SLA or LFP Accessory Battery for your Kayak

In a short period of time Fishing kayaks in most cases a single user vessel have begun using many of the electronics that power boats use. Portable power has become a necessity. Running Fish Finders on a battery pack of AA batteries is a thing of the past. In the present we have Fish Finder/Chart Plotter combos, kayak lighting, and  the ability to charge battery powered devices while away from home is important.

Previously we built a waterproof battery box for a fish-finder/chart plotter. Since then there have been many advancements in batteries. This article explains the difference between the traditional Sealed Lead Acid Battery (SLA) and the latest Lithium-iron-phosphate battery (LFP). Here I list the pros and cons of both. You make the decision!

A SLA battery

SLA Battery Pros:

• Inexpensive (Economically Friendly)
• Fully Sealed Package
• Rechargeable
• Recyclable

SLA Battery Cons:

• Poor weight-to-energy (8 lbs 12aH)
• Cannot be stored in a discharged condition
• Inconstant discharge voltage
• Limited number of full discharge cycles
• Lifespan (300 charge cycles)
• Sulfation
• Memory
• Not Environmentally Friendly
• Contains Lead

There are many cons to the SLA battery for use on a kayak the first being weight. The 12aH SLA will weigh in at 8 lbs. That’s a lot of weight to travel with on any kayak. Battery life is another issue you may get a season or two total out of the lifespan.

New and improved Lithium-iron-phosphate batteries (LiFePO4 or LFP) are slowly replacing Traditional SLA batteries. Although still pricey LFP batteries have many advantages over the previous generation technology of SLA’s.

LFP Battery Pros:

• Excellent Weight-to-energy (3.5 lbs 12aH)
• Very constant discharge voltage
• Low Discharge Rate compared to SLA
• Rechargeable
• No Memory (Can Be fully Discharged without cell damage)
• Lifespan (2000+ charge cycles 5-10+ years)
• Recyclable
• Thermal and chemical stable aka Safer (as opposed to Lithium Ion cells)
• No Environmental Thermal concerns (provides maximum output at hot or cold temps)

LiFePO4 Battery Cons:

• Cost (Expensive)
• Contains Phosphates

Looking forward to this conversion. Will report on the experience in the near future.

Jackson Kayak has really simplified the installation of fish finders for the end user first with the Big Rig and now with its new offshore kayak the Kraken! Like the Big Rig the Kraken is Raymarine Dragonfly ready. This means the Lowrance HDI skimmer also fits really nice in this scupper with the Lowrance Scupper Mount Kit! This article covers how to install a Lowrance skimmer transducer & Fish Finder on the Kraken in a scupper hole so the transducer is in the water.

Things you will need:

• Lowrance HDI Skimmer
• Lowrance Scupper Transducer Mount Kit
• (2) West Marine Wire Cap
• Drill with 1″ hole saw
• Philips head screw driver
• 2 waterproof butt connectors
• 3/8″ diameter x 4″ long heat shrink tubing

Install:

First unwrap the transducer cable from its packaging and twist tie. run the wire from the hull through the scupper up to the deck . Unboxing the scupper mount simply follow the diagram. With the HDI/Chirp skimmer you will simply slide the transducer on the track at the bottom of the transducer mount. It needs to be positioned forward on the mount so slide the track all the way up to where the wire goes inside the transducer. Now Slide the foam insert and then through the top bracket that will fit perfectly to the scupper. Using the wing nut thread it all the way down to the top bracket to snug it up. Once snug you may now clip the threaded plastic off flush with the bracket and clip the cap over.

Now to run the transducer wire to the inside of the kayak.  Using a 1″ diameter hole saw drill through the radius area of the hatch. BE careful as the plastic is ver thin here. Once the hole is made runt he cable through the wire cap and screw the wire cap in using the screw driver. The screws will self tap.

Next for wiring back to the fish finder unit and battery. This is really up to you where you would like the location to be. I tend to keep it out of the way of where fishing line cannot fowl with the wires and also so adjusting the location of the fish finder on the fly. Also take into consideration the factory installed battery box tray between the front day hatch and the center hatch (7). In my case the fish finder location is to be on the center hatch tracks and being fully adjustable to slide the entire length of the track. The decision to run the wired through the deck in front of the center hatch in my case was the conclusion. This location allows the wires to swing and not get int he way when operating the hatch. The next step will be fabricating a track mount console that will allow me to mount the fish finder to the center of the hatch.

To connect the battery using a plug connector first slide a 3-4″ x 3/8″ diameter heat shrink tubing over the bare wire side of the Lowrance power wire. Crimp the butt connectors to the wires with the  correct polarity and heat shrink the connectors. Then slide over the 3/8″ heat shrink tubing and shrink  the connectors in. I prefer to use clear heat shrink tubing due to all of the use int he salt water. Sometimes connections fail and have water seep in. This speeds up the trouble shooting as now the corrosion is detectable visually.

Complete!

Installing electronics on a kayak can bring on many challenges. One of the major challenges are how to wire through the kayaks bulkhead and what products are manufactured to cap large drilled holes post wiring the fish finder. This article covers common Types of Hull Pass-Throughs.

After a lot of research here are a few types of hull pass-through caps for wiring electronics on your kayak.

Rubber Stopper 1/4″ – 1.5″ Drill

Commonly used for drain plugs and scupper holes the Rubber stopper can also be used for Thru Hull Wiring. Simply with a sharp box cutter cut a slit from the outer diameter to the center hole. This will allow you to pass the wire into the center of the stopper. Runt he connecting plug through the hole and simply press the stopper in small diameter of the flange first to make a seal. This method works but is not recommended for a permanent install. The stopper over time can come loose so check it every now and then. It wouldn’t hurt to silicone them in.

Cable Gland 1/4″ – 1″ Drill

The cable gland is a wiring connector that is able to match wire diameters with a grommet that seals tightening down a lock nut.

On the bottom of the gland is a threaded portion that is able to pass through a drilled hole in the hull and tightened down with an included ring nut. Cable glands do work great but the only problem i see with them is the protrusion they create. They are easily snagged by fishing line. In areas that fishing line will not snag they are great.

Cable Clam pass through 1″ – 2″ Drill

Cable clams are a good solution but protrude the most. They require 4 large screws holes perfectly aligned. Personally I think they are the most unsightly for applying on a kayak. They are purposed more for boats. They are also the most expensive and hardest to install.

TH Marine CeaCap 3/4″ Drill

The CeaCap is the most flush option but will only work with cable plugs that will pass through a 3/4″ hole. It is threaded and will turn the wire 90 degrees so it is flush with the hull. IT will allow for two 12 gauge wires to pass through.

West Marine Wire Cap 1″  Drill

The best out of them all I have found for large connectors is the West Marine Wire Cap. Fish finder connectors with 1″ diameter will work with this cap to cover the required hole to pass through the wire for both the transducer and the power. You may run two wires at 14 gauge through this cap max and 1 wire at 8 gauge id say max.