[dcbrown]

The EX18/ES18 battery specification lists a maximum rating of 230A for 5 seconds. Various estimates of a 120A load based upon the the battery specification chart and different derating values yields between 20-40 seconds of rated battery life. Real life experience may differ, but the these are the rated values from the specification.

So on the practical side, pushing the battery beyond 120A for all but short brief periods will mean the 'bot will die before the round is over. Running two 120A main breakers would seem to indicate the design only wants the robot to run a few seconds before completely draining the battery AND it would allow the battery to be run outside of its specifications.

Running the battery anywhere up around the maximum rated value of 200A+ for any time at all is flirting will damaging the battery at least or causing some safety issue like melting or worse. Also, the number of discharge/charge cycles the battery can go through is highly dependent upon the rate and depth of discharge. Draining capacity at high loads can severely shorten the lifetime of the battery. Some data on AGM/GEL cells indicates as few as 10s of cycles under these extreme circumstances.

So even if you wanted to run multiple 120A breakers, there is no practical reason to do so -- the battery would at best drain very quickly and not last through the competition. All such a design would be doing is causing a potential risk to the robot as well as others.

Of course there have been rumors of changing the battery for this upcoming season, so there may be a whole different set of issues in two weeks to discover.

On the practical side, the motors when geared down seldom fully stall but instead start spinning the wheels even with grippy treads.

Bud