Add Battery Article (wpilibsuite#1262)

Co-authored-by: Dalton Smith <daltzsmith@gmail.com>
Co-authored-by: sciencewhiz <sciencewhiz@users.noreply.github.com>
Co-authored-by: jasondaming <jasondaming@gmail.com>

source/docs/controls-overviews/control-system-hardware.rst

@@ -79,9 +79,9 @@ Robot Battery
   :alt: Robot Battery
   :width: 500
 
-The power supply for an FRC robot is a single 12V 18Ah battery. The batteries used for FRC are sealed lead acid batteries capable of meeting the high current demands of an FRC robot. For more information, see the datasheet for the `MK ES17-12 <https://www.mkbattery.com/application/files/2515/3308/8109/ES17-12.pdf>`__.
+The power supply for an FRC robot is a single 12V 18Ah Sealed Lead Acid (SLA) battery, capable of meeting the high current demands of an FRC robot. For more information, see the :ref:`Robot Battery page. <docs/hardware/hardware-basics/robot-battery:Robot Battery Basics>`
 
-.. note:: Other battery part numbers may be legal, consult the `FRC Manual <https://www.firstinspires.org/resource-library/frc/competition-manual-qa-system>`__ for a complete list.
+.. note:: Multiple battery part numbers may be legal, consult the `FRC Manual <https://www.firstinspires.org/resource-library/frc/competition-manual-qa-system>`__ for a complete list.
 
 Robot Signal Light
 ------------------

source/docs/hardware/hardware-basics/index.rst

@@ -10,3 +10,4 @@ Hardware - Basics
    wiring-pneumatics
    status-lights-ref
    preemptive-troubleshooting
+   robot-battery

source/docs/hardware/hardware-basics/preemptive-troubleshooting.rst

@@ -14,11 +14,11 @@ Check Battery Connections
   :alt: Trying to wiggle the battery terminal by hand.
   :width: 500
 
-The tape the should be covering the battery connection in these examples has been removed to illustrate what is going on. On your robots, the connections should be covered.
+The tape that should be covering the battery connection in these examples has been removed to illustrate what is going on. On your robots, the connections should be covered.
 
 Wiggle battery harness connector. Often these are loose because the screws loosen, or sometimes the crimp is not completely closed.  You will only catch the really bad ones though because often the electrical tape stiffens the connection to a point where it feels stiff. Using a voltmeter or Battery Beak will help with this.
 
-Apply considerable force onto the battery cable at 90 degrees to try to move the direction of the cable leaving the battery, if successful the connection was not tight enough to begin with and it should be redone.
+Apply considerable force onto the battery cable at 90 degrees to try to move the direction of the cable leaving the battery, if successful the connection was not tight enough to begin with and it should be redone.  This :ref:`article <docs/hardware/hardware-basics/robot-battery:Robot Battery Basics>` has more detailed battery information.
 
 Securing the Battery to the Robot
 ---------------------------------
@@ -29,8 +29,13 @@ Securing the Battery to the Robot
 
 In almost every event we see at least one robot where a not properly secured battery connector (the large Anderson) comes apart and disconnects power from the robot. This has happened in championship matches on the Einstein and everywhere else. Its an easy to ensure that this doesn't happen to you by securing the two connectors by wrapping a tie wrap around the connection. 10 or 12 tie wraps for the piece of mind during an event is not a high price to pay to guarantee that you will not have the problem of this robot from an actual event after a bumpy ride over a defense. Also, secure your battery to the chassis with hook and loop tape or another method, especially in games with rough defense, obstacles or climbing.
 
-120 Amp Circuit Breaker
------------------------
+Securing the Battery Connector & Main Power Leads
+-------------------------------------------------
+
+A loose robot-side battery connector (the large Anderson SB) can allow the main power leads to be tugged when the battery is replaced. If the main power leads are loose, that "tug" can get all the way back to the crimp lugs attached to the 120 Amp Circuit Breaker or Power Distribution Panel (PDP), bend the lug, and over time cause the lug end to break from fatigue. Putting a couple tie wraps attaching the main power leads to the chassis and bolting down the robot-side battery connector can prevent this, as well as make it easier to connect the battery.
+
+Main Breaker (120 Amp Circuit Breaker)
+---------------------------------------
 
 .. note:: Ensure nuts are tightened firmly and the breaker is attached to a rigid element.
 
@@ -42,9 +47,15 @@ In almost every event we see at least one robot where a not properly secured bat
   :alt: Applying a twisting force to the second cable on the breaker.
   :width: 350
 
-Apply a twisting force onto the cable to rotate the harness.  If you are successful then the screw is not tight enough.  Split washers might help here, but in the mean time, these require checking every few matches.
+Apply a strong twisting force to try to rotate the crimped lug.  If the lug rotates then the nut is not tight enough.  After tightening the nut, retest by once again trying to rotate the lug.
+
+The original nut has a star locking feature, which can wear out over time: these may require checking every few matches, especially if your robot-side battery connector is not attached to the chassis.
+
+The nut is normally a relatively uncommon 1/4-28 thread: ensure this is correct if the nut is replaced.
+
+Because the metal stud is just molded into the case, every once in awhile you may break off the stud. Don't stress, just replace the assembly.
 
-Because the metal is just molded into the case, every once in awhile you will break off the bolt, ask any veteran team and they’ll tell you they go through a number of these every few seasons.  After tightening the nut, retest by once again trying to twist the cable.
+When subjected to multiple competition seasons, the Main Breaker is susceptible to fatigue damage from vibration and use, and can start opening under impact. Each time the thermal fuse function is triggered, it can become progressively easier to trip. Many veteran teams start each season with a fresh main breaker, and carry spares.
 
 Power Distribution Panel (PDP)
 ------------------------------
@@ -53,7 +64,8 @@ Power Distribution Panel (PDP)
   :alt: Battery terminals on the PDP.
   :width: 500
 
-Make sure that split washers were placed under the PDP screws, but it is not easy to visually confirm, and sometimes you can’t.  You can check by removing the case. Also if you squeeze the red and black wires together, sometimes you can catch the really lose connections.
+Make sure that split washers were placed under the PDP screws, but it is not easy to visually confirm, and sometimes you can’t.  You can check by removing the case.
+Also if you squeeze the red and black wires together, sometimes you can catch the really lose connections.
 
 Tug Testing
 -----------