that is even unreliable anymore for information. you have to add some senarios to make that true.
if you are camping often, say every weekend go ahead and float it at 13.6 which will maintain you at 100%. if your storing it for the off season (3 months or over) then ya drop it to about 70% and disconect power.
if you have a single stage converter and want to plug in then just turn off charging on the battery if you have a bluetooth one, if you don't have a shut off switch and confirms it shuts off power to the battery.
mine for example because I can customize the settings in the solar controler will charge on solar and then drop the float to any percentage I want to keep it up. I usaly do about 90% to 100% (13.4 to 13.6V) depending how long I am going to be sitting in the driveway 🤔
now having said all that, leaving it at 100% is only going to drop cycle life over time, by how much.. who knows but I think people make a bigger deal about it than it warents, just because in the data sheet for most prismartic cells it says do not "store longterm at 100%" then they go on to define long term storage as 3 months or more. so then you also have to understand cycle life. for most cells that is charge at 0.5C to 100% wait 20 min then discharge at 0.5C to 0% wait 20 min and repeat. they keep doing this untill the cell capacity drops to 80% of the original design capacity. so for example my cells ARE 4000 cycles. that doesnt mean they are dead but at that point my 304Ah battery becomes a 242.3AH battery and who know how long it will go after that point. its kinda like that for a lot of tech like led bulbs, there rated in howurs to 80% of the original brightness but will stoo go on a long time after that.
now if we look at the cycle life test we all see a trend to list cycle life at 80% DOD. so charge to 90% discharge to 10% or some other combanation, but I suspect that would be the most common. so the new version of my cells lists 4000 cycles at 100% DOD, 8000 cycles at 80% DOD and somthing crazy at 50% DOD (hint there is no new version of my cells just a update in the different cycle life tests.) so one thing you can infer is the more shallow the cycle, the greator the life. when I am camping I normaly cycle just over 10% DOD (will have to see how much power the new camper takes next weekend) but I am also not cycling at 0.5C. in fact the old camper could charge at 0.18C at max, (the new one technicaly could hit 0.29C) but that creates less internal heat which also can increase cycle life so taken all the conditions on how I use my battery am I going to worry about floating at 100% (13.6V) when I am in campign season, not in the leaset. now if I had a 100AH battery and that was it thoes numbers would be a 0.3C depth of discharge, but I could charge well over 0.5C and discharge higher also. so in that case I would probably float at 90% and limit my charging to 0.5C.
now take in to concideration that AH to AH there is no battery as cheep at LiFePO4, so where I used to have four 6V 200AH batteries at 800 to 1000 bucks, you can now have two 100AH LiFePO4 batteries for about 400 bucks. so if you always replaced your lead acid every 5 to 8 years as long as you get that your saving money, and chaces are your going to go longer.
I just realized I am going down a rabbit hole and rambling on about stuff most people won't care about so I'll summ it up
your float voltage/level can change with the situation of how many batteries you have, what size they are, how big your charger is, how rapidly you discharge, your personal feelings, and how old you are. they all come into play 😉
