controllers 101

hi i have a small system 20a 12v/24v controller w/ 1- 12volt battery . my question is, if I put a 120watt 24volt panel will need to add another 12v battery or will the controller charge the 12 volt battery or will it over charge do to the 24 volt panel?


  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: controllers 101

    What do you have for a controller? Make and model #?
    If the controller is set (adjusted) to charge a 12 volt battery, or if it can automatically detect battery voltage and self adjust to either a 12 or 24 volt battery, then yes, it will use the amps available from the panel to charge the 12 volt battery. However, unless the controller is of the MPPT type, at least half the panel output in watts will be wasted.
    The following controller would be excellent for you're present system and would harvest all the power you're panel can provide, but if you're thinking of expanding, pick one of the bigger ones. Of course even with the very best of controllers there are always some small losses and inefficiencies.
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