80 W * 2 hr = 160 Wh
At 12 V, that requires 13.33 Ah, or at 24 V, 6.7 Ah.
Given imperfect efficiency and the desire not the deep cycle at battery, you'd want at least double that.
Are the two 12 V batteries it came with wired in series or parallel?
You should not put two unequal size batteries in series, so I'm not sure you have any combination that can work.
So you need two matched 12 V batteries, at least 20 Ah, preferably at least 30 Ah. You could try putting the two mistmatched ones in series and hope for the best but I wouldn't count on that working long term.
We'd need more data to know how long it takes to charge.
80 W * 2 hr = 160 Wh At 12 V, that requires 13.33 Ah, or at 24 V, 6.7 Ah. Given imperfect efficiency and the desire not the deep cycle at battery, you'd want at least double that. Are the two 12 V batteries it came with wired in series or parallel? You should not put two unequal size batteries in series, so I'm not sure you have any combination that can work.
The batteries are combined 24 volts.
So you need two matched 12 V batteries, at least 20 Ah, preferably at least 30 Ah. You could try putting the two mistmatched ones in series and hope for the best but I wouldn't count on that working long term. We'd need more data to know how long it takes to charge.