Hello team. One of my clients called me yesterday to notify me of a potential disaster on his offgrid victron Multiplus 24/3000/70-50 based solar system. the other components of the systems are a 250/70 Smart solar TR MPPT , 12* 310W solar panels and 10 by 10 by 12V,230AH gel batteries wired in series/parallel. the inverter room was smelling and gassing and on checking the system, THEY realised 4 batteries had popped up open , and the other 6 swollen and showing signs of a popping up too sooner rather than later. some adjacent batteries had actually got stuck to each other most probably due to heating , we had to apply considerable force to seperate them. no battery stand was on site , the batteries where stacked on top of each other in 2 rows of 5 seperated by two wooden blanks between top and bottom row.it is the space between these two wooden planks that had the most swelling. i replaced the entire battery bank with 6 brand new rolls surrette s12-220AE batterries. Please assist possible causes of such a failure and how it can be avoided in the future .