Got a test in the yard running where it is on a full battery (the truck's) on a cloudy/sunny day hardly half an amp though
First, my controller has some sort of index error where if I set it to 14.4 for cease-charging it goes to 14.8. 14.8 lets it go to 15.2 and now I have it at 14.0 and it is sitting at 14.4. OK, I can live with that, once I know what's what.
Next, the main screen actual voltage showing is say 14.4 but my meter says 14.5v I can live with that too. Still need some time with this to learn if the voltages you set are nominal and then it uses the temp compensated version or what.
Main thing is that it seems to sit at the cease-charging voltage, so that is also the float voltage maybe. It says it should drop in voltage once it gets there but nothing happened. I am hoping it does mean this is also the float voltage so it stays at my intended Vabs till dark. Need to use this controller in real life for a few days to be sure how it behaves.
The main display shows all bars full and the incoming arrow is black and flashing on and off, which is consistent with it being in float stage, full battery.
---Turned on the truck's lights and voltage dropped fast to 11.8, the incoming arrow changed to not flashing but showing moving black toward the battery icon which means it is charging and the bars dropped to show only about half full. So that all works.
Lights off, bars filling up, voltage rising into the 12s, so we'll see if it can get back to 14.4 (my setting is 14.0 to get that) with the poor solar conditions today.
The amps read-out shows various small amperages with the sky changing a lot and the battery is full anyway. At least it does show some amps, so that works too.
If it were for storage float, I would just set that voltage to whatever float voltage is desired, like 13.4 or whatever.
This test is not going to show if it is Series with amps tapering at Vabs, because the sky is cloudy and not enough amps to tell anything much, and the battery is not down far enough to show that anyway.
However if it were a Shunt on-off type, I would expect to have seen voltage running up and down the scale like my old shunt controller did it once it reached the high set point, and here the voltage is just staying there.