I want to connect two laptops batteries for an upcycle project. So not that the length of usability is doubled, but that the power, i.e. The wattage that the parts spend, doubles.
So if each of the batteries outputs 30 watts, I want to have 60 watts of power by connecting them together. How do I do that? Is it enough to combine minus and minus and plus and plus?
I'm afraid it's not that simple; In the batteries there's (usually) control / balance electronics that communicate with the laptop, which you can't easily synchronize. The only way along the way would be to double the capacity but the performance itself would remain the same, since the batteries would then only be controlled by electronics.
What you can do would be to build a portable charger from the batteries, that would also increase the performance:-)