Most deep-cycle batteries that RV'ers and boaters have are not maintenance free... thus requiring periodic checking and filling of fluid levels. This can often be a challenge as batteries are not always real accessible. The solution to this problem is to install a Quik-Fill kit, which allows you to pump water into all of the battery cells simultaneously. Each cell has a valve that shuts off the water flow to it's cell when it is full.
I do have some difficulty on my RV in checking and filling each cell as a couple of the cells are tucked under the step well, and are not readily accessible. This project actually consists of two parts.
The installation of new batteries and the installation of the Quik Fill kit. I figure that if I am going to the trouble to install the Quik-Fill kit, I might as well swap out my 5yr old batteries for new ones.
You can buy the components of the Quik-fill system separately so that you can build your system for the number of batteries you have. The major components are:
Note that the manufacturer does not recommend connecting more than 3 batteries to a system. However, if you have more batteries, simply connect them in 2 or 3 battery "pairs" and route each filler nozzle to a convenient point.
The kit will work on 6V or 12V batteries as long as the manifolds fit. The manifolds will not fit 4D and 8D batteries, which requires the "Pro-Fill" kit.