Solar System Switches

Pete4049
Pete4049 Registered Users Posts: 4
Should I install a switch in the cable leading from my battery bank to the inverter.  What is the switch protecting?  The cable or the inverter or both?  Should there be a switch in the cable between the charge controller & the battery bank?  Do I need both switches?  Thanks, Pete
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Comments

  • 706jim
    706jim Solar Expert Posts: 519 ✭✭✭✭
    Or a high capacity circuit breaker. There's nothing quite like the surprise of a high amperage short circuit and you have no way of disconnecting it.

    Think "Fire".
    Island cottage solar system with appriximately 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing due south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter which has performed flawlessly since 1994. Outback Flexmax 80 MPPT charge controller four 467A-h AGM batteries. Insignia 11.5 cubic foot electric fridge 1/4hp GSW piston pump. My 31st year.
  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    edited May 2018 #3
    Installing DC rated circuit breakers in both positions, sized appropriately to protect the conductors feeding the inverter /battery, will not only provide a convenient service disconnect but also protect the conductors in the event of a short circuit. Batteries can supply enormous amounts of current which should never be underestimated, a fused disconnect, or fuse plus disconnect could bu used but must be DC rated for the appropriate voltage / current, but cost wise breakers tend to be the more economical in the long run as a blown fuse needs replacing, whereas a breaker would require resetting. The purpose of overcurrent protection is to protect the conductors not the device fed by the conductors.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.