The APS IQ4 Smart Charge Controller offers automatic charging control for APS power converters, providing longer and safer use of your systems battery. The IQ4 Controller allows the APS Power Converter to operate as a 3 stage “smart charger.” This gives the end user the benefit of bulk, absorption and float stage charging, increasing the charging capacity of the APS Power Converter and decreasing charge times insuring proper and safe battery charging and minimizing and over charging. This “smart technology” monitors the battery levels at all times. Please note that the APS90 is only a two stage unit and the APS 100 is not compatible with the IQ4 module. If the APS voltage remains in the long term stage for more than seven days, the IQ4 will automatically deliver a boost charge for a predetermined period of time then automatically return to the normal float stage.