Our distributor finished setting up a 120KW off-grid solar power station with our Koyosonic OPzV2500-2 tubular gel batteries 5 years ago in Mozambique. The solar power station has been in good operation condition. The engineers checked the batteries and it shows SOH is still 100%. Therefore there is no problem for our Koyosonic OPzV batteries to work for more than ten years. The fact tells us that OPzV tubular gel batteries are the best one in service life in lead batteries, especially iused n energy storage.