How long will a 12v lead battery run a laptop?

Update
A friend offered as a christmas present a solar kit, SO I have this one coming to me
https://www.northerntool.com/shop/tools/product_200773337_200773337

Maybe, I should make a new thread…but I’d like suggestions for a battery and a cigarette lighter type plug that will work with this set up. I just bought a cigarette lighter plug for my computer to charge it off of DC.

hmm…maybe I’ll start a IMHO thread