My team is using a full sized CIM with a 100:1 gear reduction. We start to climb and then when the robot gets off the ground out volts drop from 12.6 -> 10.1 and the motor locks up. The volts then go back up and then the volts instantly drop again and again. We cant figure out the issue any help or suggestions would be appreciated. Thanks!!!

What diameter drum are you using?

It sounds more like the motor controller is current limiting or the motor breaker is tripping. What size breaker are you using? The Vex 10:1 reductions are not rated for the CIM. But when those break it will be a little more permanent.

What size breaker are you using in the PDP? We had a similar issue at our first event. Upon inspection, it turns out while we were wiring the bot during build, someone installed our climber with a 20 amp breaker instead of the 40 amp breaker that was mean to be there.

More information about your setup would help.

Information about motor size and reduction is useless without pulley diameter. Look into the JVN calculator. That said, a CIM with 100:1 is higher than usual, and is probably strong enough. Depends on pulley diameter though.

As others have said, it’s probably the snap action breakers. Listen for clicking noises from your PDP, and see if your CIM or the wires leading to your CIM is getting warm.

We are currently hooked up to a 30 amp breaker. I will try switching it to a 40 amp breaker and idk the drum size. We do not have a pulley the motor is directly connected to the hex shaft.

If your drum diameter is anywhere under 6" (a pretty massive drum), you shouldn’t be having any problems with breakers tripping unless you have serious mechanical problems.
How does your rope wrap around the drum when climbing? Is it jumping off to the side, or otherwise getting wedged somewhere? Are there any grinding noises while climbing?

Thank you all we fixed the issue the breaker was tripping and we added a plate to stop it from getting wedged

How did they do that? The 20A breakers are usually smaller than the 40A ones.