Waterproof Kayak Battery Box for Lighting
- ncsinkers
- Nov 22, 2018
- 2 min read
A simple flexible waterproof battery box for lighting, gps, etc..
Item List
1. Pelican 1120 case
2. 12V 8Ah battery
3. 1/2" push to connect fitting (Liquifit, SMC, Parker) with 1/2"NPT or 3/8" NPT thread. Alternate is a Swagelok 1/2" tube fitting with 1/2" nylon ferrules. These can be found on ebay for less but the push to connect is a much cheaper option. You may have to drill/bore through the fitting to open it up a little on the inside.
4. 1/2" OD tubing (PVC, Poly, Nylon, or anything easily available at Lowe's or Home Depot) to length. Slightly more rigid and larger ID recommended as push to connect fittings work better with more rigid tubing and the larger ID will allow more room for feeding wiring through.
5. RTV silicone and/or epoxy
Link to video showing the setup. Additional details below.
Drill a hole in the top of the 1120 case and tap (cheap tap will work for plastic) the appropriate threads for the push to connect fitting. Install the fitting and seal with epoxy or RTV. Note: RTV and epoxy will not likely stick well to the poly case but will likely add additional protection.
Feed electrical wire (with soldered or joined section) through the 1/2" tubing and seal the wiring at both ends of the tube with RTV and/or 2-part epoxy. This will keep water from entering the tubing leaving the internal wiring much more protected (abrasion wear or pulling) and a clear or semi clear tube will allow you to see if there are ever any issues with water ingress. Feed the tag end of the wires through the push to connect fitting and into the battery box. If you stagger the crimp connectors slightly when installing them, this will allow them to go through the push to connect fitting more easily. Push the end of the sealed tube into the push to connect fitting. This will create a waterproof seal from the outside of the box in.
Secure the 12V battery using foam such as polyethylene foam, styrofoam, or other. Although I did not install a fuse, you may want to look into this for safety.
The push to connect or Swagelok fitting (don't over tighten the nylon fittings they are meant to be reusable) will allow you to remove the 1/2" OD tubing and lighting setup from the box when done. This is good for storage and also allows you to install another device such as a fish finder.
The disadvantage of this setup is that there is not an on/off switch that is easily accessible. A reed switch can be used as an easy means to turn on and off the lights using a magnet. This provides a completely waterproof switch option. I used a normally open (N/O) glass reed switch and embedded it into a rigid tube for protection. A switch with a plastic enclosure or other form of protecting the glass may be a better option. A neodymium cylindrical magnet was tethered to the tube so it could be slid into position activating the reed switch and then slid away to turn off the lights. The reed switches I used would sometimes remained closed when removing the magnet but a physical tap would eventually cause the switch to turn off.
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