Solar panel diversion dillema

System · August 2008

Hi All,

I just installed a grundfos 6sqf well pump w/101 box,200 box,and 3-Evergreen Spruce line 195 watt panels. This system is amazing! My pump is set at 360 feet and I think I'm getting close 5 gpm with around 450 watts per 200 unit display.Now the bad news! It fills up my 3000 gallon tank so quickly that the panels set idle half the time. My current off grid power system is the Outback Everthing. FX inverter /charger,AC panel,DC panel,and MX60 charge controller. I have 10-Evergreen 110 watt panels and 8 Trojan 6 volt batteries to complete my 48 volt system. I need to find an economical and effective way to divert the well pump panels to battery charging when water tank is full. My 110 panels are about 21 open volts and my 195 panel are about 32
open volts. By the way, My power system was professionally installed and I installed the pumping system. I'm a enhanced beginner at best. thanks,offgrid

mike95490 · August 2008

Re: Solar panel diversion dillema

> 101 box, 200 box
> 200 unit display

What are these ?

To charge 48V batteries, you need about 60V, which is in-compatible with your 12V pump

BB. · August 2008

Re: Solar panel diversion dillema

What voltage are the well pump panels setup for? (how many panels are in series, how many parallel strings?)

-Bill

Windsun · August 2008

Re: Solar panel diversion dillema

Since your panels are so different between the two systems, the only really practical solution might be to buy a separate MPPT controller just fo the pump panels and run that via a switch to the battery bank.

crewzer · August 2008

Re: Solar panel diversion dillema

My current off grid power system is the Outback Everthing. FX inverter /charger,AC panel,DC panel,and MX60 charge controller. I have 10-Evergreen 110 watt panels and 8 Trojan 6 volt batteries to complete my 48 volt system… My 110 panels are about 21 open volts…

This sounds to me like the array is configured 5 (modules in series per string) x 2 (series strings in parallel) to create a “60 V” nominal array (~86 Vmp STC, ~107.5 Voc STC). Please confirm. This array configuration should work very nicely indeed with your “48 V” system. As a practical matter, the array probably operates at about 76 V or so at midday with the controller in bulk (MPPT) mode.

I just installed a grundfos 6sqf well pump w/101 box,200 box,and 3-Evergreen Spruce line 195 watt panels. This system is amazing! My pump is set at 360 feet and I think I'm getting close 5 gpm with around 450 watts per 200 unit display.

Now the bad news! It fills up my 3000 gallon tank so quickly that the panels set idle half the time… I need to find an economical and effective way to divert the well pump panels to battery charging when water tank is full. … my 195 panel are about 32 open volts.

Ref: http://www.evergreensolar.com/upload/195W_Product_Datasheets/S195_US_010408.pdf
Pump and controller info: http://store.solar-electric.com/grsoposuwapu.html

I suspect the three E-195’s are wired in series to configure this array rated at 81.3 Vmp STC and 98.7 Voc STC. Please confirm. The typical operational Vmp will be ~72 V.

You could use a float switch to “divert” the array of 195’s to operate in parallel with the E-110 array. The overall array voltage would operate at ~72 V in bulk charge mode, but overall PV power and charge current to the batteries in bulk stage would increase.

Note that if your batteries are already reaching float stage on a regular basis, then adding more PV won’t achieve much... the system will just reach float stage a bit sooner. However, if you’re looking to add additional loads, then I think the concept should work.

HTH,
Jim Goodnight
“crewzer”
Eastern Regional Sales Manager
OutBack Power Systems

System2 · August 2008

Re: Solar panel diversion dillema

Hello,

Thanks for all the great responses!
To answer a few questions: The 101 SQ Flex switch box makes it possible to switch off the voltage supply to the pump and connect to a back-up generator.
The CU 200 SQFlex control unit offers:system monitoring on the basis of sensor signals,system control on the basis of sensor signals,monitoring of pump operation and alarm indication, and also allows the use of a float switch (which I have). Also Crewser was correct on the panels: the 110's are wired 5 in series X 2 strings. The 3-195's are wired in series and go direct to the 101 box. The pump itself (6 SQ Flex) has the capability on running on 30-300 volts dc or 1X90-240 volts ac . It has its own built in computer and MPPT. I hope this helps a bit more. By the way Crewser if your idea still works, what would I need to buy to hook up to float switch to divert power to the MX60.

Thanks again folks,
offgridkid

System2 · August 2008

Re: Solar panel diversion dillema

Hi,

I'm not only a novice solar guy , I'm not much of keyboarder either. Just a added note. Sorry about your name misspelling Crewzer. I forgot to clarify my power system power level. I live in Northern Arizona, so in the summer we get lots of heat and cloudy monsoon weather. I'am constantly having to run a generator to supplement my power system. The added PV from my pumping system would be a great help to my power system. In the winter we get lots of clear and cold days and the system works much better. Anyway, I guess the more information the better.

Thanks to All,

offgridkid

mike95490 · August 2008

Re: Solar panel diversion dillema

offgridkid wrote: »

Hi,

I'm not only a novice solar guy , I'm not much of keyboarder either. Just a added note. Sorry about your name misspelling Crewzer. I forgot to clarify my power system power level. I live in Northern Arizona, so in the summer we get lots of heat and cloudy monsoon weather. I'am constantly having to run a generator to supplement my power system. The added PV from my pumping system would be a great help to my power system. In the winter we get lots of clear and cold days and the system works much better. Anyway, I guess the more information the better.

Thanks to All,

offgridkid

'cause you asked, and I'm a sucker. You will need a water level float switch, mounted near the top of your tank. When the tank fills up, you want it to trigger a relay so the panels divert power to a new charge controller, wired in parallel to your 48V battery bank.

What is loading your battery bank so much that you are not getting full charge? Are you running a swamp cooler? Air Conditioning ?
What are the loads the 48V bank is powering? Do you have any system monitoring to track what your panels produce, and what the inverter is supplying ? A +80A array ought to be doing something !

Maybe consider permanently moving the 3 panels and a 48V controller to your large array, and buy a single new panel for the pump. Might be simpler than water level floats, relays, and all that.

Try running your generator in the morning for a couple hours to bulk the batteries, and let the solar top it off.
(what is your 48V charger capable of outputting to the batteries from the genset, 10A, 20A ?)
Kill your loads for a day to get a full charge on your batteries, or risk destroying them from chronic undercharge.

Mike

Solar panel diversion dillema

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