I've installed a 12V 80W solar panel plus controller and attached it to a 12V 105Ah leisure battery. At first it (appeared to?) work. The charge status on the solar charge controller was at max and it stayed that way even though I used power.
After a few months of no usage (but connected to the solar panel) I found the battery empty (the solar charge controller indicated overdischarge).
Recharging with an external charger brought the battery back up to 12.46 V, which I researched to be 85 % (I didn't measure before charging unfortunately), but the solar charge controller still only shows it at 25 % full (first LED lit as per image)
I can't figure out what this tells me - is the battery weak (it was new before the solar installation), did my solar set up damage it? Is the controller showing the wrong info?