RE: [Paddlewise] RFI electric bilge pumps

I have been experimenting with an electric bilge pump system for two years.
Like Bob, I found the switch to be the weak link in the system.  For the
past year I have been using a SPDT switch with a rubber boot over the
toggle.  In addition to using the immersion safe waterproof switch, I
mounted the switch on the rear deck so that the guts of the switch are in
the rear compartment.  The switch mechanism is further protected by
enclosing it and a fuse in a 10 oz. round plastic food container.  My 7 AH
gel cell battery is mounted in the rear compartment as well.  My pump is a
Rule 1100.  I have had no problems with leakage or corrosion with this
setup.  I paddle in freshwater except for winter pool sessions, so I cannot
speak to saltwater corrosion.  I did have a AA battery pack for my compass
light fail due to corrosion from chlorinated pool water.  I will be
enclosing this battery pack in a waterproof box.

Motorcycle batteries have liquid electrolyte and will spill sulfuric acid
out of the vent tube when they are tipped.  Gel Cell batteries are vented
through a valve and have their electrolyte in a gel form.  One trade off for
the gel electrolyte is that the batteries cannot sustain high draw as well
as the liquid electrolyte batteries can, however I have not had a problem
with the battery overheating during use.  In my new boat I am intending to
use a 2 AH gel cell battery.  I also found a sealed switch designed for use
on jet skeets <g> at West Marine for $38 US. For those who want further
redundancy on battery protection there are rigid plastic boxes available
from Campmor that will fit a 7 AH gel cell.  I have seen a box branded as an
Otter Box that might be big enough for this battery.

The key to what I think is a successful electric pump system is putting the
vulnerable components, switch, battery, fuse and connections in a relatively
dry environment and using redundant protection where ever feasible.

Dana

-----Original Message-----
Date: Thu, 6 Apr 2000 22:20:08 -0400
From: "Bob Volin" <bobvolin_at_bestweb.net>
Subject: Re: [Paddlewise] RFI electric bilge pumps

Hi to Ulli, Christine, Eddie, and anyone else with the stomach to consider
electric pumps again..

Ulli, you mention the Paddlewise topic page on electric pumps,
http://www.paddlewise.net/topics/boatequip/elecpumps.html

Here is an update on the system I described in the last post of that page.
It all works well except the switch.  Christine, you are absolutely right
about salt water:  it will corrode where it is allowed to get in.  The
original switches were inexpensive Radio Shack push-on push-off models that
I enclosed in plastic project boxes which I attempted to seal with plastic
sheeting, tape and gobs of aquarium sealer.  Just a very few drops of
moisture got in to both switches (Joan's and mine) and corroded them by the
end of the season.  Joan's switch failed in a January pool session. Mine
hung in there, but I found it to be corroded when I took the assembly apart.

So I went out and spent $37 each for switches that are designed to be
submersible.

The rest of the system, including soldered connections that were more
exposed that the switches were, is intact.  All the connections were sealed
with silicone sealer and wrapped with tape.  The battery is in a sealed
plastic container within the sealed forward hatch.  The battery is the
sealed, "maintenance free" type.  I learned that it's a good idea to vent
the sealed container after use, although I have not had a problem.
Apparently, gases given off by the battery can be corrosive to the
terminals.  These can be protected with a healthy dose of silicone grease
(found in auto stores to protect trailer hitch connections).

Bottom line, Ulli et al., is that the configuration that I described does
work and is functional (now that the switch has been upgraded).  Other
systems have been successful as well.  The important thing is to seal the
switch and all connections carefully and to check them with reasonable
regularity.

Happy pumping!

    Bob V
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