This is for pensioner friends - they have 8x100aH batteries of which 4 are very soft. It runs on an AXpert 5kva inverter with 4 x 320watt panels. They have a forget it and leave it attitude and the system has been installed for 3 years with the original batteries. They only found there was a problem when the system went to bypass when they plugged in the 3000watt kettle. Their budget is 10-12k for replacement batteries (which can be recon).
I was thinking to remove the dud batteries and wiring just the good 4 batteries up in the meanwhile.
I was thinking of a solution with 4 x 200aH batteries