Updated LiPo Starter Battery Box V2

Jim Johns

I found that the original starter battery box I built several months ago had several disadvantages after using it for a short while.

  • The box wasn't rigid - it had a lot of flex that I didn't like.
  • The 1/4" wide wire ties stretched too easily and didn't hold the starter firmly. They were also prone to slipping off the starter, especially if the starter turned on the uprights during use.
  • The box itself was a little longer than I liked, making it impossible to carry it on my Goldberg Handi-Tote. It didn't fit very well in my toolbox that I carry to contests either.

I spent some time looking for better materials and finally found some I liked at Lowe's. Here are the parts I used for V2.

UPDATED 10-24-2018: The cover plate above didn't break, but it did warp from the pressure. Here's a metal one that should work even better.
 https://www.lowes.com/pd/Eaton-1-Gang-Gray-Blank-Wall-Plate/3569286

Note on this setup - this box has only slightly over 4" of space for the length of the LiPo battery. There is also only 1" of height, so anything thicker will require modification. I did a simple mod to accommodate the 4S LiPo I used for my primary.

I purchased my 3S and 4S LiPos from valuehobby.com. Both have T-connectors (Deans Ultra compatible) and both have more than adequate power to start an OS-95 4-stroke with ease. The 3S (11.1V) doesn't seem like it would have enough voltage to power a 12V starter adequately, but it works fine due to the high power density of the LiPo batteries. Thanks to Chris Berardi from the SPA West for the tip on using the 3S LiPo. Here are links to the batteries I used.

3S -- http://www.valuehobby.com/power-systems/batteries/3s-lipo/elite-30c-2200mah-3s-t.html
4S -- http://www.valuehobby.com/power-systems/batteries/4s-lipo/elite-30c-2200mah-4s.html 
Here's my spare starter in the original configuration (rear) and my primary starter in V2 configuration (front).
Here are the parts I used for the conversion. Links, full descriptions and part numbers are provided above.
  1. CableHider 1-Gang Outlet Box - it comes as 2 pieces (box & base) in a bag.
  2. Cover plate - color is optional if you plan to paint it.
  3. UtiliTech 24" x ½" Cable Ties
  4. Starter uprights from original version
  5. Paint of your choice. I used Gloss Black Rustoleum Spray Paint because I had it on hand.
  
The first order of business is to disassemble the original, including removing the uprights from the plastic box. The plastic box may be reused as you see fit. 

NOTE: If you are starting from scratch, see V1 article for instructions and materials to make the uprights.(https://seniorpattern.com/build_tips_starter_box.html)

Mark the cover plate for the uprights and drill appropriate holes for the screws to hold them in place. I located them on the flat area just outside the cover plate screws and used only 1 screw to hold each of them in place. Use what makes you comfortable, but remember that the entire starter, upright and box will be wrapped with a 1/2" wide cable tie.		  
Screw the uprights to the cover, keeping them parallel with the end of the cover. Here's one upright mounted and the other with the hole drilled.


CAUTION: Be sure to locate the uprights far enough toward the ends of the cover plate so it can be screwed to the box after the uprights are mounted. The uprights needs to be mounted so the entire countersunk area for the screw head is visible. See RED arrow.
Now for several slight modifications to the box.

Mod #1 (RED arrow): The box has tabs to hold the box tightly to the base when mounted to the wall. We don't need them because we'll be wrapping the entire box with the big cable ties. Besides, we want to be able to take the box apart if the LiPo battery ever needs replacement, so get rid of them. Sandpaper, a file, a Dremel cutoff wheel or even an Xacto knife will do the job just fine.

Mod #2 (BLUE arrow): Cut out a slot in the end of the box by following one of the lines molded into the inside of the box. This is where your battery wiring will exit the box to attach to the starter. Locate it slightly off center so you can center your battery in the box and have the wires come straight out without a bend. Clean up any sharp edges.

Screw on the cover plate and then do ONE of these two mods below depending on the battery you choose.

Mod #3A - if your battery is less than 1" thick such as the 3S LiPo above.

  • Use your Dremel with a cutoff wheel to cut off the excess screw that protrudes through the box material. This will keep the screw from accidentally penetrating the LiPo - NOT a good thing. See RED arrow for location and do this on both ends of the box.

Mod #3B - if your battery is more than 1"such as the 4S LiPo above.

  • Use your Dremel with a cutoff wheel to cut through the plastic and the screw on both ends of the box to get clearance for your battery. See BLUE arrow for location. I had to remove about ¼" for the 4S above. Don't worry - there's still plenty of meat to hold everything together.
That's it - the building is done. Here's the assembled box with the battery temporarily installed.
Remove the battery and paint the visible area of the box the color of your choice to complement or contrast with your starter. I didn't bother painting the bottom since it won't be seen in normal use, but you can do so if you like. Let it dry THOROUGHLY! I used Rustoleum Gloss Black because I had it on hand from another project. Rustoleum requires 24 hours to dry completely.
Pad you battery - I used ¼" foam rubber on the 4S version and stick-on Velcro on this one with the 3S LiPo. I also used a small Velcro strap to hold the battery firmly in place.
Slip the base into the box with both the power and balance leads protruding through the slot you made in Mod #2. Place the box on the base and press them together. You may need to press the four posts protruding from the base sideways to get them to fit into the box properly. Take your time.
Put a couple drops of Medium CA on the top of each upright where it contacts the starter. The starter can actually rotate on the uprights if you don't do this.

Mount your starter using the 24" x ½" cable ties around the starter, uprights and the box itself. Align the starter switch in the location YOU prefer. I like mine on the left side where I can activate it with my right thumb. Put the cable tie locks at the bottom of one side of the box. This is a square corner anyway, so it's one less place to create slack in the cable ties.

Tighten the cable ties as tight as you can get them - I used pliers to help.  I then cut the ends off, leaving about 3" of excess. I laid the starter out in the sun, let it soften the wire ties, then pulled them as tight as possible and cut them off flush.
I used a short strip of double sided stick-to-itself Velcro wrapped around the power wires and the rear cable tie to keep the excess wiring out of the way.

NOTE: That little white XH Molex balance plug is somewhat fragile, so protect it. Notice that I tucked it between the power wires for safety. You'll need it to balance charge the LiPo without removing it from the case. 
Here's my backup starter in V2 configuration. All that's left to do is the final tightening of the cable ties and cutting off the excess. I now have two great starters to use and share with friends who might need one.

You can add stick-on feet to the bottom if you'd like, but I haven't felt the need to do so.

TECH TIP 

Have you ever over tightened a wire tie so that it's too small for the task at hand? Me too - frustrating, isn't it? It is especially annoying with these long, wide cable ties because they are about 50¢ each due to their size.

Simply slip a #11 Xacto blade BETWEEN the lock and the clicking surface of the wire tie. Then you can easily open the wire tie to a larger size.