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rca: Personal; RCA BP10: A and B batteries?

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Forum » Radios and other type of sets (Physics) etc. » MODELS DISPLAYED » rca: Personal; RCA BP10: A and B batteries?
           
Michele Denber
Michele Denber
 
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27.Feb.09 22:43

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Hello dear Collectors.  I just got an RCA BP-10.  This radio uses one A and one B battery.  I suppose I can substitue a C or D cell for the A battery, but the B battery has me stumped.  The B battery is 67.5 V.  I've checked the web and Ebay and found nothing.  At worst I could empty out the guts of the dead battery and replace it with something new - but what?  Has anyone done this before?  What did you use?  Thanks.

Und auf Deutsch: Ich suche ein B batterie fur ein RCA BP-10 aber kann das nicht finden.  Wissen jemand wo man das kaufen konnen?  Oder ist es basteln etwas moeglich?  Danke sehr.

Bernhard Nagel
Bernhard Nagel
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27.Feb.09 23:44

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Dear Michele,

there are two ways in replacing the no longer produced high voltage batteries for (portable) tube radios like your RCA BP10. The easiest way is: empty out the dead battery and refill it with the correct number of 9 Volts batteries (MN1604). These are connected simply in series, for 67.5 volts you need 7-8 batteries. Since radios such as the RCA BP10 has no more than 10-12 mA total power consumption, it can thus operate 20-40 hours. But you should be aware with the new high voltage battery B! You can easily submit some amperes of current if it is accidentally shorted. A fuse of 100 mA should be inserted between the battery and radio to avoid a fire hazard or explosion.

The second option is a voltage converter to use. It runs with 2 C cells and generates 67.5 or 75 Volts. These replacement batteries are also sometimes offered on ebay, item number 360133485153 shows some nice examples, it comes from Austria. Also, the self-build of a voltage converter is possible, there are some interesting articles in the RMorg forum regarding this, unfortunately only in German language. Using the terms Anodenbatterie Ersatz in SEARCH shows some hits, like this and that.

Hope, this will help a little!

Bernhard

Roy Johnson
 
 
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27.Feb.09 23:39

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Hello Michele,

Most folks use the 9v PP9 style batteries connected in series. 

My preference is for the circular Lithium cells that last even longer with a shelf life of perhaps 10+ years. I put these in a plastic tube such as that used for drainage.  It is sufficient to add plastic foam pieces at the end and tape over to maintain contacts between the cells and wires for the connections.   Like a voltaic pile!

Happy building!

Regards,

Roy

Thomas Albrecht
Thomas Albrecht
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27.Feb.09 23:44

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Hi Michele,

You have a few different options here:

1.  Replace the 67.5 volt B battery with eight 9-volt batteries in series.  This is commonly done today and is the easiest option.  Don't worry about the voltage being a little higher than 67.5 volts; it will work fine.

2.  Fancier version of the above:  Build the eight 9 volt batteries into the shell of an old 67.5 volt battery.  Takes a bit of mechanical innovation, but you will likely figure out a way to do that.  If you don't have an old battery available, with an internet search you will likely find a scan of the cardboard shell of an old B battery (for example, Eveready type 467) that you can print out and wrap around a new battery pack you make in a cardboad or wooden enclosure of the right physical size.  You might also find that you can fit sixteen 9 volt batteries inside, with series-parallel wiring, which will give you twice the battery life.

3.  Build an AC-powered external power supply to serve as a battery eliminator.  I've done some designs for power supplies to work with typical battery tube radios and can post if desired.

Best regards,

Tom

Bill Morris
Bill Morris
 
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28.Feb.09 00:21

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Michelle, feel free to contact me at batterymaker at gmail dot com.  I'm reworking a solution for the battery you need--it's called a 467.

 

Bill

 

Michele Denber
Michele Denber
 
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28.Feb.09 01:36

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Thanks 

Wow, thank you so much to everyone for the prompt replies.  Fortunately, the radio came with a B battery in it, although it is obviously long since dead.  Fortunately, it did not leak and the carton looks great.  (It is a Burgess battery).  I certainly thought of emptying this battery and putting 9 V. batteries in series inside, but I didn't know if there might be some reason why that would not work.

Thanks to Bernhard for suggesting using a DC-DC converter.  I like that idea and had not thought of it.  Thanks to Roy for suggesting lithium cells.  That's a great idea since I don't really plan to be running this radio often once I restore it.  Thanks also to Thomas for suggesting a series-parallel arrangement.  If they'll fit, I might just do that.  And thanks to Bill for the contact.  It looks like I now have a plan to proceed.

Konrad Birkner † 12.08.2014
Konrad Birkner † 12.08.2014
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28.Feb.09 11:41

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a #467 battery  is correct. Available from Antique Electronic Supply (AES) in Tempe,  AZ.

see tubesandmore.com.

Good luck
KoBi

Michele Denber
Michele Denber
 
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28.Feb.09 21:43

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Yes, when you add up the cost of individual 9 v. cells and the time and effort involved, I might as well just buy one from AES.  I have dealt with them often and can highly recommend them.  They have lots of tubes and capacitors we need all the time, and their shipping is super fast.  I don't know why I didn't think of that.  Thanks!

Michael Watterson
 
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16.Oct.11 14:10

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The lithium CR2032 coin cells are not great above 1mA or 2mA discharge current so for a 90V pack I used 6 x stacks in parallel via 6 x 1N4148 diodes in cardboard tubes. Total  about 1200 mAH compared to 180mAH for a stack of Alkaline PP3 9V cells.

Since voltage is 3.2V down to 2.75V you don't need as many as you think (Carbon Zinc is 1.6V down to 0.9V per cell).

So though "90V" might suggest 30 coins per stack and 67V  a stack of 22 coins, actually 25 is fine for a 90V set (though I used 26 x 6 coins). no more than 30

67V set 18 per stack/tube will work, no more than 22

For a 48V set 13 or 14  coins per stack is fine, no more than 16.

The 48V, 67 and 90V are very much nominal voltages and even if we take 1.1V rather than the industry spec of today of 0.9V for exhusted cell

90V -> 66V (60x Zinc Carbon cells)

67 -> 49.5V (45x Zinc Carbon cells)

48 -> 35.2 (32x Zinc Carbon cells).

I bought CR2032 at SEVEN Euro cents each including postage from Hong Kong.

(20mm diameter, 3.2mm thick, 200mAH to 270mAH depending on maker/quality)

 

  
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