newbie need help for off grid project

dags333
dags333 Registered Users Posts: 2 ✭
in Off Grid Solar & Battery Systems #1
g,day guys . i have a 600w water pump under the house that supplies the farm house with water .that i want to take off grid .
i have 250w of solar panels (the fold out ones with 2 125w panels)
1000 watt inverter. a 12v deep cycle battery 165amh . and on the panels is a mptt controller. when i hook the inverter on to the battery only and plug the water pump in to the inverter and turn it on it runs great no problem. but when i connect the solar panel terminals to the battery with the inverter . (i have the pos of the inverter and the pos of the solar both hooked on the pos side of the battery's and the others on the other on the other side) and turn it on its ok for a few minutes then the red light comes on the inverter and starts to beep then it starts ringing so i turn it off. i cant work it out .(not that i now much haha) the only thing i can think of is that the mptt controller could be only 10 amps and to small i dont know .would this make any differents any help would be appreciated.its doing my head in .thanks for your time
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #2
    My guess is that it is indicating low voltage. 165 amp battery with a 700 watt load (600 watt + inverter inefficiencies) would be a load of 700/12=58 amp load.

    I'm actually surprised it would start the water pump! but a 165 amp, lead acid battery bank under a 58 amp load is really difficult. You may also see addition voltage drop due to under sized wiring.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • dags333
    dags333 Registered Users Posts: 2 ✭
    #3
    thanks photowhit .when i have it pluged in to the inverter and running from the battery only. it goes good . but the pump only primes to the house  for 7 to 8 seconds and only comes on every hour maybe 3 times for  for about 1 to 2 mins. (what its meant to do)  so when i set this system up of  the solar calculator i put it in so this pump would come on for 1 hour a day (might come on 25 times a day for 1 min or so i just calculated 1hr per day use) thanks for your time . 
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #4
    Was the pump running when the inverter started beeping?

    Were the solar panels connected to the controller before you connected to the battery, or did you connect the controller to the battery first, then connect the solar?

    How are the two panels connected to each other? Any chance they're in series (+ of one to - on the other?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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