Well, the title pretty much says it all. I have a few identical 12v DC adapters, and I would like 24 volts for a device I would like to try out (says it needs 24 volts for charging). By the way, this is my first post, I know im going to spend hours reading all these posts. I am just starting out and have many plans on the projects and Ideas I want to build.
If they are regulated adaptors, series-yes, parallel- NO (the linear regulators inside will fight each other over the line due to slight differences between them during manufacturing).
If they are unregluated, series yes, parallel-yes.
Make sure they all have the same current capacity rating, either way. Differences in current rating due to tolerance will make the one with the highest capacity work slightly harder than the others but it should be okay.