Just wondering if anybody here is knowledgeable on the 4v virbrator AWA 508M radio. I have one of each in the bakelite and timber variants and they work well. I interested to know why they used a 4volt battery instead of the more common 6 volt type which were readily available. Were these batteries a special or common back in the day and were here any other manufacturers of these 4volt radios? Thanks

2, 4 and 6 volt accumulators were available. I guess price and space occupied would have been considerations:

https://www.vintage-radio.net/forum/attachment.php?attachmentid=110026&d=1435435538

Accumulators. Wow! Memory lane stuff there GTC.

I first heard the term from my dad when I was a kid. The "accumulator" in his old Vanguard (which he bought second hand) lasted several
decades. The closest I've come to such battery longevity in cars is seven years.

BringBackTheAccumulator I say!

In Industry and farms battery banks were made up of 2 volt cells.
Probably the radios were in a 32 volt system but connected to 2 cells only.
Car batteries were 3 x 2 volt cells built into one case.
Gosh this ages me..........
In a test room I worked in we had a bank of 2 volters giving up to 48 volt and a "Tungar" battery charger (big fat valve) to series charge the lot. I could run 32 volt farm motors, test generators and motor start enignes from the one bank.
One of my jobs was to test each cell with a handheld device that was basically a discharge resistor with a voltmeter.
I still have that in my "museum" section somewhere.
Each cell had to be topped with water and if it could not hold the test load, seperately charge it to bring it up to specific gravity.
Sometimes add water or acid to suit. Yes they were pure lead plates and if looked after were immortal.

This was about 200 years ago so it seems!

Fred.

Fred I remember my days of telecom the battery rooms at the exchanges had 2 volt cells x 25 in lots of 2. They would easily weigh 50 kilos each. When they were decommissioned telecom would sell them to the solar shops for $2.00 each. Boy did I hate removing those lol.

The Paton VCT here has a 6V Vibrator PSU as at the time a lot of vehicles (as noted) used 6V and later with overwall connections on the 12V Battery's It could still be used offsite. The tractor here is still 6V. and uses a standard B3. Interesting that with the change in technology & construction the most recent one has more capacity than the previous one and considerably more than those, when it was made (1951)

4V is easy to do with one to 2 diodes. Depending on the situation it is desirable to have a load on the output side or is surges to source voltage.

The biggest issue with the older batteries was "shedding" which modern seperators tend to reduce. SLA batteries (automobile) do not like being run flat. I was told 15 times & and you lost 25% of capacity. However, for caravan & caravan work I told the neighbours to get rid of the car batteries & replace with proper motive storage (deep cycle) types when they died. The difference was quickly realised.

Beware some SLA batteries claim "deep cycle" and are not really. To me if its got CCA on it its an SLA.

Marc

Thanks Guys for the info, It just seems a strange voltage when 6volt was so common. I've strolled through trove and although there were other 4volt radios made (the Astor 500 was one) the AWA 507M, 508M seemed to rule the roost. Just not sure why they opted for 4 volt operation. Perhaps the batteries were smaller and easier to conceal in a cupboard etc.

Also to consider with wet batteries, was that there were individual 2V cells for filaments. Their cases had handles.

Marc

I wonder if 4 volt accumulators were used because 4x8=32, so 8 of these could be used for storage in a 32V farm system. If so they would be common on a 36V farm. 6V would not suit the arithmetic quite so well.

STC830: sounds feasible.