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B126 pack

 
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B126 pack

Post by Michael Watterson » Wed Mar 28, 2012 12:25 pm

There are 4 main options to fill it.

10 x PP3
156 x CR2032 (actually cheaper!) as 6 parallel stacks of 26 coins via 1N4148. Needs a Wooden holder & fuse.
3V to 7.5V using AA or C cells and an Inverter. This is not a good idea.
Rechargeable cells of some kind (least good idea).

To fit 10 x PP3 the internal space must be 68 x 95 x 50 minimum.
Very late model Ever Ready boxes are not large enough!
The GEC max size is 70 x 98 x 51 which means if you use 0.5mm thick card max the Internal will be 68.5 x 95 x 50 worst case! The batteries can be laid out to avoid the top socket
Top view
Code: Select all
Top layer cells (oo is bottom two holes of socket)
[__][__] 
    00[__]
[__][__]

bottom layer of celld
 [__][__]
     [__]
 [__][__]

(Note Kodak batteries seem too fat). The Cells are in 3 groups plugged into each other.

+[ ][ ][ ][ ]- +[ ][ ]- +[ ][ ][ ][ ]- So 3 x PP3 connectors cut in half are needed.

One row x 4
middle x 2
one row x 4

Top & bottom are less 3 card thickness. = 0.5 x 6 = 3mm
depth is one thickness front & back = 0.5 x 2 = 1mm
width is one thickness each side and one tab = 0.5 x 3 worst case (not whole way) = 1.5mm

The CR2032 are unsurprisingly 20mm diameter and 3.2mm thick. So you have top view:
OOO
OOO

60mm x 40mm + insulation. Max insulation is thus 8.5mm x 10mm. A drilled block could have 2.25mm ends and 2 x 2mm internal walls minimum on width and 2.5mm ends and 5mm internal wall on depth.
26 cell is 83.2mm high, leaving 11.8mm for socket 6 x 1N4148 diodes and top + bottom connectors. A block of wood 68 x 85 x 50 can be cut & drilled. A safety fuse is also required!

 

Re: B126 pack

Post by Mike C » Sat Apr 14, 2012 1:23 pm

These things are a tight squeeze to make up unlike larger HT batteries where you have plenty of room inside to work with, the layer cells inside are roughly PP3 size but its the PP3 battery cases that take up room, with this battery its not as easy as clicking together 10 PP3s as there is no room unlike the B136 which is easy to make up.

 
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Re: B126 pack

Post by Michael Watterson » Sat Apr 14, 2012 4:09 pm

Agreed. But seems to fit with 2 x blocks of 4 and 1 x block of 2. It's right at the edge of "legal size" for a B126.
I have put suitable scans in the technical library.

 
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Re: B126 pack

Post by Michael Watterson » Thu Aug 23, 2012 10:19 pm

B126 using PP3 156 x CR2032 is a viable option.

Print Ever Ready or Vidor livery at correct size. (See Tech Lib or PM me) on 90gm quality paper, not card. Printer card is too thin.

b126_versions.jpg

Glue down on on printed side of a cereal packet with Pritt.

glue_down.jpg


(I prototype with laser print to save cost of expensive inkjet)

Glue the seams leaving the bottom flaps open.

Making the connector

You need 2 x pieces of plastic the size of the top and some coffee tin or similar. Marge tub base for lower sheet and lid for cover.

Use a fine screw driver to poke holes and twist tip of scissors to enlarge it
connector1.jpg


connector2.jpg


Put two slots in plastic at arrows and bend tabs through to solder wires to on reverse.

Make a cereal box card frame.
card_frame.jpg


Glue overlapping join to rear of connector panel.

Cut three PP3 connectors in half and connect one pair to the two coffee tin pads (cut out in card)

Glue packing and card to frame at the middle for two batteries. The middle layer at connector is two batteries and the the two outer layers are four batteries,
threesets.jpg


Make up two short leads to join the two batteries in the middle to the four on either side that connect to the socket.
pp3sx10.jpg


The unit is easy to refill and slides into the case from the bottom. The bottom of the cartridge can have a velcro square and then the 3 tabs cut around it and then the matching velcro on the outer flap.

Kodak batteries and some others will not clip together. Zinc Carbon are most likely to fit and 450mAH @ the 8.5mA typical HT vs 590mAH for typical Alkaline. So 45 to 50 hours depending on set.

Press on the sides of the packs. It's the depth of three PP3 packs vs depth of B126 is very tight. If the bare sides are loose your outer box is too large!

The width of the B126 should have no space to spare vs width 2.5 PP3 packs (overlap).

packed.jpg

 

Re: B126 pack

Post by ultrasheep » Sat Oct 13, 2012 9:22 am

Are some PP3 batteries thinner than others? If so which are the best brands to use? I found that if I had a stack of three it was too thick to fit in my Ekco BP123.

 
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Re: B126 pack

Post by Michael Watterson » Sat Oct 13, 2012 11:13 am

Avoid Kodak, even the Zinc Carbon.
Some are fatter than they should be, yes.
Alkaline use 6 x AAA cells inside, so sometimes are a little fatter, most are OK. Aldi ones fit.
Zinc Carbon use 6 x stacked "biscuits" inside and should work. No point to Zinc Chloride for this application.
Polariod and Sony Zinc Carbon fit
Image
The narrower width there is tightest dimension, the three layers lying on top of each other should be a tight fit in the outer box. The height isn't a problem nor the direction of packs plugging into each other.

Generally Alkaline are not good value for PP3 as they are 6 x AAA so don't fill the case so well.
At 8.5mA HT when battery fresh
Zinc Carbon about 50 to 60 Hours
Alkaline about 65 to 75 hours

Very approximate times.

Since Alkaline PP3 are x2 to x5 price of Zinc Carbon PP3 ...

 
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Alkaline vs Zinc Carbon

Post by Michael Watterson » Sat Oct 13, 2012 11:37 am

Generally Alkaline are not good value for PP3 as they are 6 x AAA so don't fill the case so well.
At 8.5mA HT when battery fresh
Zinc Carbon about 50 to 60 Hours
Alkaline about 65 to 75 hours

Very approximate times.

Since Alkaline PP3 are x2 to x5 price of Zinc Carbon PP3 ...

I think the original layer packs about 70 hours based on volume and also likely the AD35 lasted about 70 Hours on 250mA filaments (Likely 18000mAH). So after Dx96 tubes (1953 and later) the LT packs would have lasted about x2 the HT packs.

This made people suspicious of Ever Ready Radio sets using combi packs like B141 and B136, but the B103 and B114 are "balanced" for 250mA LT and the B136, B137 and B141 "balanced" for 125mA LT. Of course the LT and HT won't perfectly run out at same time, but close enough that people were not getting cheated. With separate packs, especially with Dx96 valves from 1953, people would not easily know which pack to replace. You can't see the filaments glow easily anyway.

The AD38 series pack (usually only mains /battery sets) was about 2500mAH (5 x B cells in series) so only about 50 hours or less with 50mA series and about 100 hours on Dx96 valves. The Alkaline AA are thus a good choice as they are about 2500mAH. Real B cells x3 exist inside 1289 (3R12 MN1203 312G etc) still available, especially on mainland Europe.


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