Using Second battery to Charge Tanks

[wilsonmw04]

Greetings,

After reading a "what do you do in between matches" tread, it seems like it is common practice for some teams to charge their air tanks with one battery, then swap out a fresh battery before heading to the field.


I have seen one post on the Q&A on this topic:

Question: Can the air tanks on the robot be pre-charged with air before entering the arena? If so can they be charged with a seperate power source than the battery used in the match?

Reply: Review R69 and Blue Box in the manual.

Here is R69 and the Blue Box:

<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.

If an alternative compressor is used, the team may be required to provide documentation to show compliance with the performance specifications.
The only difference between an on- and off-board compressor is that the off-board compressor is physically removed from the ROBOT. The intent of this rule is to permit teams to take advantage of the weight savings associated with keeping the compressor off-board. However, using the compressor off-board of the ROBOT does NOT permit non-compliance with any other applicable rules.
The compressor may be mounted on the ROBOT, or it may be left off the ROBOT and used to pre-charge compressed air in the storage tanks prior to bringing the ROBOT onto the FIELD.

So, is it legal?
I read this as one compressor and one battery mounted on your robot. Therefore, it would be illegal to change the battery after the tanks have been charged.

Am I reading the rule correctly?