How many amps is the circuit breaker/fuse on that outlet? You need to compute how many amps you draw at peak power usage. If it's over the rating you'll be venturing to the breaker box a lot or buying fuses by the case.
I may be wrong but I think you would use the formula Watts = volts x amps (this is used for single phase motors) I'm sure others will know if it's correct or not...

edit Actually that won't work because it's a DC equation. Easiest thing is to add up the amperage ratings on all the devices and see if it's close to the breaker/fuse max rating...