I have my geyser connected to Aux, set to only supply if more than 3 KW is available. It works perfectly when on Solar, but if there is little or no solar power, and we have load shedding, it tries to supply the geyser from the battery. If other power is consumed by essential circuits, it overloads, goes off for a couple of minutes, then 'recovers' and powers only essential circuits. How do I set it to not power aux from the battery?