Our lithium bank is almost 9yrs old and we have never had a disconnect event. Like mentioned, a properly designed system will never disconnect outside of preventing a catastrophic failure like an internal cell going bad or a charging source going rouge. The whole bank disconnect should be considered a last effort to save the system, and not a routine event when the batteries are full.
Instead, either the charging sources should be set to shut themselves down appropriately, or the BMS should control a charging bus or the charging source itself and shut only that down. If you have an internally regulated alternator without any control of its charging and its regulator is set higher than necessary, then either the BMS should be able to cut its field, or the alternator should be connected to the start battery and a programmable DC-DC charger used.
Same for the opposite direction with loads, where inverters, reefer/freezers, and similar things that can be programmed to shut themselves off before the BMS needs to, and installing low voltage disconnects to other equipment (or DC panel).
This is where one needs to be careful with lithium drop-ins. Few if any have the above abilities, so more care must be made with design in other parts of the system to compensate. If you have these batteries in parallel, once one shuts down, the problem escalates on the others and a quick chain reaction leaves you with a dark boat. There are many reports of just this experience with them, and I would consider that a safety issue.
Mark
