Answered: [VEX U] Battery Extension

There are four batteries possible on a VEX-U robot:

The 7.2v battery connected to the Cortex.

An optional second 7.2v battery connected to the Power Expander.

The 9.0v “Backup Battery” which is also connected to the Cortex.

Finally, the additional battery for sensors and electronics which can either a third 7.2v battery or the 9.6v battery used in the old VEX joysticks.

Regarding each of these batteries, my questions pertains to creating a custom cable used as an extension and will be asked on a case-by-case basis.

Let’s assume that this cable is constructed well, is ONLY two extension wires and does not attempt to alter the power in any way (it’s just a cable used to allow the battery to be mounted further away from the actual device it powers).

A. Is it legal to use an extension between the 7.2v battery and the Cortex? I believe not, but I’m not sure considering the VEX-U electronics rules. Technically the only rules I see regarding what a sensor or electronic device can interface with is:

An extension cable most certainly does plug into the Cortex and does not “electrically interface with the VEX motors or motor controllers,” so is it legal?

B. What about the Power Expander? Unfortunately it is not the VEX microcontroller (thus violating clause A from above).

C. what about the 9.0v Backup Battery? In this case, VEX sells a 2-wire extension cable (meant for the motors, but it’ll work either way). Can this product be used with the 9.0v Backup Battery as an extension?

C2. What about a custom cable under the electronics rule?

D. Finally we come to the extra sensors and co-processing battery, it is my understanding that there are no limits on what this particular battery is plugged into under the electronics rule. As such, I believe any viable wire, that does or does not attempt to alter the voltage is allowed, with the restriction that it can ONLY power sensors and/or co-processors.

Either way, what is the legality of using an extension with this battery?

Thanks again Karthik, I know this one is a big long. -Cody

Please note that the following response is only applicable for VEX U.

This is legal.

This will be considered legal.

This is legal.

This is legal.

This is also legal.