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Hi Rick. Congratulations on your new adventure.
The voltage used is usually determined by what the major components
require. My psub project is using Minnkota S101 salt water trolling motors. I
have elected to use four of the same type for ease of maintenance. I can keep a
couple of "spares" with me when I'm out exploring, simplifying a replacement
should it be needed.
I bought these from some nice people on line at www.trollingmotorparts.com and the
price was very reasonable.
The speed controllers that are available through them are simple
"plug-and-play" and the whole system has been designed and manufactured by a
reputable company who is the industry leader in this type of motor.
Minnkota has conducted a lot of research and development in producing
their line of products, and I would bet that we would have a tough time putting
together a system as reliable or efficient in power usage as these.
There are some methods of upgrading the seals to ceramic type, and much
information is available through psubs archives and member's advice on the
options for pressure compensating the motors for deeper operation.
The motors I'm using are 36 volt, and draw 46 amps at full throttle, so I
will be using battery banks at 36 volts each. The motor controllers are
designed specifically for these motors, are fairly inexpensive, completely
sealed in epoxy, and most importantly, easily replaced should one fail. I'm a
big fan of "off-the-shelf " parts because I don't want to be out some where and
broke down because I can't get the parts to fix the sub.
Many of the electrical items we use can be adapted from automotive or
marine applications. Other than the thrusters, 12 volt devices are very common
on cars and boats, so that's where we can find some of the things we need.
Because I don't want any shafts penetrating my pressure hull, I've
opted for electrical systems for all of the external devices. For me, the
simplicity of electrical connectors and actuators makes a lot of sense. My
rudders, dive planes, and future manipulator arm are all powered by 12 volt
linear electric actuators. These are "off-the-shelf " actuators designed for
automobile applications. sealing them is the key.
Control is achieved with simple "rocker " switches making the task of
installation very simple, and replacement is both inexpensive and quick. The
hull penetrators are small, and completely sealed with epoxy, minimizing
the chance for leaks. Each thru-hull has a ball valve on the inside, with spade
terminal connectors so if a leak develops, I can pull the wires off and close
the valve.
With a simple battery switching system, fuse blocks, and a small on-board
supply of replacement parts, I hope to be able to affect repairs, should it be
needed, and minimize the dangers of failed systems.
To me, simplicity and redundancy are the biggest advantages to keeping the
sub operational under differing conditions.
Here's a couple of pictures of the system and parts I'll be using on my
sub.
http://www.frappr.com/?a=viewphoto&id=1578526&pid=10875159&myphotos=1
Although I'm the only one I know of taking this approach, I'm confident
that with a little tinkering, I can make this system both convenient and
reliable.
Good luck with your project, and I hope to be able to see your sub when
finished.
Frank D.
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