These chargers are also called ''taper chargers'' because charging present minimizes little by little, as the battery will get charged. Normally, a totally-charged transportable battery backup system will power a regular CPAP device for anywhere from 8 to 24 hours. Having said that, This is often only a common estimate, https://www.reddit.com/user/AutoBatteryCharger/comments/1fuyoy8/trusted_industrial_tools_supplier_in_india/