Battery Management Like a Pro Team

The fastest robot in the world is useless on a dead battery. Top teams run a battery program, treating batteries as a managed, numbered fleet rather than an anonymous pile. This is one of the highest-return, lowest-cost upgrades a team can make.

Know your battery. The standard FRC battery is a 12V sealed lead-acid pack, 17-18.2Ah, with nut-and-bolt terminals (rule R601). The widely used MK ES17-12 (12V, 18Ah; sold by REV as REV-19-2487 and by AndyMark) is a representative example. Each robot uses exactly one such battery, and a strong one is the difference between a robot that holds voltage and one that browns out.

Measure health, not just voltage. Resting voltage barely moves between a great battery and a tired one; what matters is internal resistance, which is what causes voltage sag under the hundreds of amps a robot pulls. Use a load tester such as the CTRE/AndyMark Battery Beak (am-0995), which mates directly to the SB-50 connector and applies an ~18A load to report state of charge, voltage, and internal resistance, and helps judge overall battery health. Tracking a battery's internal resistance over time is the documented way to decide when to retire it before it fails on the field.

Build the program:

1. Number every battery with a permanent label and a logged purchase date. Batteries age out with hard use.
2. Load-test on arrival and periodically. Record internal resistance over time; a rising trend predicts retirement before it fails on the field.
3. Rotate evenly. Cycle through your batteries so they wear uniformly, rather than hammering one and leaving others idle.
4. Charge correctly. Use an FRC-legal charger at the manufacturer-specified rate and keep battery vents unobstructed. Fast/overcharging shortens life.
5. Handle with care. Never lift a battery by its wires; doing so can crack internal connections and raise resistance. Any battery that is dropped is marked faulty until re-tested.
6. Match-day discipline. Only 'Good' load-tested batteries go on the robot. Keep clearly-separated 'needs charge,' 'tested good,' and 'retired' staging areas in the pit.

Why it wins: eliminations are played late in the day on batteries that have been cycled many times. The team whose worst battery is still strong has a real, measurable advantage in voltage held under load, which translates directly to acceleration, mechanism speed, and brownout immunity when it matters most.