I am creating this to ask for wiring tips with organization, placement, ect. I have been looking to improve the wiring team on my team and I thought this would be the best way to improve for next season.
Keep it clean. Use as many zip ties as you need and have routes for your wires. Run signal wires away from power wires, so try not to cross them or tie them together. Lay out all of your electronics in an easy to access area before screwing them down. Place your ESCs close to your PDP and label them all either with numbers, or a name so you know what is controlling what. You can use some white shrink wrap for labeling wires that have a long run to a motor or sensor as well. I.E, we use numbers to label, so we would put a #1 on the circuit breaker, a #1 on the ESC, a #1 on the shrink wrap on the power wires, and a #1 on or near the motor.
Just route your wires where you can get to them, and keep it tidy.
Currently what my team does for wiring is do all the power first. Every power wire on our robot is in a twisted pair to allow tracking of wire sets easily, and to keep the bundle together without a million zip ties. We connect all of our power wires together, securing the ones near other together to keep everything tighter. For data, we essentially just run the wires near a similar path as power, just in their own little bundle to keep power and signal away. Our wiring isn’t amazing but when looking at our robot, you primarily see about 4 bundles of wire, 2 going to the back (each side of drivetrain) and then two going to the front (signal one side, and power the other side).
When possible, we like to run our wires up tubes. It can become a pain but it made wiring look good this year on our elevator. We ran it inside the tube to the top, where we had a hole that led into our cable carrier. This is the second year we have does this.
Plan out where everything is going before you start wiring. Know where your motor controllers are going to go, where you need to get power too, where you are going to need to get power to. Drawing this out helps a ton.
One thing I forgot to add that we have done the past couple years is mount motor controllers on what we call bricks. We bend small little pieces of aluminum and adding mounting holes for motor controllers. This year, we had a 8 775 Pro drivetrain, and we just had 2 bricks that contained the motor controllers in a tight little spot. Our elevator we had a brick that contained 2 SRXs and 2 Sparks.
This will obviously change from year to year but if you are able to, have a separate electrical board that you can assemble externally from the robot and install after. It is much easier to organize and make your wiring clean when you don’t have to compete for time with mechanical and don’t have to deal with the confined space of a robot.
Don’t leave wiring until the very end. The more rushed you are, the messier your wiring will be.
Design the electrical board and placement of components with the wiring in mind. For example, facing PCM and VRM power ports towards the power supply ports on the PDP. Also, Keeping components that come and go from the same place together. Such as keeping motor controllers together and PCM and VRM together since the wires generally come from the same place. Therefore, you only need to run one bundle of wires instead of multiple wires through different channels.
Overall, just start with the mentality that you need to design for clean wiring since you almost are never able to take an existing electrical board designed without wiring in mind and make it clean.
First thing is to plan your wiring runs before you start doing them – think through where you need to route all the wiring to get from where your main electronics will sit to the various actuators. If at all possible, place your electronics where you can see all of the status lights without having to stick your head all the way into the robot. If you plan to make troubleshooting easy, you usually don’t have to do as much of it.
Protect the integrity of your wires now to avoid having to troubleshoot shorts later. Watch your bend radius - wires don’t like sharp 90 degree turns. Don’t run through holes in the frame without a grommet to protect the wires. Don’t run wires over sharp edges, metal or otherwise. If you are using zip ties to hold the wires in place, don’t haul them so tight they damage the insulation – you want a comfortably firm hold, not to choke it to death. Try not to route the wires through invisible places like the inside of structural box tubing, because it increases the risk that mechanical will blindly drill through it later. Wire loom (the stuff that looks like vacuum cleaner hoses) and other similar products can be very helpful in protecting your wires.
Avoid making banjo strings. Include a service loop/strain relief at each connection point. The idea is that you should be able to disconnect the wire without cutting any zip ties, and the weight of the wire should not be on the connector. This is helpful both when you need to do maintenance and to prevent unexpected mid-match disconnects because of acceleration or connector wear.
Label all wires at both ends. It makes troubleshooting much easier.
Wires consume power in direct proportion to their length. The bigger the wire is/the more current you’re running over it, the shorter you would like it to be, because you want your power going to the end devices, not to heating up the wires. DO NOT compromise your service loops for this. Just try to position things to make the needed length of wire as short as possible – mount the battery near the main breaker and PDB, etc…
Wires running in parallel induce voltages, wires running perpendicular do not. If you must cross signal and power cables, make sure it is at a right angle.
If you are having problems with electrical things now, first try to figure out what the problem is. If wires have loose connections, then you need to spend time learning how to make good connections, and practicing doing so.
Perhaps you need to have a couple students do some research into how to do this well. I know we’ve had problems over the years when we don’t have serious mentor involvement in the wiring process, with a mentor who has lots of experience with electrical stuff. It takes some effort to train students how to do this work, or have them learn on their own, but it pays off.
Yup, I probably should have explained that, but I was also trying to say to simply keep them away from each other. Crossing wires at a right angle is sometimes needed, but I personally try to avoid power next to signal entirely.
Consider building your own battery wiring harness.
Battery -> SB50 pair -> main breaker -> PDP
A custom harness will allow you to remove some of the constraints on component placement within your robot.
6 AWG welding cable is readily available and far more flexible that stock materials.
6 AWG compression lugs are also readily available - periodically check ebay for an auction on a box of lugs.
SB50 connectors with 6 AWG contacts are also available on ebay.
Hydraulic crimpers are also available from a number of sources, including Harbor Freight.
One of the things that isn’t including but I highly recommend is to use ferrule crimps on all 20 awg weildmuller connections(especially CAN bus)
Yep. Just highlighting that parallel is bad, perpendicular is OK.
The label wraps around the wire nicely, and then a clear portion wraps over the label protecting the print and making the label flush with the wire with no flags or tags.
What is the best board type to mount on? Does perforated polycarbonate work well from andymark?
My team in the past uses polycarbonate since it is easy to tap, and is a good protector of shorts to the frame (if one occurs before discovered). A mentor that was involved in 2009 for a different team said they used polycarbonate and it helped a ton with the static electricity generated.
The perforated polycarbonate works great for us. We went from regular polycarbonate to that and it really helped us do our wiring better and quicker. Also, most wire management tubing, etc. is a trap. Zipties and or pool noodles work better imo.
Don’t cheap out on connectors/crimpers. It seems like a good idea to buy the cheapest version of a crimp when you’re at the store, but you will be kicking yourself when the robot dies in the middle of a match because the battery crimps snapped or a wire fell out due to a loose crimp.
I could probably make some tutorials on how to source & make various connectors, use 4awg wire, etc. if people are interested.
See teams 254 and 1538 and older pics of 968 robots.