Subject: 12V refer instructions

From: Q Myers <[email-masked]>
Date: Thu, 15 Aug 1996 20:01:35 -0700

Instructions on building a 12VDC refrigerator. 8/15/96

For the last four years I have been using a very small, super
efficient 12 volt refrigerator, that I put together for less then
$400.00 in a couple afternoons. My object here is to provide
enough information to enable the “Do it Yourselfer” to construct a
similar and maybe better refrigerator.

Specs:

Capacity: 1.7 cubic feet.
Power requirements: 12VDC (10.5 to 16.5) at 4 amps while
running.
Run time: about 6.6 minutes per hour. (your mileage may vary)
Temperature: Unit has small freezer compartment, entire unit can
function as a freezer.
Exterior Size:  Height 25.5 inches, Width 25.5 inches, Depth 28
inches.
Weight: about 35 lbs.

Parts List:

*Sanyo 1.7 c.f. refrigerator.
This same unit is sold under various brand names including
Kenmore, Avanti, Gibson, and others. Current Cost $99.00 to
$119.00.

*Danfoss BD2 compressor and matching controller.
This can be ordered from an appliance parts wholesaler or retailer.
You may have to do some persuading to get them to track one
down for you, but my local wholesaler here in the small town of
Bend Oregon was able to deliver a unit in less than 48 hours. Cost
was about $200.00 in 1992.

A note about refrigerant: The refrigerator you buy could be
charged with either R-12 or C-134a. See the sticker on the back of
the refrigerator. Be sure to specify refrigerant type when ordering
your compressor.

*Extruded polystyrene foam
*Glue suitable for foam
*Shower board
*1\2 inch wooden dowel
*Piano hinge
*Various other hardware
(purchase at your local builders supply store)

Getting started:

I recommend getting the compressor installed, and the unit
running before adding the extra insulation. If you make it as easy
as possible for the refrigeration tech to mount and test the new
compressor, you will save on labor costs.

Building the compressor mount:

Use a couple pieces of angle iron or aluminum to build an
extension to the original compressor mounting structure. The idea
is to mount the new compressor farther away from the back of the
refrigerator box to allow for the addition of extra insulation. Leave
the old compressor in place for now, but get the new mount drilled
and ready, and attach it to the new compressor, so it will be easy
for the tech to attach with the nuts and bolts you will provide. The
tech can add tubing where needed to attach the new compressor to
the existing system.

Wiring:

You will need to have the wiring in place and ready to go for the
tech because he/she will not be familiar with 12 volt compressor
wiring. Follow the wiring diagram that comes with the Danfoss
compressor and controller. The existing thermostat will work fine.
You must also provide the tech with a battery because the tech will
need to run the unit during installation. I would recommend
connecting color coded battery clips to the main power wire to
avoid a reverse connection to the battery. Remember, the tech will
not be familiar with this wiring set up, so make it as easy and
foolproof as possible.

Sealed system work.

Find a local refrigerator repair shop that doesn’t mind getting into
something a little out of the ordinary. Provide the shop with
refrigerator, compressor, controller, mounting brackets, battery,
wiring diagram, etc.. Explain to the tech why you want the
compressor mounted farther away from the back of the box, and
make sure he/she understands the wiring diagram. The tech will be
able to do the rest. The sealed system is the same as any ordinary
refrigerator.

Testing:

Before going to all the trouble of adding insulation, which is the
hardest part of the job, give the unit a good test for a few days. If
there is a problem, you should find it now.

Adding insulation.

When you are satisfied that the unit works, its time to increase the
efficiency by adding insulation. If you want to skip this step, and
can live with a bit more power usage, you can permanently mount
the controller, and call it done. Now it’s time to start gluing on
foam. The bottom, sides, and top are straight forward. Remove the
door and hinges and glue on as many layers of foam as you want.
Be sure to use glue that is compatible with foam or you could end
up with quite a mess. This glue comes in caulking tubes and is
available from building supply stores. Try to keep things square,
and keep the front edges of the foam even with the front of the
refrigerator.

On the back, remove the screws holding the condenser in place
and very gently pull it away from the back of the box a few inches.
NOTE: Be very careful not to flex the tubing too much, or it could
crack or kink. Cut some pieces of foam to fill the space where the
old compressor was mounted, and add some foam between the
condenser and the box. Then fill the nooks and crannies with spray
foam.

To mount the condenser to the foam back, make some 1/2 inch
holes in the foam behind the mounting brackets, glue in some
short pieces of dowel, and secure the brackets to the dowels with
screws.

Shower board:

Cut the shower board for the top, bottom, and sides, and glue it in
place. Cut the front piece to allow enough space for the door
gasket to seal against the metal of the refrigerator box around the
opening.

The door:

Cut two or three slabs of foam to the right size for a door.
Laminate them together and glue shower board to all six sides.
Remove the inner door liner and door gasket from the old door by
folding back the gasket and removing the screws. Attach it to the
inside of the new door with the same screws. Placement is critical
because you want a good seal when your door is mounted. Attach
the door using the piano hinge screwed into the shower board with
sheet metal screws. You may need to add a shim of wood or metal
to the hinge to get a flat seal between the door gasket and the front
of the refrigerator box. Find an appropriate latch for the door at the
local hardware store.

Finish up:

Finish out the unit by adding edge molding, rubber feet, etc...

Disclaimers:

I do not guarantee that everyone will be successful at building this
unit. Only those with some basic knowledge and experience
should attempt it.

This article and associated photos may be reprinted and distributed
freely.

If you get stuck, or need some clearer instructions or photos, email
me at [email-masked] and I will do what I can to help. This
information will also be posted at this url by 8\19\96
http://www.teleport.com/~qmyers/refer.html 

Good Luck,

Q
-- 
Q Myers
http://www.teleport.com/~qmyers
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