Ah! This is incorrect in several ways (the article that the converter came from will be worth reading because it describes basically the same setup.) He wanted the 800l as well as the power converter, but the power converter he had is both too low current (the 800l needs 2amps max and the converter is only 600ma) and the wrong voltage. The 800l maximum voltage is 4.2V and giving it 5V may damage it. It expects to connect to a 18650 type LIPO battery (there is a fritzing part for the 18650s) or a 2A capable boost/buck converter adjusted to 4V output to power the 800l. It is unclear to me if the 800L I/O pins are 5v tolerant or if you want to use a 3.3V nano to avoid level translation (I didn’t read the data sheet for the 880l that far.) I suspect the power bar module in the image isn’t in fact the USB converter that I posted, but rather an 18650 battery charger / 5V output converter module which needs to be able to provide more than 2A (because the Nano is going to draw current as well) and a step down circuit to get the 4V@2A for the 800l. It looks to me that the Power bank module in the image is not a Friting part (probably because they couldn’t find a part) but rather a note in the sketch with wires connected to it, and thus doesn’t reflect what the actual part is supposed to be unless there is a part number somewhere not shown. Ah! I think I see what is going on. If the switch is dpdt then it looks like the battery (which should be an 18650 rather than the shown AA) connects directly to the 800l (which is dangerous without a battery protection circuit! As LIPO cells will explode or catch fire if shorted!) to supply the needed 3.7 to 4.2V to the 800L and the converter wants to be a step up conversion module which coverts the 18650 3.7 to 4.2V to 5V regulated for the Nano. As long as the 800l inputs are 5v tolerant (you would need to check the 800l data sheet to see if they are or not, or if they expect 3.3V inputs) this should work fine. I’ll have a look and see if I have a Fritzing part for a 18650 to 5V power converter or not. I may have made one in the past (that should also give you a part number for the part you need.) There are a bunch of modules on ebay and others that take a 18650 battery and convert it to 5V regulated to power USB, I don’t remember if there is a Fritzing part though.
Peter