It's always good to provide as much info as possible when asking this type of question. Ideally, a link to the EDF unit in question is best, that way folks can look for the information relevant to your question. But you have most of the pieces we need.

27A at 280 watts means that the EDF is designed to work with a 3 Cell battery (a link to the EDF would tell us if it's capable of handling higher voltage - Watts = Volts x Amps so 280 watts / 27 amps = 10.3Volts and a 3 cell nominal voltage is 11.1V).

You typically want some additional head room on your ESC, say 20 - 30%. So if the max amps is 27A, then you will want an ESC minimally in the 35A range. Note that it is always better to have more head room and its also worth considering that you might use more powerful EDFs in the future so think about a 60A ESC which later on can handle a 70mm EDF on 4 cells.

In terms of battery, it should be able to handle 27A draw comfortably. It is common to get higher C rating batteries for use with EDFs, for example 40 - 45C. In terms of battery size, again, you need to be able to deliver 27A comfortably and the battery needs to (a) fit in the plane and (b) not be too heavy for your plane. Some info on the plane would help. An rough estimate of how many amps you can get from your battery can be made by multiplying the capacity of the battery in mAh by the C-rating, divided by 1000 (to convert the mA to A).

For example, a 2200 mAh battery with a 30C continuous rating can, theoretically, deliver 2200 x 30 / 1000 = 66 amps. Note that this is theoretical and you should provide considerable headroom here if you can by selecting a higher C battery. There is no set standard as to how manufacturers assign C-ratings to batteries. Also note that if you go with a smaller battery, you should check that the C-rating and battery size will support your current needs.

DamoRC

Edit:

@Bricks - did you mean 2

**S**, 3

**S**, 4

**S**...?

Another edit- sorry, misread 8 presume you meant C as in "Cell"