So if you have an offboard compressor for refilling air pressure between matches, is it necessary to have an onboard spike relay to provide power, or can power come from an external power source? The rules don’t seem to be very clear.
<R69> Compressed air for the pneumatic system on the ROBOT must be provided by one and only one compressor. This compressor may be either the compressor from the KOP, or an equivalent compressor that does not exceed any of the KOP compressor performance specifications (specifically: nominal 12v, 1.03 cfm flow rate, 120psi maximum working pressure). Compressed air shall not come from any other source. Off-board compressors must be controlled and powered by the ROBOT.
<R70> “Working” air pressure on the ROBOT must be no greater than 60psi. All working air must be provided through one primary Norgren adjustable pressure regulator.
D. If the compressor is not included on the ROBOT (under the provisions of Rule <R69>), the regulator and high-pressure gauge may be located on-board or off-board, provided all other pneumatic rules are satisfied. Note that if the regulator is kept off-board the ROBOT with the compressor, then only low-pressure (60psi or less) “working” air can be stored on the ROBOT.
<R73> The pressure vent plug valve must be connected to the pneumatic circuit such that, when manually operated, it will vent to the atmosphere to relieve all stored pressure. The valve must be placed on the ROBOT so that it is visible and easily accessible. If the compressor is not used on the ROBOT, then an additional vent valve must be obtained and connected to the high-pressure portion of the pneumatic circuit off board the ROBOT with the compressor (see Rule <R69>).
There is a few other references in the rules that you should look at. Essentially an off-board compressor is allowed to gather a weight reduction by placing the compressor and allowed parts off the robot. You can place the Spike feeding the compressor off-board as well but all power and control must come from the robot. Your installation will be inspected for this. All other pneumatic rules will still apply.