Mecanum power draw issue when weighted down

[DHP7320]

We have a mecanum drive configured with AM 6 inch mecanum wheels, AM CIMple Box 4.67:1 gearboxes, 1 CIM per gearbox, 1 encoder per wheel wired directly to a JAG, 1 JAG per wheel using the CAN bus and in speed mode with PID control. The system was running great when it weighed 40 lbs (just the chassis, drive train and electronics). When we loaded it to approximately 100 lbs, JAGs began browning out randomly and we don’t think we can reliably get through a 2 minute match. We are consuming so much power that batteries barely make it 3 minutes. After much CD research, disassembling & testing motors and a mess of other things, we’re looking at going to a different gearbox with closer to an 11:1 gear ratio because the CIMs supposedly draw less current at higher RPMs. Is that worth the time, effort and money? Just to be clear, even loaded, the bot drives well. It just consumes so much power that JAGs start failing after 1-3 minutes. We were thrilled with our first mecanum drive at week 2. Now (after weighing it down) we are a bit panicy to say the least. Thanks in advance.