I have found topping off is great if you have a battery bank at 90% charge already.
In my case when my batteries run down to the 50% charge state I have to start charging right away and due to the time restriction I usually only get to the 90% charge in a three hour time frame. If I had solar then the batteries will eventually get to the 100% charge state.
The problem with going all the way down to the 50% charge state first your batteries have put them selves in danger. In my case I start losing battery bank performance if I continually drain them down to the 50% charge state and then bring them back up to their 90% charge state if I don't do a full 100% charge state after 12 or more of these 50% to 90% charge state runs.
I guess crud builds up on the plates of the batteries that only a full charge will burn it off...
I don't think I have ever had a problem with a good full time trickle charge on the batteries if they were at least at the 90% charge state to start off with.
Guess all of this makes sense haha...
Roy Ken
