I just got a power expander. I know nothing about it. It did not coming with any paper work on the backing of the package. From what I read you connect the in and outs or something. But how do you tell your program to program those motors? We are using Easy C. I know you need another battery to make it work, but that is all I know. Anytime I look up something people are just troubleshooting, but I need more than help than that.
Thank you in advance!
As far as extra programming goes, you don’t have to do anything. Use a cable extension to connect from the motor port in the cortex to an IN port on the power expander. You can plug the motor you want to control in the corresponding port in the OUT port.
It is possible to see the battery status of the expander battery just like you would with the Cortex. Use a standard cable extension to connect from the Status port on the Power expander to one of the Analog ports on the Cortex. Be sure to make your port analog on the Controller configuration.
This diagram should help, as well. https://vexforum.com/wiki/images/3/3c/Power_Expander.jpg
You have a picture of your guys setup? I am still confused… LOL… Sorry, just don’t understand the concept… I saw tons at the vex competition but since we didn’t have a power expander we failed to take pictures and/or notes 
Do I have to have something to link the power expander to the cortex?
Thank you sir. As I was typing your were posting
Another question: So when I am running from cortex to expander how do I link up? My in is a male four prong?
I think I have it. From the cortex to expander in you use the red/white/black extensions… Then from the out you use motor controllers like normal?
Yes. [10char]
Thanks for all your help, you have been a blessing or we would never have been able to get the expander hooked up… One more quick question… Ports 1 and 10… Can regular controller 29 fit into those ports? They seem smaller. Am I missing something?
Yes, these ports allow you to connect a two-wire motor directly to the cortex (without a motor controller).
All of this information (and much more) is on the VEX wiki.
Thank you jpearman!
Darn, beat me to posting the link. But I think I should add that it helps to check the wiki sometimes when setting up some things.
