[adciv]

Here's what you're not taking into account. With a 20A charger in the system, you're not charging the battery at 20A. You're using the 20A charger to supply the base load of the robot. When the power demand is for greater than 20A, the battery picks up the load. This will discharge it slightly, and once the load has been reduced, it will recharge at a low rate. The only way you exceed the 5.5A rate is if you have started to drain the battery. This could also be solved by using a motorcycle battery in place of the standard FRC battery.

As to the voltage spikes, that's an engineering problem which can be solved a few different ways. One way would be making sure you don't use that kind of charger, another would be to increase the capacitance in the system to dampen the spikes. I'd like to know the load on those chargers when the spikes were recorded.