Control System Power

[Al Skierkiewicz]

To all teams...
I have a suggestion that may help if your robot controllers keep cutting out during competition due to low battery. (Are you monitoring battery voltage during competition by changing the mode at the operator interface?) The power supply for the robot controller should be taken as close to the battery terminals as is possible. As most teams use both the six-way and twelve-way breaker panels, the robot controller should take it's power from the breaker closest to the +12 terminal on the breaker panel closest to the battery. This point has the lowest series resistance and therefore the lowest voltage drop under high current conditions. (V=I*R) Teams should also try to reduce to a minimum the length of the #6 wire between the battery and battery connector, between the connector and the breaker, and between the breaker and the breaker panel. For example if you have a total of 4 feet of #6 between the battery and the first breaker panel, the resistance is about .032 ohms. (.0004 ohms/ft x 8 ft=.032 ohms, remember total wire to and from battery) At 200 amps you would drop 6.4 volts. (.032 x 200=6.4) Obviously cutting that 4' to 2' would cut your loss by half and keep the robot controller at the required 8 volt minimum.
Is 200 amps possible? You bet! The battery specs state 450 amp, short duration pulses are possible with this battery fully charged.
Hope this helps, Good Luck All