Evening star., 1922-06-14
EI \. HYATT VERRILL,
Expert on Radio Technology,


1t is not at all difficult matter to
recharge your own storage batteries
or certain makes of b batteries II
a liJJie care is used. To do this
yourself is a great convenience, for
it is always = nuisance to have to
send your battery out and wait for ii
to be Ttchargcd.
Those who, do not wish to rig up
their own recharEinS apparatus may
purchase them ready made. Ready
made outfits are not expensive, but
You can save money by making your
own.
First ascertain the kind of current
used in your house lighting equip
ment. In the majority of cases IL is
alternating current, usually of 1lO
volts. but in some places direct cur
rent is used. Either one may be en-
ployed for rechdrgiug the batteries.
but the apparatus to do the recharS-
ing VIII depend upon the sort of cur
rent available. If your current is 4
direct current the outfit Will be very
simple. but if alternating it will be
q tribe more complicated.
To arrange an' outfit for recharginS
with direct current examine your DAT
terry until you find the mark lndl-
eating the charging rate in amperes.
II you cannot find ii, ask the dealer
or maker from whom you buy the
battery, for this is most important
matter. Having determined TINS. op-
tain as many ordinary siXteen-candle-
powrr carbon filam6nt inCandeScent
lamp bulbs and sockets as there are
ampcrcS in the charging rate ana
connect the batteries as shown IN the
cut. leading the wire \ TO terminal
or binding post. To another posi-
beside this attach the Wire Is anu
fasttn the other end of this and the
end of the wire & 10 the two contact
points of a double pole switch, as
shown. For the next step you must
determine which of the two wires ID
or { is the negative and which the
positive. You must be extremely
careful to have the negative wire
attached TO the negative end or the
battery, and vice versa.
To find which wire is positive OF
negative, connect the wires from the
electric light circuit to the blndlnS
posts DD, leaving the switch OPEN
and connect the two wires EE TO the
switch-arm posts. Then NIL Jar OF
glass with water in which salt mas
been dissolved, dip the two wires t.E
i'll the water, being sure that they
cannot touch, and throw on the
switch BY Watching the bubbles
which rise from the ends of the wires
you may easily recognize the positive
wire and the negative wire, Tor the
most bubbles will rise from the mega
tive. Then mark the binding post
on the switch to which this Wire is
attached so you can identity 1t anu
throw off the switch.
Connect the Two wires EE to your
battery. fastening the negative wire
to the negative post and the positive
wire to the positive post, and throw
on the switch. The length of time
required to charge the battery VIII
depend upon the extent to which it
has been used. The best way to de-
termiuc when ii * fully charged Is
TO use a Noltmeter, being sure to
throw off the switch when testing.
DO not as is sometimes recommended,
use q double-throw, double-pole
switch which may be used to throw
tho charging current into the bat
terry or the battery current into your
receiving set. If you always remem-
ber to throw the switch and are very
careful such an arrangement may be
very well, but accidents will happen,
and If by chance the switch should
be short clrcuited or a contact made
with the set while using it serious
results might follow.
1t is only a moments work to dis
connect the wires EE from the set
and connect them with the charging
switch and it ohviates all danger.
Instead of a couple of binding posts at
ID. YOU may use an ordinary electric
light plug if you wish. and then, by
using a flexible cord with attach