When I first got my kayak I loved it, and I still do, but I wanted to add a fish finder to it. Since I normally fish in deeper water I thought that a small inexpensive fish finder would really help me to find those finicky bass. My biggest obstacle for this idea was how I would get power to my finder. After some research I found out that my finder could be powered off of a power wheels 12 volt battery. So my next thought was how to keep this battery from getting wet. After scanning many outdoors forums I found out that this Plano ammo box is pretty water proof. So I set out to find the materials I would need for this simple battery box! While I was making it i decided to add a car charger port as well, just in case my phone ever died while I was on the water. I hope you enjoy and that maybe this can help someone out there!
Step 1: Materials & Tools
So this build doesn't really require too many things! While every fish finder is different I will be referencing the one I own for this build. I will include images for all the parts you will need!
1) You will need your fish finder. I have the Garmin Striker 4
2) A Dry Storage box too house the battery. I chose the Plano 131252 Dry Storage Emergency Marine Box, Orange
3) A power source. The one I chose to use was CB CHROMEBATTERY 12V 7AH Sealed Lead Acid (SLA) Battery Piranha MAX 160 Fish Finder. The blue stuff around the battery is just a foam knee pad i put around to make it a snug fit in the box.
4) You will also need a way to charge this battery. I went with a Sealed Lead Acid Battery Charger UPG D1724
5) A Blue Sea Systems CableClam, this will be for the fish finder cord to pass through the box and connect to the battery.
6) A Electop Dual USB Socket Charger 2.1A & 2.1A with LED + 12V Power Outlet Cigarette Lighter Socket, Triple Function Panel for Car Marine Vehicle Motorcycle ATV. I chose this so that I can also hook up a phone charger or anything else that will plug into a USB or cigarette lighter outlet. You DO NOT need this part if you only want to power your fish finder!
7) Insulated electrical connectors, the sizing of these depend on the size of your wire, battery connectors and charger connectors.
8) A set of Alligator Clips I chose red and black to keep the connections easy to see.
9) Lastly, some silicon marine grade sealant.
-Drill and various drill bits
Step 2: Preparing the Cable.
So to start this project we begin with the cord of the fish finder, every cord and finder is different so just make sure you do what applies to yours. For mine it has one end that plugs into the unit and the other end has exposed wires for the wiring process. We will only be using the red and black wire for this project, so just wrap up the other two and tuck them out of the way. For the red and black attach any type of insulated connector you would like. I used insulated female disconnect terminals. This was just for an easy way to connect and disconnect to the battery.
Step 3: Box Preparation
So this is where we start to make the overall projects.
We will begin by choosing a drill bit that is slightly larger than the ports of of the 12v plugs. you want to make sure that the holes are only slightly larger so that way we have less area to seal up with the silicon. It is very important that we keep the box as watertight as possible, we do no want any of the wires or battery to get wet. After you have drilled out the holes that are need for the charger area make sure smooth over the edges with a utility knife or even sand paper if you have it. it is time to insert the 12v chargers into the holes you drilled. first dry fit to make sure everything is correct, then once you are satisfied make sure to use a generous amount of silicon on the back plate and around the edges to ensure a tight seal. Also, use the silicon on the threads of the screws when you screw them in. You can run a couple beads around the inside if you would like as well. just make sure to try and clean up any mess before it dries!
Next we will move on to the actual wire for the fish finder. It will be the same process of choosing a bit slightly larger and drilling the hole. But, this time we will be using the CableClam for the wire. You want to make a small slit in the black membrane of the CableClam for the wire to pass through. Then Dry fit and finally use the silicon when attaching the CableClam to the box. Before moving on, just make sure that you haven't missed anywhere with the silicon! It is always better to have to much than not enough!
Step 4: Box Interior
Now we move on to the inside of the box.
I found that when I first put the battery inside it moved and slide way too much than I liked. So I solved this problem by using some foam I had laying around. The foam piece I used was made for kneeling on when doing gardening, but any foam that you can cut down will do. I first cut a piece for the bottom so the battery would sit on a padded surface, then I just cut the shape of my battery out of the middle of the remaining foam and all of it is just friction fit into place.
With the battery inside the box we move on to our wires. since we have already applied the connectors to the fish finders wire we can easily slip them onto the battery terminals associated with the correct colors (red/positive black/negative) and the fish finder should turn on! The alligator clips are used to also run power from the battery terminal to the correct sides of the plugs, which should be labeled. Yet again I chose the color coordinated method. You do not have to use alligator clips if you want to have the chargers always hooked up, just choose some other type of connector that you would like. I chose alligator clips so that I could have everything disconnected and they would only be able to be used when I chose to.
Now everything should be working, as long as your battery is charged! just take the time to organize the wires anyway you want and you are set!
Step 5: Take It for a Test Run!
Now that everything is done go ahead and plug some things in! As you can see in the pictures I have my finder plugged in and powered up, I also have my flashlight charging as well (the little red light is on). And that is it, now get out on the water and find those lunkers that are hiding deep!
Also, the box is big enough to put the charger and everything in for when it is time to store it after a long day! just make sure you unhook your wires so you don't drain your battery before the next trip!