Power system
Estimated time: 30 minutes
This page describes how to set up the power system, which supplies power from the SLA battery to the motors and encoders.
Power cable assembly
- 5mm hex key
- 5/64" hex key
- Socket wrench with 10mm socket
- Electrical tape
- Zip ties
Assemble the power distribution panel (PDP) and power cable using the following procedure:
- Connect the power cable and 120A circuit breaker to the PDP
- Use electrical tape to cover any exposed connections, and use zip ties to secure the tape
- Install the eight 40A breakers into channels 0-3 and 12-15
- Install the 5A breaker into channel 4 with the terminal spacer
See video (4x speed):
Note
Make sure that all of the power cable connections are tight! Loose connections can be very difficult to troubleshoot.
Note
The 5A breaker needs a terminal spacer because the terminals are too long (left photo). The spacer covers the exposed terminals to help prevent accidental shorts (right photo).
Tip
Double-check the polarities of the power cable connections. Red goes with plus and black goes with minus.
Tip
The FRC robot wiring guide might be a helpful resource here.
Battery assembly
- Socket wrench with 5/16" socket
- Adjustable wrench
- Electrical tape
- Zip ties
For each sealed lead acid (SLA) battery, connect a battery cable (battery comes with screws, nuts, and washers) and use electrical tape to cover the exposed terminals. See video (4x speed):
Note
Make sure the battery cable connections are tight! Loose connections can be very difficult to troubleshoot.
Tip
Double-check the polarities of the battery cable connections. Red goes with red and black goes with black.
Motor power
- WAGO tool
Connect the power cables of all 8 motors to the PDP. See video (4x/16x speed):
Note
In this step, we are temporarily wiring the motors and encoders for bench testing.
Note
Some people may find the WAGO connectors on the PDP challenging to work with. Here is a close-up video demonstrating their usage (2x speed):
As shown in the video, the WAGO operating tool should be inserted straight into the actuation slot at a slight angle to horizontal. Then, the end of the tool should be pushed downwards to open the slot.
We also recommend watching this video explaining how WAGO connectors work: WAGO connectors explained
Note
Do not forcefully wiggle the WAGO tool or pry the end of the tool upwards! Doing so can deform the plastic housing, making the connector harder to operate in the future.
Tip
If you are having trouble getting the wires to go all the way in, look inside the wire insertion slot. Since the wires are thick, it is not sufficient for the slot to be partially open (left), it needs to be fully open (right):
Encoder power
- WAGO tool
- Wire stripper (22 AWG solid)
To build the encoder wiring harness, start by using 22AWG wire to make one 45cm cable and two 30cm cables. Strip 1 cm of insulation from the ends of the wires. Next, connect the wires using two 5-port wire connectors (one for red and one for black), and add inline wire connectors to the free ends of the 30cm cables. See photos for reference:
Note
Be sure to strip at least 1 cm of insulation. If there is not enough exposed wire, the WAGO connector may clamp onto the insulation, resulting in intermittent power to the encoder.
Use the wiring harness to connect all 4 encoders to the PDP. See video (2x speed):
Setup complete
At this point, the power system setup is complete and you should be ready to connect the SLA battery. Make sure to double-check the polarity of all power connections (power cable, battery cable, motors, encoders) before proceeding. Once the battery is connected, all motors and encoders should light up, indicating that they are powered on.
Note
For battery charging instructions, please see the Usage page.