Hello together, for two years I have been developing a Mercedes Benz LF409 as a camper. last year I installed a solar system. I used the following components: – 3 x 100 Watt solar modules – this solar charging controller – this solar battery Only three consumers (LED lamps, radio, USB charging socket) are attached to the battery, which are rarely used. The battery almost always had a charge condition of 100% (except during the winter, since it had completely unloaded). I heard from the battery a quiet hissing and then noticed that the battery was probably running out. Next to the battery there was already a white mass (pictures of it are attached). When I examined the whole thing more closely, I noticed that under the lid squeezes out liquid (hissing), which runs down sideways (also of this images are attached). Since I am an absolute layman in this topic, I would be grateful if you could tell me now what the lie to and what I should do now. If I have forgotten important information, please point out.