Hi Yvo,

I see you are in waddinxveen. When you need service: I know SVL is a good company. They can certainly help you. (not affiliated).

About te battery topping system: most likely the two floaters of those cells are stuck or leaking and filled with water. Pretty straight forward: get them out and you'll see how this works.

Don't know about the discharge indicator, but when you use it very little as you say, just charge it once every two weeks and you'll be fine.

GL.