds like a poor electrical connection somewhere... Look for browning at wire/terminal connections. Also, look very closely the solar panels. Corrosion internal to the panel, delamination/browning from a high resistance point (looking through the glass cover), check the terminal box for water intrusion (if not sealed, also make sure drip loops run water away from the box instead of into the box, drilling a small "weep hole" in the lowest corner of each electrical box will allow condensation to be expelled).

    I would suggest getting a DC current clamp type meter (Here is one from Sears in the US that is ~$60 which is "good enough" for debugging systems... Also includes AC current, and normal DMM type functions--cheap enough you can bring a couple with you to the site).

    With solar panels, you can find about 80% of the bad panels by measuring Voc (perhaps with a small load resistor) and Isc (short the panel with a current meter).

    If you have parallel solar panel strings, you can measure the current from each (with a DC Current Clamp Meter), or try taking one string out of service at a time (find string that is not supplying current).

    In your case--it sounds like a controller/pump problem--Here are some manual links (PDF if you can download/open them):

    Product Manual
    789KB
    Installation Manual 274KB(smaller)
    Motor
    The LORENTZ submersible motor, type EC
    1200-C is a 2 pole synchronous brushless DC
    motor. Slide ring bearing and ceramic trust
    bearings are water lubricated.
    The motor raw earth magnets are hermetically
    sealed in stainless steel and encapsulated in
    synthetic resin.
    The motor is pressure compensated and there
    are no practical depth limitations for
    submergence.
    No electronics are inside the motor and the
    entire motor is water filled.
    Data:
    Voltage: 3 X 100V electronically commutated
    Power: 1,6kW / 2,2HP
    Efficiency: 92% max
    Controller

    The controller for these pumps (if I have the correct manuals) is more or less a VFD (variable frequency drive or "inverter").

    If the input voltage/current from the solar array meets the requirements of the VFD, then it should run. If the motor has seized (sand/dirt in well, run dry, etc.), then the controller may try to start and then give up if the pump is not rotating.

    For a different type of pump, we did have an Austrian Mfg. post some information in this thread:

    New Solar Water Pump System for Rural and Remote Areas

    I hope this helps.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Looking for help with solar well in remote African village

    Welcome to the forum.

    I know some of the members here are familiar with the Lorentz pumps and have a positive opinion of them. I believe they are more prevalent in Europe than NA.

    Unfortunately at this point you're shooting in the dark. The panels may produce Voc but not Vmp (meaning they show Voltage but are unable to supply enough current to run the pump). The controller could have failed. The pump could be clogged or failed. Without being able to disconnect and diagnose the individual components, there's no way to tell what you're up against.

    At the very least you'll need to have the panel specifications and array configuration. Then you can test the panels individually for short-circuit current and see if there's any problem there. After that it gets trickier.
  • KeithWHareKeithWHare Solar Expert Posts: 140 ✭✭✭
    Re: Looking for help with solar well in remote African village

    Looking at the installation manual for which Bill posted the link, the controller supports an optional low water probe, and an optional float switch.

    If the probe and/or switch is installed, it is possible that one or the other has failed. If they are not installed, there are supposed to be jumper wires. If a jumper wire were not screwed down tightly, the pump would not run.

    Keith
  • elirentzelirentz Registered Users Posts: 2
    Re: Looking for help with solar well in remote African village

    Thanks guys for the helpful info. Unfortunately, like one of you said, it is like shooting in the dark at this point. I just want to try to cover as many bases as possible when trying to prepare for the trip as getting supplies and tools can be difficult. I'd also like to learn as much as possible so that I can teach someone that lives there how to maintain the system and troubleshoot problems since its obviously not easy for me to get over there.

    I do have a Fluke 374 AC/DC clamp meter as well as another multi-meter. I plan on printing a copy of the manual as well for specs etc. Another problem is they haven't gotten their holding tank put up yet so the system ran continuously while the panels made enough power to run the pump and as you can see in the picture there is a ton of waste.

    Do you guys agree that the way the wire is installed now could be either part of the problem now or an inevitable problem in the future?

    I appreciate all your help.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Looking for help with solar well in remote African village

    It's certainly possible it could be a wiring problem. Sloppy wiring can easily become broken wiring, or even a bad/intermittent connection. Knock out one panel in a string of panels and you could lose the whole string. Then you may not have enough power to run the pump.

    Running it constantly probably wasn't a good idea either, as the well may have been pulled down too low. That's when you can get sediment clogging the intake or the pump itself.
  • solarixsolarix Solar Expert Posts: 713 ✭✭
    Re: Looking for help with solar well in remote African village

    Look into a type of pump call a rope pump. They are the rage all through developing countries because (with the exception of the plastic stoppers) they can be made and serviced on site..
    I've played with them myself and is very simple, efficient and inexpensive - and can be motorized. Can't be a deep well though and can't meet sanitary standards in the U.S. so you've never heard of them here. Just google "rope pump"
  • cruiser guycruiser guy Solar Expert Posts: 87 ✭✭✭✭
    Re: Looking for help with solar well in remote African village

    Are you SURE there is no power from the controller?

    We had issues here in Sierra Leone with our solar pump which supplies our compound that was working fine until the end of the dry season in March. At that point we got a team of visitors, added an extra family full time and a larger storage tank, all of which ended up in our pumping the well dry! The controller did not indicate a dry well but the pump was pushing a lot of air so you tell me what else it could be?

    Depending on the time of year I'd suggest possibly you're pumping the well dry.

    On wells for the villages we use a hand pump, usually an India Mk III deep well hand pump. Easier, cheaper and locals can understand and fix it with a few much cheaper tools.
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