[Al Skierkiewicz]

A sharpie is a good thing to have on you at all times. Mark the suspect batteries as "practice only!" Mark your new ones with the date you opened the box and put them on the charger. Mark the side or the top, never the bottom. You will wear off important info if you mark the bottom.

Sammy,
Remove all the snap action breakers and then see what happens. The only thing running should be the Crio and the wireless access and the camera if you have one. If you have a camera, pull the plug on the bottom. If the battery doesn't discharge, then add two breakers that feed your drive train and see what happens when you drive. If the battery stays up, add two more breakers and repeat. Typical electrical problems are frayed connections at the Crio power input connector or the power output connectors on the PD. The same is true for power feeding the sidecars and Crio interface cards. Check all the wiring on the PD as this is another area where a frayed wire will contact and adjacent lead.
Another common problem is through the camera which has a power supply common to the camera case. Plug the camera in last if you have one. When you are telling us the battery is falling to 8-9 volts is that reading on the dashboard/Classmate or with an actual voltmeter across the battery terminals? It is not uncommon for there to be a failed 50 amp battery connector on the robot side that could be dropping the voltage. A bent contact, a poor crimp, a damaged terminal on the PD all could give the effect of low voltage to the robot.