1. VEX Batteries

2. 3000 mAh “Big” Robot Battery
This battery lasts the longest, but it also takes the longest to charge. Use it in competitions.

3. 2000 mAh “Little” Robot Battery
This battery doesn’t last that long, but it charges quickly. Use it for practice.

4. Smart Charger (It shuts off automatically)

5. Smart Charger (It shuts off automatically)
Safe mode: Use this! This mode is designed to make batteries last longer.
Fast mode: Only for competitions. It can reduce battery life.
“No Light” – either the battery or the charger isn’t plugged in
“Charging” – battery charging
“Full” – battery is done charging

6. AAA (Joystick Battery) Charger
The charger can charge 8 AAA or 8 AA batteries but the joysticks only use 6 AA batteries.

7. Joystick Batteries Remove the VEXnet key
Unscrew the battery compartment
Remove the batteries and place on the charger 1 2 3

8. Red Lights = Dead Batteries (on the robot & the joystick)
Robot Light *
(red)
Main Battery = Dead (<5.5V) or CORTEX Off
(yellow)
Main Battery = Low (<6.5V)
(green)
Main Battery = Good
Solid
All Good: Both Joysticks connected
Solid + 1 Blink
All Good: Tx1 Joystick connected
Fast (red) [3]
Fault: Low Backup Battery (0V-8V)**
* The robot light on the joystick only works if the VEXnet light is green
** no backup battery is only indicated if the competition cable is connected
Joystick Light
Robot LED only works on Joystick when Linked.
No Backup Battery only indicated if competition cable is connected.
(red)
Joystick Battery = Dead (<5.5V) or CORTEX Off
(yellow)
Joystick Battery = Low (<6.5V)
(green)
Joystick Battery = Good
Fast
All Good: Both Joysticks connected
Solid
One Joystick in use
* no backup battery is only indicated if the competition cable is connected

9. Charge Batteries Every Night
&
Put the joystick batteries on the charger before you leave.
Put the big battery on the charger before you leave.
Put the little battery on the charger when you first arrive in the morning.

10. At Competitions After every match: Turn off the joystick*.
Put your old battery on the charger.
Put a fresh battery on the robot.
* If you forget to turn off the joystick your batteries won’t last for the whole competition.

11. One 9 V battery should last all day.
Backup Batteries
Plug into the Cortex Microcontroller.
Sometimes the robot loses power for a second.
The backup battery keeps the robot from restarting.
Only use for competitions.
One 9 V battery should last all day.

12. How to use a Multimeter Use a multimeter to measure battery voltage:
turn the dial to 20V (pictured)
black wire plugs into COM
red wire plugs into VΩMA
connect red to red and black to black

13. Before Attaching a Battery: Check the Battery Voltage
When batteries aren’t being used they test at higher voltages.
Over 8.0V: fully charged
Under 7.5V: dead battery
It is a good idea to check the battery even if the robot light isn’t red. The red light can come on a little slowly.

14. Resource
Vex Inventor’s Guide (Insert): Smart Charger • 1