Batteries for Gossen Lunasix 3

Discussion in 'Medium Format' started by kenneth_amorino, Apr 23, 2007.

  1. I am very confused about replacing the batteries on an old Gossen Lunasix 3 light meter. I am
    wondering if I use silver oxide batteries are they a direct replacement for the mercury oxide batteries or
    do I need the battery adapter. Also are the Wein aircell batteries a direct replacement or, again, do I
    need the adapter. Or is the adapter just for alkaline cells. Are thoughts or knowledge on this subject
    would help. Thank you in adavnce. Ken
  2. You could use silver Oxide but they are about 1.5v while mercury is about 1.35v. Now, the difference is small but you meter may be off a little bit. This is no problem if you know it and you can adjust it. On the other hand, there are adaptors available to get the voltage right or could another type op battery that gives 1.35v and use an O-ring to make it fit. Maybe some other members have better or more handy ideas.
  3. There is an adapter for the LunaPro/LunaSix 3 that fits in the battery compartment and holds 2 SR-44 cells. Gives the correct voltage, with it the meter does not have to be recalibrated. Used to cost around $18, I believe that these days it costs closer to $40. B&H sells 'em.

    Kenneth, grit your teeth and buy one.
  4. Frans de Gruijter sells adapters that hold one SR-44 cell, and they work like a charm. At current exchange rates, the cost for two would be about $40 (including shipping). An advantage over an adapter that holds 2 SR-44 cells is that you can also use these guys in devices that need just a single battery.
  5. Does anyone know anything about the Wein air cell 1.35V batteries?
  6. They can be used but they have the tendency to be depleted very fast, so be prepared to have some spares with you. But they are of course cheap as dirt.
  7. Sorry but I'd start shopping for a new meter that takes a AA.Anything that takes a PX625 is a relic.I have a stash of Varta merc cells for my elderly Nikon metered finders but wouldn't bother for a meter.Used Sekonic models like the 308, 318, and 328 aren't ruinously pricey.Try the silver oxides but what's the point if the meter's inaccurate?
  8. Things that take old batteries can still be (and often are) excellent machines. The suggestion they are not, just because they have existed for a while already, using the type of battery they take as a measure, is ridiculous.
  9. See

    or google for mercury battery constant voltage. An alkaline battery's voltage varies too much. A silver battery varies less than alkaline, more than mercury, and it is (as UG above points out) not the right voltage, quite.
    Good luck.
  10. As Dan pointed out: there are adaptres that allow use of still available batteries without any voltage problems. You can get such an adapter for the Lunasix from Gossen themselves.
  11. Uncle Goose, have you priced Wein cells? The last time I did they were outrageously expensive.

    Richard, I said it once and it pains me to say it again. Gossen's adapter for putting 2xSR44 in a LunaSix puts out the right voltage. It is not just a shell that holds the cells in place.
  12. according to the chart here
    you see the silver oxide battery is at one voltage for the first 20% of its life (maybe 1.65v) then drops so that between 30-90% it is at 1.55v, then drops off to 1.2v, (then 0)

    The mercury cell is pretty much constant from 5% to 80% at 1.3v or so.
    NiCad is even flatter, at 1.2v.

    There are other characteristics of batteries that matter in applications, but if finding most-constant-voltage (under very low drain) is the requirement, then silver is not as good as mercury, even if the voltage is dropped slightly. If the circuitry in the meter or other device makes the exactness and the constantness of the battery voltage irrelevant, that would be more of a comfort.

    (Sorry to pain you!)
  13. I've used the Wein cells in a Lunapro and they do give accurate readings. I now use the Gossen adapter and two SR 44's as mentioned. Adapters are the best longterm solution, in my opinion. Here's the link to the Gossen adapter at B&H:
  14. Richard,<br><br>Don't read about batteries and adapters. Try them.<br>There is no problem.
  15. Ken, life is too short. Sell your Lunasix on the auction site for $50. Then buy a Luna-pro SBC with the same $50-- it has a silicon photocell, and it takes 9V batteries.
  16. Forget the adapter, just stick some alkaline 625 equivalents in the meter.

    IME the battery voltage makes SOME but not a very significant difference to the meter reading. Use the battery check, and you'll see that the needle deflects about half a divison past the red BC mark. That's the error that you'll get. So just knock half-a-stop off the readings.
  17. Sorry, Q.G., but what's ridiculous about opting for accuracy? There are tons of posts in the PN archives about mercury battery replacements--nearly all of them pricey, awkward, or plain Mickey Mouse.I don't think the Gossen "adapters" do anything about voltage--or do they? I bought the spendy MR9 adapters for several elderly cameras that swallowed PX625s but now find the cameras don't get much use.My only point is that vintage gear can have serious operational issues--apart from battery woes--that make them "iffy" choices for anything but fun. Meters are fragile and don't age well. I'd rather spend a few bucks for dependable accuracy and linearity--my only point--than screw around with puzzling out compensation formulae for voltage anomalies.
  18. Gary,<br><br>What is ridiculous is this (repeated) suggestion that these meters are not accurate. They are.<br>They are accurate when using adapters and available batteries too.<br>It is ridiculous to suggest that because other meters take other batteries, they are more acurate.
  19. Oh and...<br><br>Yes, of course these adapters do more than just adjust for different battery sizes! Using these thingies the problem is solved. Really, and completely solved.
  20. Fine but you'll admit there's a far higher probability of inaccuracy with and old meter than a new one. Unless or until film and processing are free, I'd rather spend the extra $$$ on consistency than surprises at the lab. Have fun.
  21. Fine but you'll admit there's a far higher probability of inaccuracy with and old meter than a new one. Unless or until film and processing are free, I'd rather spend the extra $$$ on consistency than on surprises at the lab. Have fun.
  22. Gary, all used meters are presumed inaccurate until proven otherwise. There's a big difference between working at all and giving the right answer.

    About the Gossen adapter for 2xSR44. It performs as claimed. And the advice my LunaPro (= LunaSix 3) with the adapter gives yields good Ektachromes. Yes, I had the meter overhauled by Bogen. But as I said all old meters need to be overhauled before they can be used.

    If you want to be badly insecure about used meters that's your business, but please don't try to spread your insecurity around.
  23. Lots of misinformation here, which is unfortunate, because some novice searching on "light meter" is going to stumble across this thread.

    We're in the 21st century, folks. It is absolutely laughable to recommend Rube Goldberg workarounds to keep obsolete CdS meters going. To get a reliable silicon meter, you're looking at maybe a hundred bucks, give or take. How much is your time worth?
  24. The misinformation here is that newer meters are better, and that it takes a lot of effort to keep older meters going.<br>They aren't, and it doesn't.
  25. This seems to be decaying into some sort of doctrinal squabble. Newbies shouldn't be encouraged to chase crusty old Westons or Gossens.Working meters aren't necessarily accurate meters.If owning one of these relics empowers you or bestows some sort of nobility on you--great! Insecurity? Sure, I worry about correct exposure but worry a lot less about it when I'm not using an elderly meter. I'll take a new or newish Sekonic meter any day, thank you. Cheers!
  26. Gary, a Master V overhauled by Quality Light Metric costs less than a new Sekonic or Gossen. Same goes for a LunaSix 3 overhauled by Bogen.

    I'd never advise anyone to grab an old meter that seems to work and take its advice seriously. They're all off calibration until proven otherwise.

    The issue, at least for me, isn't doctrine, it is total cash outlay.
  27. If you get the meter cheap enough, open it up and add (or have an electronic hobbyist friend add) a series Schottky diode (less than a buck at Digikey) to the positive battery lead (with the cathode band connected to the meter and the other lead connected to the battery +). The forward voltage drop is 0.4 volts, exactly what's needed to compensate for the change in battery voltage between 2 mercury cells and two silver oxide cells.
    According to some sites on the web, the LunaSix/LunaPro CDS meters have four or five adjustment pots inside, which can be tweaked to compensate for the different cell voltage. The diode sounds easier to me, but then I'm an EE!

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