Understanding the V5 Battery Li-Ion 1100mAh

V5 battery

V5 Chart

The V5 Robot Brain, Robot Battery, and Smart Motor all work together to improve performance, even when the battery charge is low. The V5 Robot Battery Li-Ion 1100mAh was designed to allow the motors to perform at their fullest potential. The battery has enough power to run ten V5 motors at full power continuously.

old battery

The old Nickel Metal hydride (NiMH) battery chemistry no longer meets the needs of today's high power mobile applications. Lithium Ion batteries are the future; however, when used in multi-cell packs they can have safety concerns and short life when used at high current levels. VEX chose a Lithium Iron battery chemistry LiFePO4 due to its safety and high current capacity. Additionally the new batteries have 4x the lifespan of NiMH batteries.

Continuous 15A Current Draw

The biggest change to the V5 Robot Battery Li-Ion 1100mAh is the higher 12.8v nominal voltage. The battery charges up to 14.6v and runs down to 10v. Due to the very steady output voltage of these batteries, the Robot Brain cannot determine remaining capacity using the typical method of measuring voltage and estimating capacity. Instead, the V5 battery pack has an intelligent battery management system that measures changes in electrical charge (coulombs) into and out of the battery during charge and discharge. From this data, the battery determines the actual amount of remaining power.

The intelligent battery management system also handles cell balancing and charging. Cell balancing is critical to maintaining battery pack performance over time, ensuring each cell in the pack is at the exact same voltage. Charge time is approximately 60 minutes.

Battery run-time depends on many factors including your robot design, your driving, and the number of motors used. Robots often get 30+ minutes of heavy drive time from a single charge. Competition teams should be able to use one Robot Battery for multiple matches without recharging. Remember that with V5, a low battery does not change the motor’s performance. The V5 Battery can output 20 amps continuously, providing enough power to run 10 motors at peak power output.

  V5 Robot Battery Li-Ion 1100mAh 7.2V Robot Battery for Cortex
Battery Chemistry Lithium Iron (LiFePO4) Nickel Metal Hydride (NiMH)
Approx Lifespan 2000 full recharge cycles 500 full recharge cycles
Nominal Voltage 12.8 Volts 7.2 V
Maximum Current 20 Amps 8 A (12 A with power expander)
Maximum Output Power 256 Watts 58 W (86 W with power expander)
# Motors at Peak Power 10 3 (5 with power expander)
Low Battery Performance Motors output 100% Power Motors output 51% Power
Capacity 14 Wh 20 Wh (32 Wh with power expander)
Weight 0.77lbs (350g) 0.47 lbs (213g)

For more information, help, and tips, check out the many resources at VEX Professional Development Plus