replica eveready #477 battery
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EverReady #477 Battery Substitute
For Portable Tube Radio Sets
October 2011
Many portable tube radio sets were designed to use a
67½ Volt “B” battery. An original EverReady #477 “B”
battery is shown on right side of this page. In this
paper I will describe how to make a nice-looking
substitute battery for the #477 type, using seven low-
cost 9-volt transistor radio batteries.
I saw a YouTube video showing a replica #477-type
battery that used six of the #A23 12-volt alkaline
batteries. But the #A23 has only between 30 to 40 mAH
capacity when the load is between 10 to 5 mA,
respectively. Therefore such a battery has a useful
life, for typical portable tube radios, of at most 4
hours. The total battery cost is up to $24 ($8 per #A23
2-pack from Radio Shack), plus tax.
Another approach, which is cheaper and more common, is
to use seven 9-volt alkaline or “heavy duty” transistor
radio batteries that are stacked and wired in series.
The capacity of the “heavy duty” type in this service
is about 250 mAH, for a useful life of at least 25 to
30 hours in a typical portable 4-tube set. My total
cost for seven “heavy duty” 9-volt batteries from
BigLots was $3.33 plus tax ($1.90 per 4-pack). I have
chosen this approach.
The width and length of a standard 9-volt battery are such that the
stack will be about 1/32” thicker and about 1/32” narrower than the
specified maximum dimensions for the #477. You should use one of the 9-
volt batteries to check that your battery compartment will accept the
slight additional thickness. My stack of seven 9-volt batteries is 4 and
5/8” long, while the finished battery is to be about 5 and 5/16” long,
not including the snap connectors. See drawings below and on the next
page.
In order to keep the finished width within #477 width, the terminals of
the 9-volt batteries must be soldered using small (AWG22) wire jumpers
placed on the inside edges of the 9V snap connectors. I used rubber
bands to hold the battery stack together while installing the series
wiring. I used a small chisel-tip professional Weller iron. I tinned
each connector and jumper first, and then held the jumper onto the
connector for as short a time as possible to make a good joint. Avoid
excessive heating of the connectors. See photo below;
This “heavy duty” battery stack measured 70.5 volts after the partial
assembly shown above. The rubber bands and the temporary wood block will
be removed during final assembly.
The snap connector block is fabricated from salvaged snaps and a
homemade 5/8” thick wood base. To make the snap connector block, I used
left-over pine base molding to make two 5/16” thick wood blocks which I
then glued together using a very small amount of Elmer's white glue.
Here is a template drawing for making the wood blocks. I suggest using
cereal box cardboard to make the template.
The “B” battery snap connectors must typically be
salvaged from old batteries or scrap (non-restorable)
radio sets. The snap connectors are mounted to the
wood block spacers using the #18 wire nails passed
through the connector rivets. Carefully drive the
nails through the rivet holes of your connectors and
into the blocks, using a tap hammer and an upside-
down and slightly larger flat head nail as a nail-
set. Check that the rivet heights of your connectors
kept the 5/8” long nails from poking through the back
of the wood block unit, or else use shorter nails. I
cut shallow grooves in one side of the block to pass
the snap connector wiring back to the battery stack.
Secure the snap connector block to the battery stack
with rubber bands while wiring the snap connectors to
the battery stack, taking care to observe polarities
(positive = battery male, negative = battery female).
Using the cereal box cardboard, make a 15/16” x 5 1/4” strip to lay over
the connectors of the battery stack. This will help to protect the
connectors from possible punch-through and shorting during handling and
installation of the finished battery. I suggest placing the unpainted
side of the cardboard towards the batteries.
Make a 6 3/4” x 5 1/4” plain paper inner wrap to support the battery
assembly. Use short strips of cellophane tape to fasten down snugly the
plain paper over-flap. This inner wrap does not fold over the ends of
the assembly. If you don't do this inner wrap, the replica label will be
harder to place and install. I used cellophane tape strips to secure the
replica label to the battery stack. On next page are photos of 1) the
finished replica battery, and 2) my Emerson model 850 set with this
battery and my G cell adapters installed.
The finished battery will not have the beveled sides of the #477, but
otherwise should look and perform very fine in many sets that required
the #477.
On the next page is my replica paper label, sized to this stack design,
that can be wrapped around the finished battery assembly to provide
support and aesthetic quality. The under-flap is on the left. Use the
grid (1-inch centers) to check and adjust image size before printing.
THE END
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