Going to a bigger bank won't help either.
How much time do you spend away from
shore power charging?
What is your average AH per day usage?
No matter your bank size, in the end your charge sources must put back in a bit more than you take out. Sooner you get back to 100% the longer your bank will last.
What a bigger bank does is help you avoid going down below 50% too often.
Very few alt / reg setups output a proper charge profile for a deep cycle bank out of the box.
Many don't even let you adjust the voltage setpoints or Absorb hold time, need to switch to an external
regulator like Balmat MC-614, or fit a "battery to battery" DCDC
charger like Sterling or ProMariner.
Same with old or
cheap solar controllers.
80w won't do much if you use a lot of AH per day, really only good for the low amp "long tail"
You need to get the bank to 80-85% in the early morning first using dino-juice. Or get a lot more solar.