If you are using 12 volt batteries hooked in parallel, using this BatteryMinder 128CEC1, you will not want to have your camper in use, while using this device. As batteries are hooked in parallel with red clamp to positive and black clamp to negative, you will want to use the disconnect switch on your camper, while using this device. If you need to use your camper then you may not want to go with this option, in this case check out the OBD-12V
that works with the converter to restore and condition the batteries. Below is a wiring diagram that will show you how to hook up 12 volt batteries in parallel and using the 128CEC1. Hope this helps, if you have any other questions, feel free to ask.