Fish finder battery box - watertight

He is an idea for the next guy or gal to build upon:

I bought an Outdoor Products watertight box from Wallmart - $10.

Drilled a hole in top, bought a super small gasket from the hardware store and 2 prong trailer connection, secured it with outdoor silicon - $6.

Drilled holes in bottom, secured scrap piece of 2x4, rounded off bottom, with small screws and silicon, so that the box sits of the bottom of the boat - $0.

Drilled holes in top and bottom of the box for two U bolts that connect to the Hobie post - $3.

All together, $19. Hobie makes a similar product for $18 (plus what ever the dealer fee would be) but it isn't watertight.

I wanted something that secured firmly to that post rather then free float around in the bottom of the kayak unsecured.

Pictures attached.

Will you be charging the battery while it's still in the kayak?

haha no that sounds risky. Will take the battery out for transport and charge at home. The 2 prong trailer wire connection was my first idea to quick connect to my power cable and let the box freely sit in the bottom of the kayak.....but thinking about swells and all I thought that box might shift around alot so I wanted it secure.....in retrospect the 2 prong connection is not needed, could just push the power cable thru the hole and seal with silicon.

haha no that sounds risky. Will take the battery out for transport and charge at home. The 2 prong trailer wire connection was my first idea to quick connect to my power cable and let the box freely sit in the bottom of the kayak.....but thinking about swells and all I thought that box might shift around alot so I wanted it secure.....in retrospect the 2 prong connection is not needed, could just push the power cable thru the hole and seal with silicon.

Use a waterproof cable gland to secure the wiring and make a watertight seal.  Better than silicon alone for pass through wiring.

I posted a description of a battery box which I made using an Outdoor Products waterproof box and a SAE two-pin panel-mounted connector at http://www.northwestkayakanglers.com/index.php?topic=17734.msg191025#msg191025 .  The panel mounted connector provides a secure and waterproof way to attach the battery box to a fish finder, and you can charge the battery without taking it out of the box by plugging a battery charger into the panel mounted connector.  I put a Fastex buckle strap on the box to provide a handle, and to provide a way to attach the battery box to a scupper hole tube, mast mount, or other attachment point inside a kayak.

I have this nifty removable battery box in my Thresher, but even with some modification it's not waterproof so last month I built a waterproof box for my battery and used a cable gland (like Crash suggested).  I had to buy a whole bag of them, so I have spares if someone needs a couple.  I looked at the Outdoor Products "waterproof" battery box like above, but after playing with the lid and the seal I was left thinking it's no more than water-resistant.  The lid is easily pressured open so any twisting or significant water pressure could get past that seal quite easily. I went with a Pelican 1050, also from Walmart.  About 10 bucks more but a more reliable box.  Not sure it will fit an AGM battery though.

The color was purely coincidence.

My SLA battery is water resistant all on its own. 

I am not sure why everyone is so adamant about a completely waterproof drybox for a SLA battery. Sure it is definitely advisable to keep moisture (especially salt) away from the contact points, fuse, and connected wiring, but that battery can handle weather without problem. Throw some silicone on the fuse connection (waterproof fuse holder) on the battery contacts, and dialectric grease on the two pole connector and away you go.

In the case of this design and placing, Lutefisk's hull would likely have to fill about halfway to truly compromise the silicone seal and allow water inside, in which case replacing the battery would be the least of my concerns. You're not likely to get much if any water in otherwise.

**DISCLAIMER**
If it's a lithium battery they absolutely are affected by moisture and a water tight seal is critical. 

I am not sure why everyone is so adamant about a completely waterproof drybox for a SLA battery. Sure it is definitely advisable to keep moisture (especially salt) away from the contact points, fuse, and connected wiring, but that battery can handle weather without problem. Throw some silicone on the fuse connection (waterproof fuse holder) on the battery contacts, and dialectric grease on the two pole connector and away you go.

In the case of this design and placing, Lutefisk's hull would likely have to fill about halfway to truly compromise the silicone seal and allow water inside, in which case replacing the battery would be the least of my concerns. You're not likely to get much if any water in otherwise.

**DISCLAIMER**
If it's a lithium battery they absolutely are affected by moisture and a water tight seal is critical.

The cable gland secures the wires and prevents pullout.  It isn't for improved waterproofing, it's for improved idiotproofing.  Don't ask me how I figured this one out.

Nice, but where's the fuse? 

I am not sure why everyone is so adamant about a completely waterproof drybox for a... [cut for brevity]

**DISCLAIMER**
If it's a lithium battery they absolutely are affected by moisture and a water tight seal is critical.

Because the thread was started with "here's something to build on" and I would hate for someone new to this to find the thread, throw in a battery or other device where it DOES matter (Lithium or otherwise) and suffer any unfortunate circumstances.  Technically, yes, an SLA battery will be fine.  The battery bank on my 44 footer that sank was STILL pumping juice to fans and bilge pumps the next day after I had it raised (freaked me out, too).  If you are building an enclosure and CAN make it waterproof at a reasonable price and thereby decrease the opportunity for t'ings to go wrong...why wouldn't you?

And I'm with Rawkfish on this one.  You DO have a fuse..RIGHT??? ;-)

Matt, I wanted to put my SLA's in a box to keep everything - okay, just the battery and the fuse holder - together in one place where my renowned klutziness wouldn't have much chance of unplugging something.  Watertight was a secondary consideration.  The Outdoor Products boxes are cheap at Wally world and are just the right size, and when I found two lead SAE connectors similar to those pmmpete uses (they're used for watertight rooftop connections on RV's and are easy to find at a dealership), I figured I'd just go waterproof.

After I had one fuse quit on me (on the bench), I found I can keep spare fuses and a tube of dielectric grease and other knick-knacks in the box, too, so it became more than a just-a-battery box.

lutefisk_n_chips, if you haven't secured the battery inside the box, it's a good idea.  You can use pieces of foam or pool noodles to hold it in one spot.  I use small tabs (1-inch square) of adhesive-backed Velcro attached to the battery and to a wall inside the box to keep mine in position.  Just don't use big pieces of Velcro - it makes it darned hard to get the battery out.  DAMHIK.

If you open the lid of the box and attach the charger to the SAE trailer connector, it shouldn't create any more of a problem charging the battery in the hull than it does charging it on the bench.

Makes sense all!!! Coincidentally I am building a waterproof battery box for a lithium battery setup, the cable gland is the way I am going with it.

And definitely you need the fuse, although I am just going to hope and assume that it's connected outside of the box somewhere   

If anyone needs cable glands in Salem,  i bought a bulk pack on Amazon and have more than i need. 

If anyone needs cable glands in Salem,  i bought a bulk pack on Amazon and have more than i need.

I’m not in Salem but if your in my area chasing crabs, rockfish or salmon. I’d be down for 4 extra, I’ll trade ya for my catch if the day fishing with ya!