our battery is situated somewhat away from our electronics and our wire barely reaches the board. instead of getting larger wire and crimping the terminals, it was much easier for a solution that I have pictured below. (obviously we will be taping up those contacts), I wanted to check if such a solution was legal in the rules. any comments?
Not for competition. There may be only one pair of SB connectors.
R47. The one (1) ROBOT battery, a single pair of Anderson Power Products (or APP) 2-pole SB type connectors, the one (1) main 120-amp (120A) surface mount circuit breaker (Cooper Bussman P/N: CB185-120, CB185F-120, CB285-120), and the one (1) CTR Electronics Power Distribution Panel (PDP, P/N: am-2856, 217-4244, 14-806880) shall be connected with 6 AWG (7 SWG or 16 mm2) copper wire or larger, with no additional devices or modifications, as shown in Figure 10-9.
If you want to use longer than 12" of cable, put it on the robot side, because if the battery cable is longer than 12", it no longer falls into the weight exception in R5b.
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along that same vein it says that the wire must have no additional devices or modification, I would consider 2 wires soldered together as a modification
if you do not have the capabilities or the time, andymark offers the service of custom length robot power cables
If hydraulic crimps arenāt your speed (or budget) 95 has had wonderful success with this style crimper in the past:
Solid copper termination from aforementioned hammer crimper:
Youād have a hard time convincing me that soldering 6awg wire is easier than one or two decent hammer swings and $20 spent at amazon. Plus you get to yell āhadoukenā at the top of your lungs when hammering it.
On a related note - ouch, that voltage dropā¦
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R61. Branch circuits may include intermediate elements such as COTS connectors, splices, COTS flexible/rolling/sliding contacts, and COTS slip rings, as long as the entire electrical pathway is via appropriately gauged/rated elements.
Note that the battery-main breaker-pdp circuit is NOT a branch circuit.
would that mean Iād literally have to weigh the cable?
and what if I solder the wire to make it longer to make it have only one pair of sb connectors? would that be considered okay?
as I just mentioned and GeeTwo said as well, splicing wires is a modification which is prohibited, and as GeeTwo mentioned this is not a branch circuit, so those rules allowing splicing are not viable here
No; if the cable between the battery and its connector is longer than 12", the battery assembly has to be weighed with the robot. If you have an 80 lb robot, no problem. If you have a 120 lb robot, big problem. Note also that if your battery cables are longer than 12", you would have a lot harder time if you wanted to loan or borrow a battery.
Iām hoping one of the LRIs checks in, but I donāt think so. This would constitute a splice, which appears to be disallowed on the 120A circuit.
3946 has a spool of 6AWG zip cord from Powerwerx.
AndyMark and Powerwerx will also custom cables for you if needed.
only if by lengthen, you mean make new cables,then yes, the entire assembly from battery to PDB is protected by R47, so the same issues of no additional devices or mods applies
What sort of iron did you use to solder those 6 AWG wires? Has the solder actually flowed into the strands of the wire? Does the solder joint survive a pull-test?
If the solder has not flowed smoothly in between the strands, you may have a ācold solder jointā that breaks apart at an inopportune time and/or has high resistance, reducing the power to your motors.
You are better off getting an appropriately sized crimper and making custom length wires. Even better still, relocate the PDP and motor controllers to the half of the chassis nearest the battery to reduce the length of the current loops and the loop resistances.
Lastly, your breaker is located well inside your frame perimeter. Depending on what you build on top of your chassis, it might not meet the requirements of R50 causing your robot to fail Inspection.
You are located in the midst of a lot of well established teams. It may be of great benefit to you and your team to ask some of them to look over what you have built and what you intend to build to make sure it is legal and will work well. Karthik suggested going to this link for help.
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^^ what @philso said. Also, to need as much cable as youāre showing, Iām wondering how high off the carpet your battery is. As heavy as the battery is, you should normally put it low so the robot doesnāt fall over too easily.
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If you add a piece of 3/4 inch plywood across the bottom of the chassis in the side where you have the battery, you can use this battery holder and install it closer to your PDP so you do not such long battery wires. I would recommend replacing the bungee cord with strips of Dual Lock to keep the battery in place. Of course, this only works if you are not planning to install something in that space.
The plywood has the added benefit that it triangulates the chassis so it doesnāt āparallelogramā when you get hit in a corner.
the solder has flowed through every strand. itās so strong that I would even trust my own weight to be supported under it. Iāve tried as hard as I possibly could to pull it apart. it will not even wiggle
the battery is mounted using the default mount in the kop. itās low and in line with the chassis. the reason I would want to extend it is simply because I want to give the cable enough slack to mount one of those connectors at the little bracket vertically. it would make it much easier to connect/disconnect the battery
we have considered our breaker placement. we donāt quite plan to have it covered by anything. Iāll keep it in mind. weāll probably move its placement
Plywood isnāt necessary for these; thereās an aluminum plate which supports the inner edge of the battery.
Itās actually pretty easy to surface mount the robot-side connector horizontally and insert/remove the battery connector. Just be sure to mount the side with the āplastic shieldā side of the connector against your structure, with the unshielded side having a bit of clearance.
If I were considering putting an extra solder or crimp connection on the 120A circuit, I would definitely want to get a Q&A ruling on whether this is allowed. If you do, be specific about what youāre doing and ask if this would be incompatible with the āno additional devices or modificationsā portion of R47. The broader you ask the question, the more likely you are to get a non-answer.