Electric bilge pump example
From KayakWiki
Contents |
[edit] Description
This is the second version of the bilge pump in my kayak. The first one used an electric switch that I waterproofed. As well, there was an AGM battery (a type of sealed lead-acid battery) stored in the rear compartment. This meant wiring through the rear bulkhead and the battery was taking up room in the compartment. The switch suffered a mechanical failure, so I decided to replace it with this system.
The only components I replaced were the battery, battery case and the switch system. Instead of an electric switch, I decided to use an air switch and an air button. The batteries are AA NiMH batteries, 12 in series, with a capacity of 2300mAh. The battery case is a Pelican dry box.
Air switches are made for use where water is present and represents a shock hazard. They are sealed and waterproof. The switch is activated with air pressure. An air button - basically a small button that compresses an air bellows - is connected to the air switch with a one-eighth inch internal diameter plastic tube. Pressing the air button turns on the switch - pressing again turns it off. There are also momentary contact switches, so if you want to buy one, make sure you get the toggle type.
These switches are often used for pools, spas, whirlpool and hot tubs and similar home products. I bought the switch and button at a pool and spa supply store. The are not cheap, but are made to handle wet environments.
I've used this pump a lot in pool sessions, where I get a lot of water in the kayak. The only problem with reliability is that the white battery holders shown didn't hold the batteries tightly. After a while, one battery would work loose. I've replaced the battery holders with better made versions and the problem was solved.
Overall, the system is a bit pricey. However, I find the air switch system to be a lot more reliably and easier to use than the electric system I used previously. The switch is out in the open (since it can handle continuous submersion without problem), while the electric switch was inside the cockpit. The battery case is relatively expensive as well, but is completely waterproof, enabling me to put it in the cockpit instead of being in the rear compartment.
[edit] Photos of the installation
[edit] Overall view of the rear of the kayak cockpit.
This shows the air button (A) on the left and the water outlet thru-hull fitting on the right (B). The deck was reinforced with a layer of fiberglass tape before holes were drilled to place the button and thru-hull. Both holes were just over 1 inch in diameter.
The pump body and battery case are resting on the rear deck.
[edit] The layout of the pump components behind the seat.
The pump base is there, but the pump body was removed. The picture is a composite of two photos, hence the line near the centre. The black bungies in the centre (above D) are to hold the seat backband in position and are not part of the pump system.
- A - 1/8" inside diameter air tube that connects the air button to the air switch. The bitter end (above the A) is plugged into the air switch when the battery case is installed. It looks like it goes thru the bulkhead, but it doesn't.
- B - Check valve to prevent water from returning into the kayak.
- C - Outlet hose
- D - Pump base. This allows me to remove the pump easily. The pump body twists and locks into place.
- E - Rear of coaming
- F - Seat Back
- G - 3M Marine Dual Lock Fastener (a Velcro-like tape that uses mushroom-shaped bits that stick together; very strong).
[edit] Pump and battery in place
The rear of the kayak cockpit with the pump body and battery case installed. The battery case is at an angle to make it fit comfortably.
[edit] Air button shown pressed
The air button when pressed. It depresses almost 1/4 inch.
[edit] Battery case details
This shows the battery case open. From the left there is:
- A - Air Switch. The white part is a waterproof plastic part that connects through the case to the air hose. The black part is a conventional micro-switch.
- B - Battery holders - two six-cell holders were used. All cells are wired in series resulting in 14.4V 2.3Ah capacity.
- C - Underneath the wiring there's a white, inline fuse-holder. The pump requires a 2A fuse.
[edit] Battery case without cell holders
This image shows the battery case with the cell holders removed.
As you can see, the cell holders use conventional 9V battery clips to connect them to each other.
The fuse holder is easier to see here as well.
[edit] Air switch coninector
Another view of the battery case showing the connector for the air hose. That's not water on the case - it's Aquaseal used to seal the hole through which the air switch is threaded.
The velcro-like fastener can be seen on the case as well.
[edit] Wiring outlet
Another view of the battery case, this time showing the wiring coming out the other side. I couldn't find a waterproof electrical connector that was affordable. I glopped Aquaseal around the wire to ensure it's waterproof. There are two holes - one for each wire. The wire is knotted both inside and out of the case.
