not to scale.
Name.
Length × Diameter.
Contacts:
Raised area Positive.
Flat end Negative.
Zinc Chloride
Alkaline
Do not confuse with the LR48 watch battery, which is also numbered as 8.
Remember the plastic torches in the 70's that used an Ever Ready battery that was 2 small batteries in a cardboard tube? Yes this is that battery! (showing my age now!)
Very difficult to find now and quite expensive when you do (typically £5 - £6), you can "make" one from a 123 camera battery (typically £4), some card, electricians tape and a small bolt. See below for method. The Lithium camera battery will last longer than the original Zinc batteries.
Equivalents:
2 Cell Bijou, 2010, 2B, 2R10, 2R10R, 2R10S, 2T10, 8, 259, 757, 2010, 3010, BA6105, Duplex, Ever Ready No.8, GP210S, K609, No.8, Number 8, T8, V0004, V8, V3010,
| Image not to scale. | Common Name. | Dimensions. Length × Diameter. | Chemical Composition. | Nominal Voltage. |
|---|---|---|---|---|
|
| Duplex. | 74.6 mm × 21.8 mm Contacts: | Zinc Carbon Zinc Chloride Alkaline | 3 volts. |
To make a sleeve to replace this battery with a readily available 123 camera battery you will need a few things:
TIP: If you are going to use a fresh 123 battery to check for sizing and as a mandrel, stick a piece of tape over one end so that you can't inadvertently short it out while handling it.
1; Wrap the 123 battery with a few turns of tape or a single wrap of card held on with tape, just to make it slightly thicker. This is now your diameter size gauge and final wrapping mandrel.
2; Take the bolt (yellow in the picture at the bottom) and round over the threaded end slightly, just so there are no sharp edges. Also file the head so that it is nice and flat, this is where the positive "pip" of the 123 will sit. The finished length of the bolt needs to be between 40 and 42 mm from flat head to end of thread.
3; Cut a strip of card wide enough to rest on the bolt head and cover all of the thread except the last 4 mm or so (red in the picture).
4; Use a piece of tape to hold the end of the card to the bolt thread and wrap the card tightly around the threaded end of the bolt until the card is flush with the bolt head, use more than 1 strip if needed, fixing the ends with tape to stop it unwinding.
5; Cut another strip of card, this time to cover the whole length of the bolt and head except for the protruding 4 mm of thread (brown in the picture).
6; Wrap this card around the bolt until the diameter is 18 to 19 mm (slighty larger is fine, smaller and the 123 won't fit, check for size against the gauge you made in stage 1).
7; Cut another strip of card 70 mm wide, fix to the card/bolt piece and start wrapping around the whole thing (blue in the picture) except for the protruding 4 mm of thread. Use the mandrel from stage 1 to get things lined up (yes it should protude a bit).
8; Keep wrapping with 70 mm wide card until the outside diameter reaches 21.5 mm (slightly less if you're going to add a label) then wrap the card with 2 layers of tape to secure. If the mandrel is still fitted remove it (if it's the fresh battery you can take off the extra wrapping and non shorting tape now.
9; (you can leave out this step but the varnish will make it more durable) If you want you can make a label to stick on to remind you what it's for. Now give it a coat of the varnish to give it some added strength, using an artists brush to coat the inside.
10; Once dry it is ready to use. Slide the 123 into the tube "pip" end first, the rear of the 123 should just be proud of the edge of the tube. Insert into equipment and switch on. If it fails to work check that you haven't got varnish on the bolt head or thread end.
You coud use other batteries, for example 2 × "N", would do the job, and alter the sizes accordingly but the 123 gives excellent performance and is the closest generally available size.