I understand that at competitions only VEX chargers may be used for the VEX batteries for them to be legal, however are teams allowed to use other chargers when not at competitions (during building and testing), and still use those batteries at competitions? This may let teams increase the lifespan of batteries by not significantly overcharging them every time like the smart chargers do. In other words, would ever using a non vex charger for a battery deem that battery illegal for future use in competition?
R13e only talks about legal means for charging batteries, and in the past there have been Q&A response(s) deeming the use of non vex devices for discharging batteries (for the purpose of reconditioning) legal. Unlike just running a robot for an excessive long time, high tech devices can regulate the discharge rate and prevent damage from over discharging. Is it still correct that the use of devices for discharging vex batteries is legal?
Yes, this is legal. We can’t micromanage the use of chargers outside of events. That being said we urge teams to exercise extreme caution when using non VEX battery chargers. Safety is the number one priority!
Almost all off the shelf discharge devices include a charging setting. As such the use of these devices at events is not permitted. As for usage outside of events, please see above.