um, 100% of the rating is usable to get the rated life. if you use 80 to 90% your going to get more, and to be frank either us or the battery will age out before the extra cycle life is ever hit 🤣
so say it is rated for 3000 cycles (that's on the low end now days) but that is 8.2 years with a full cycle every day. if we only use 80% of the capacity you could in theory get 5-6000 cycles but at 5500 that's 15 years. its going to be interesting to find out when they will start aging out vs cycling out for the average rv'er. I don't know anyone who does a 100% cycle at 0.5C charge and discharge with only 30 min rests at the top and bottom. (that's EVE's cycle life testing protocol)
now having said that, I only use 10 to 20% of my capacity, but that is because I set my battery up for reserve capacity so if my solar craps the bed I don't have to stop my trip early. and with the pricing of 100AH batteries now there is no reason someone can't upgrade there reserve a little bit and do a shallower daily draw but have the extra capacity incase of an emergency, weather it is running the furnace for a cold weekend or charging up the battery of the unit parked next to you. I have actually done this a few times, the guys camping next to me were running a darn noisy generator to charge their trolling motor battery. I told them to bring it to me when they come off the water and I'll make sure it is charge for them as long as they promise to not run the genny.