Hi all looking for your thoughts on increasing the State of Charge threshold on my lithium batteries. I have just upgraded my boat 12 volt system with 3 x 200 AH Smart Lithium batteries and a Lynx Smart BMS to replace my old 1180 AH AGM batteries. I also have a Muliplus II, Cerbo, and two MPPT controllers with 1400 watts of solar. I also have a generator installed and no shore power. I found with the new install, when not on the boat, I consume about 8% of the batteries overnight (mostly fridges). During the day the solar panels supply the load in float and a small amount of charge. This continues for 5-6 days until the discharge eventually reaches the default State of Charge threshold of 70% and a new charging cycle commences with the batteries recharged from the panels in bulk in around three to four hours. While this is fine and exactly how the system is intended to work we have been having a very wet winter with many cloudy days in a row with minimal solar output. I have considered increasing the State of Charge threshold to 85% so that I start a new charging cycle every 2-3 days instead of every 5-6 or so days. This increases the likelihood of getting on the boat with a full charge and minimises the impact of poor weather. This will also result in more frequent, shallower discharge/charge cycles (which is obviously what we are used to with our older AGM batteries). I am aware of the different charging characteristics for lithium but unfortunately can’t find any good literature to suggest whether this change is a good or bad idea - hence my question to the group. Any thoughts or similar experiences fine tuning State of Charge greatly appreciated.
Thanks
Sarah