Assembling the Battery Packs

Version 2.4

Materials

 * Battery Pack Nylon Tubes (2)
 * Battery Pack Rubber End Caps (4)
 * Lead Wire -18 awg
 * Spring Terminals (2)
 * Button Terminals (2)
 * Small Acrylic Circles (4)

Tools

 * Soldering iron + solder
 * 5 Minute Epoxy (Hysol for better seal, but takes more time) with applicator + nozzle
 * Wire cutters
 * Wire strippers
 * X-acto knife or sharp scissors
 * Helping hands (helpful)
 * Hot glue gun

Procedure
Step 1: Cut four 1m lengths of 18ga wire.

Step 2: Strip one end of each of the wires.

Step 3: Tin each of the recently stripped ends.

Step 4: Tin both spring terminals and both button terminals as shown.

Step 5: Solder the wires to the terminals as shown.

Step 6: Hot-glue the terminals to the blue acrylic circles.

Make sure to position the spring terminal so that you are able to bend the wire through the notch on the side of the acrylic circle. Hot glue to hold it in place.

On the button terminal, bend the wire through the notch to the other side, for a loop and return through the notch going the other way. Hot glue.

Step 7: Cut a small hole in two of the rubber endcaps as shown. Take special care of the placement of the hole--it should be right where the notch on the acrylic circle would sit if it was up against the endcap. It should be big enough for two wires to fit through and nothing else.

Step 8: Push one spring terminal lead wire and one button terminal lead wire through the newly made holes in the endcaps as shown.

Step 9: Setting the terminals in place.

First, push the button terminal through the nylon tube. Next, put the spring terminal flush with tube as shown.

Next, position the button terminal about 20mm above the end of the tube. To get this distance exactly right, if you have the batteries already, make sure the button terminal reaches the top of the batteries with a very small amount of play. Once the length is correct, make sure there is a little slack in wire going to the button terminal so that the wire can lay on the inside of the battery tube while batteries are present.

Place the wire going to the button terminal in the notch of the blue acrylic circle that is glued to the spring terminal. Use hot glue to hold it in place.

Step 10: Use hot glue to hold the spring terminal in place.

It works better to simply use a little hot glue at this point (just enough to hold it in place) since too much wont allow the epoxy we're going to use next to form a good seal.

Step 11: With end endcap upturned and away from the tube, use epoxy with an applicator to coat the bottom of the endcap and about 5-10mm of the sides liberally. Using gloves for this and the next step is advised. '''Note: In this photo we are using an epoxy we had lying around in the lab, but other waterproof epoxies may work. Check to make sure that the epoxy will bond to the vinyl endcaps. Use a liberal amount to assure a good seal, but not so much as to overflow and prevent the spring from being able to compress.'''



Step 12: Carefully seat the endcap in place while simultaneously pulling the wires out the holes in the end of the endcap.

Once it is in place, place upright for the curing of the epoxy so that none leaks over the battery terminals or blocks the tube.

Older Versions:
Version 2.3

Materials
 * Battery Pack Nylon Tubes
 * Battery Pack Rubber End Caps
 * Lead Wire -18 awg
 * Spring Terminals (2)
 * Button Terminals (2)
 * Small Acrylic Circles

Tools
 * Soldering Iron
 * 5 Minute Epoxy (Hysol for better seal, but takes more time)
 * Way to mix epoxy



Steps
 * 1) Measuring Battery Lead Wire - Cut one length of 36 cm and two of 1 meter 
 * 2) Strip the ends of the wire in preparation for soldering. Tin the wire tips for easier application. 
 * 3) Create a hole in the rubber ends for wire pass-through. Thread the 36 cm through the rubber ends (see video). Follow with the one meter wire, one through each of the rubber ends. (Again, see video for appropriate layout.) 
 * 4) Solder a spring terminal to one end of the 36 cm wire and a button terminal to the other end of the 36 cm mire. Solder a button terminal to the 1 meter wire that goes through the same rubber end as the spring terminal (on the 36 cm wire), and solder a spring terminal to the other 1 meter wire (with the button terminal of the 36 cm wire). 
 * 5) Mix epoxy and attach acrylic circles to back of battery terminals. As the video highlights, it can be hard to deal with 4 loose acrylic circles, 4 terminals, and springy wire pulling the terminals out of the epoxy. Alternatively, you could use double sided sticky tape to hold the circles down to a work surface, to hold the wires down flat, and to hold the corner of a terminal down to the circle while the epoxy cures. It helps to sand the acrylic disc prior to this for a good gluing surface.[[File:openrov56 small.jpg]] 
 * 6) Debur/Sand/Prepare the nylon tubes. Feed the wires through to measure wire length for epoxy end caps (see video for better explanation). 
 * 7) Watch the video for this first. Add epoxy to the pass-through rubber caps and carefully pull the acrylic-attached terminals into place.    