Quote:
Originally Posted by JesseK
Do not ever set your battery on concrete.
I don't understand the chemistry/physics behind it, nor do I ever intend to delve into the science of why it happens but something about rebarb, concrete and long half-life radiation  drains your battery if it's in close proximity to concrete. I saw it happen repeatedly at the VA State Fair with our robot and rather than trying to understand why I'll just accept the fact that it happens for now.
What we saw was that the charger would say our battery was fully charged. We'd then transfer the battery to the robot and place it on the field. At the start of the match, the bot would move extremely slowly, and the OI would indicated ~7V on the battery. About 15 seconds into the match, the voltage would go UP and the robot would act normally. Who knows why ? What I do know is, we do not place batteries on concrete any more and we haven't seen the problem since.
If you thought your batteries were charged and then you get these results, perhaps this is why. |
I'm highly skeptical of this. In olden times before plastic cases for batteries, this was true as slightly porous casing materials could would become moist on a damp concrete floor and let some current flow, draining the battery, but those days are a rather long way behind us. There simply isn't any possible way for batteries to self-discharge faster than normal just because they're on the floor.
If your robot was moving slowly for the first 15 seconds of a match, I think it's much much more likely that there was a programming error in your autonomous mode that was causing some of your motors to fight each other and put a large load on the battery. Autonomous mode IS 15 seconds long, after all.