Battery monitors are an essential, not a luxury if you rely on a house battery for your power supply. Whilst an ammeter supplies accurate information on current being drawn or charged at any particular time and voltmeters will indicate when the battery has been significantly discharged, they do not give an accurate indication of how much charge is in the battery. That is a function discribed in ampere-hours, for which a battery monitor that measures charge drawn or charged over time is needed. A battery monitor can be likened to a fuel gauge. It is a complete battery check instrument which helps you to check the charge status of your batteries very easily.
