How do I calculate what 80 RF is in MJ?

Solution 1:

Quarries run on Minecraft Joules, or MJ.

RF converts to MJ at a rate of 10:1, so 80RF is 8 MJ. Also, you don't need a tesseract to convert RF to MJ, you just need an energy conduit that is connected to a MJ consuming machine.

As for how many dynamos you need to power a quarry, quarries take up to 100MJ per tick (MJ/t), but will run perfectly fine on 25MJ/t.

To produce 100MJ/t, you will need 13 dynamos, which will be capable of producing a total of 104MJ/t (1040RF/t). They'll auto-throttle to produce only as much as is requested, so one will likely only run at 4MJ/t (40RF/t).