Why does one need an equalizer?
A battery equaliser is used when you when have two or more 12V batteries connected in series. It is used to keep the voltage of each battery the same. Over time, with each charging/discharging cycle, the battery voltage is will start to become unbalanced. Each battery will also have a different self-discharge rate.
Step 1:
Connect the two 12V Hubble S120 batteries in series with a suitable battery cable and connect the white cable to the positive terminal of the battery as a voltage reference for the equalizer.
Step 2:
Connect the positive and negative leads of the Hubble equalizer to their respective terminals on the Hubble batteries. NB: Do not reverse the polarity of the equalizer!
Step 3:
Connect the battery to the inverter with the correct polarity.