12V battery is now 10.5V but still producing a lot of power
Assumptions:  By matching 12V and 180Ah I find this SPG12-660W 12V180Ah
Your estimates of power draw on the laptop charger may be too high as that would only be used when the screen is on maximum brightness and the battery is charging at maximum current.
Your measurements are insufficient to measure State of Charge (SoC) or capacity. (Ah), remaining life (mo.) or % of new Capacity.
Look below to match up when you get better power measurements.
Concerns

you don't have OVP (over voltage protection)if charger goes to 15V vs 14.4Vmax  @ 25'C.  The spec is given in per cell so you multiply by 6 cells.

Cycle use
2.40V(-3.5mV/℃/cell)
Float use
2.27V(-3.5mV/℃/cell)


charge battery voltage should be well above 12V at sunset so your load may be greater than I expect or you have a weak cell from overcharge fatigue.  New,  the fully charged battery should be able to produce 34W/cell x6=204W for 10 h.

you need more  accurate data in a spreadsheet using a current shunt and any cheap DMM and more accurate data for P vs time.

if you charge 50W for 3 h or 150Wh with 100% (not) efficiency that would be 7% of new capacity of 180Wh*12V=2160Wh, so there may be 1 bad cell.



Capacity declines normall from a 10h dischrage rate. But for this battery the table says 34.4W/cell for 10h=2064Wh