First off, set the gamerule to false with the command:
/gamerule doDaylightCycle false
Then place down a bed and set the time to night or wait until it becomes night.
/time set 18000
OR
/time set night
Finally, right click the bed so you sleep in it and wait until you have slept and gone out of the bed.
Notice that it is still night, but you indeed have set the spawnpoint next to your bed.
If you set the gamerule to true, the bed works as intended.
I am not aware if this is a feature/bug fix in 1.8.3 and i hope to get information on this.