UK battery suppiles

I still have the Pye "Jewel Box" mains/battery portable MW/LW radio my parents bought around 1955.The last time I tried it a dozen or years ago it still worked on mains, but I've just tried it again and it's silent. There seems to be 70V HT, which is a bit surprising given the age of the capacitors - especially the electrolytics. However, it seems that it should be 90V. The valves also don't get warm; I can't see any filaments glowing, but they are ok using an ohmmeter.

On battery, it used a 90V B126 battery for HT and a 7.5V AD38 battery for the valve heaters (I believe the four valves have their heaters in series).

It's identical to the one shown here:

Also see P131MBQ at

Circuit diagram available from Elektrotanya at

Pedant mode on...

The CO /detector/ could have died, and its being dead was picked up by the electronic circuit which then lets you know by the screech that the detector no longer worked.

Pedant mode off...

Most common 'cheap' brand here is Panasonic - through 'Dollar' store franchises. No signs of supply chain disturbances,lately. Alcaline PP9s for handheld meters and smoke detectors still demand them annually - though there's a drift towards multiple AA or AAAs, which have nimh rechargeable equivalents.

Vanity/seasonal lighting, remote controls/doorbells keyfobs/watches the primary consumer uses of cylindrical formats.

Single 3V9 Li-Ion w 5V USB charging interface is pretty much the cheapest solution now,with simple output converters for 9, 6, 5V pre-installed. Where physically practical, I'll retrofit.

I hate primsry batteries, but am learning to live with rechargeables.

All from China.

RL

It really isn't worth wasting pedantry on John Larkin. I shouldn't have bothered myself.

The user doesn't care why the detector has decided that it is faulty and needs to attract the user's attention. If they could buy a new battery or a new carbon monoxide detector, it might be worth telling them, but cheap consumer devices are cheap because they eschew any unnecessary complication. It's simpler and more profitable to get the user to buy a replacement unit rather than a replacement sensor or a replacement battery.

Memories. Our Family had something similar - a valve portable with a dual battery HV for valves (or tubes!) and LV for the heaters. My introduction to "electronics" (at something like 11 years old) was assembling the mains PSU kit by dad bought 'cos the batteries were ridulously expressive. It worked but I wouldn't want anyone examining the soldering. I used a plumber's iron heated on the gas ring with plumbers flux and solder. My uncle, a plumber, helped out :-)

Hey don't laugh, it got me interested in electronics.

A carbon-zinc PP9 has about 4Ah capacity so is probably a bit more than one made from 6 x alkaline AAs that are only 2-3Ah. Although the price of PP9's these days means that AAs would be much cheaper to run and could be rechargeable.

When I was a teenager PP9s were the main power supply for my experiments

- I would get through about one per year.

Many transistor radios in the UK at that time used them.

^^^^^^^^^^ <--- expensive!!!

no spell checkers or AI involved - just a fuddled brain.

Yup. My stock of tubes all came from the junk yard or from radios left out for trash pickup. As a kid, I couldn't believe people would throw out old tvs and radios. We had two radio/tv repair shops in town - why throw it out when you could get it repaired? I scrounged everything fro the discards - R's C's L's chassis cabinets etc. Even line cords! Had no money - what I earned from the paper route and odd jobs went into the college fund. But I had plenty of electronic junk to play with. :-) Those "public" tube testers were gold to me!

Wonderful.

Jim

But we are in danger of getting into Monty Python four yorkshire men warm grit territory :-)

I had a huge old iron about the size of a baseball bat. One day I dropped a giant blob of solder onto my bare foot.

The next step was to get a Wen soldering gun. Do people still use soldering guns?

Metcals are wonderful.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

Yikes.

This sort of prototype can be documented and archived and fired up later if required. And handed off to someone else to temperature test or whatever.

Does your power fail often? For long?

We lost power for a day or so, in the 1989 earthquake. All the neighbors had an ice cream exchange party, thinking it would all melt.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

A long time ago I knew a battery manufacturing plant designer who was familiar with the operations of most of the manufacturers world-wide. His advice was that Panasonic/Matsushita had better quality than any of the others. He was specifically commenting on rechargeables, but the quality culture was probably the same for primary cells.

John

Open up a Panasonic PP9 alcaline, and you'll see 6 individual AAAA cells, spot-welded, inside the housing. My gob was suitably smacked, the first time I saw this.

Carbon PP9s are the usual stacked mud.

RL

What were you expecting to see? I can't think of any metallic-chemical combo that's able to generate 9V in a single cell.

A PP9 is not made that way - you mean a PP3 (the much smaller one), a PP9 is app 80 x 65 x 52mm.

This page has a list of the different PPxx style batteries.

Some of the ebay sellers are offering 12x AA converters which give more runtime. I assume they're a 6S2P pack - putting two alkaline AAs in parallel sounds... questionable?

I suppose if they came out of the same pack they might be roughly balanced and follow each other down the discharge curve, but at the bottom of the discharge curve perhaps one's terminal voltage is going to drop off faster than the other, resulting in one trying to charge the other?

If you were doing this with NiMH then it might be a better plan, and similar capacity (~3Ah) NiMH are available. Although you might want 7S or 8S to get the more appropriate pack voltage.

Theo

I don't see any problems.

I generally buy mine on Amazon (or Rapid) depending on who is cheaper and in 40x blocks. Where I can I use rechargeables but some LCD devices won't work at the lower terminal voltage of NiMH/NiCad.

Aldi & Lidl still have most sorts available. They sometimes have pretty good rechargeables (better value when they are discounted at end of line). Poundland often has rubbish grade Kodak AA batteries at silly prices which are good enough for some near throw away applications.

I suggest you try a larger supermarket. The only battery I think are discontinued are the 45v & ~90v ones intended for portable valve radios.

My preference is for Panasonic or Amazon's own brand at the moment. I suspect the cheap availability online has crippled sales through supermarket. They are a handy make weight for reaching free delivery on smaller orders (to any of Amazon, Rapid or RS).

I avoid Duracell like the plague now - they are the only batteries that have ever leaked in my gear and done damage.

Slip of the tongue, I guess; was refering to PP3.

Seeing six cylindrical cells used to build one gives me the economical justification jitters.Plastic and mud packs, I'm just ignorant enough to understand.

Had never heard a PP designation used, till I went to the UK in late

Learn something every day.

RL