Our motorhome stays connected to the mains so the batteries are always charged. This causes the batteries to go through the distilled water a little quicker than if they were left off. So I have to monitor and charge both batteries every three months. It's very easy with this system. All you need is a system mounted on a battery or batteries and a pump (see my other review). The other end of the pump is attached to the irrigation system in a jug of distilled water. Several pumps and batteries are filled with water. My batteries are fairly affordable, but if the RV owner has batteries that are difficult to access, this system is a godsend. Installation was a little difficult, but if you take your time, it wasn't that difficult. Highly recommended!