How long can a PP9 last ?

[beam me up schottky]

In what I loosely call my, ahem, study I have the radio that I seem to use the most. Namely a Ferguson Transistor 7, bought off ebay because I liked the unusual case, which was and remains broken in the top right corner as I haven't had the chance to strip and repair it. This is mainly because the radio works so well !
Now the point, it came with a PP9 already in place, which I presume had already been used when I bought the radio. This was 7 or 8 months ago and it's still going strong ! This is with hours of use most days !
The PP9 in question is a Panasonic, special power, zinc carbon !
That seems to be an amazing battery life in my experience, other opinions please ?

[tiv48]

i dont know but i have a grundig music boy its had the same battery for 3 years its used about 15/20 mins a day and still going strong . battery is a ray o vac high power
rob t

[Steve_P]

I can beat that. I have a Roberts RIC1 here and it has a battery in it that I bought before I had the stroke. Still works!!

Cheers,

Steve P.

[Duke Nukem]

Funny enough, I've just been tinkering with a Fidelity and two RIC1's, they take around 30mA. According to CPC the Ever Ready battery I'm using is 4.4AH, so that equates to maybe 130Hrs usage, though whilst fixing one of the RIC1's I discovered it still works extremely well at 4V (!) so perhaps can extract even more from a PP9 than other sets.

When I update the website, I'll post a picture of the PP9 that came out of one of the radios - that should hopefully persuade people to remove the battery if not using for an extended period, jeez what a mess !

TTFN,
Jon

PS : If anyone spreads the word that I've been tinkering with tr*ns*st*rs I'll sue ! I have a reputation to maintain ... ;-)

[Paula A]

My mother had a Demon .. it used to need a new PP3 every 2 years.. it was used 2 hours every morning without fail.

[fido]

I gave up with my Hacker as it consumed the first pair of batteries at an alarming rate. At least I finally have a cordless mouse that is light on batteries. It's a Technika but this one has a sort of sleep mode so you have to left click to turn it on. There is also a slide switch underneath but I don't bother to turn it off there.

[Mark Hennessy]

I got nearly a year from a pair of PP9s in a Hacker Sovereign II, used daily in the kitchen for a couple hours at least. Same story with the VHF Herald in the bedroom - not bad given that I often fall asleep listening to it and wake up in the early hours to find it still playing...

With any transistor set, you really must check the quiescent current and set it up according to the instructions - things drift with age, and it's not unusual to find that the current is wrong... As a guide, anything over ~30mA for an FM set at minimum volume needs investigation (starting with finding the actual answer from the manufacturers information, just in case it's an usual one)

Examples from the Hacker world (what else is there ). Where two figures are given, it's AM followed by FM:

• RP18 Sovereign I: 14mA/18mA
  
• RP25 Sovereign II: 18mA/21mA
  
• RP35 Herald: 18mA
  
• RP37 VHF Herald: 21mA
  
• RP71 Harrier (FM only): 34mA
  
• RP72 Sovereign III: 20-22mA/22-25mA *
  
• RP73 Autocrat (AM only): 20-22mA
  
• RP76 Silver Knight (FM only): 25-30mA Mono, 50-56mA Stereo *
  

* These use D cells, not PP9s, but included for interest. And note that a faulty microswitch on a DIN socket can cause the Silver Knight to switch to Stereo mode needlessly and double the current consumption (stereo is only available on the DIN socket, so decoder should only be powered when the DIN socket is in use)

Cheers,

Mark

[Ian E G7OLT]

I gave up with my Hacker as it consumed the first pair of batteries at an alarming rate. .

Which model Hacker? Do you know what the current draw is? Most of the 18V sets pull 20 to 24mA quiescent depending on which waveband is selected. I usually get a year or so from a pair of PP9s in an RP25B Sovereign II. Maybe yours has a fault.

[Mark Hennessy]

Another strategy is to make some PP9 to PP3 adaptor leads by soldering on PP9 snaps to a PP3 lead. RS sell the PP9 snaps (464-754) - they look a little modern, but are better than nothing and are fine for an adaptor lead... Plus, I have made up some leads with 4mm plugs on one end, these battery snaps on the other, which plug into my bench power supply and connect straight onto the radios battery snaps.

And another thing (I'll shut up in a minute - honest :s) - you can take apart dead PP9s and put a PP3 inside, or get a battery holder that will take 6 AAs that will fit into the box. The modern plastic cased PP9s are best for this. That said, a 4Ah PP9 will probably last longer - AA cells average typically half that...

Mark

[AlanBeckett]

I put seven rechargable AAs into an old battery case with a limiting resistor and filled it up with wax. It lasts for ages.
Alan