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Hung Chang os615s Battery

Discussion in 'General Electronics Chat' started by Dudley, Nov 19, 2016.

  1. Dudley

    Dudley New Member

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    I recently purchased a Hung Chang OS615s and it came without it's internal battery. Can anybody tell me the spec for a new battery for the above please?
     
  2. spec

    spec Well-Known Member Most Helpful Member

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    Hi Dudley,

    welcome to ETO,

    Which part of Ireland are you at? If you put it next to 'Location' on your user page it will display in the box at the left of your posts. Not only is it interesting to know where members are from, but it also helps with answers.:)

    spec
     
    Last edited: Nov 19, 2016
  3. spec

    spec Well-Known Member Most Helpful Member

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    Hi again Dudley- you don't give much away do you!

    So a Hang Chang OS615S is an oscilloscope, presumably mains powered from what I can tell. The OS615S is pretty old, from the 1980s I think, and the service manual is not available from what I can tell.

    What is the battery that you ask about like. Is it a small button cell. Is it a large battery used to power the OS615S? Can you post some images showing where the battery fits. That would help to determine what size the battery is. Are there any markings on the OS615S indicating what the battery voltage is?

    spec
     
  4. dave

    Dave New Member

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  5. Dudley

    Dudley New Member

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    Sorry, yes it's an oscilloscope. Designed to work off 120v or 240v a.c., external d.c. supply 11-30v or the internal battery for which the charging voltage is 22.3v the size of the battery holder pictured is 11 x 9 cms approx. and the compartment is also pictured. also is pictured the back panel. I have found some figures which suggest June 1989. The scope is in full working order and I'm just one of these people who thinks if it should have a battery it would be nice to have it complete. I have tried uploading the jpeg files but it don't seem to work
     
  6. spec

    spec Well-Known Member Most Helpful Member

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    Thanks for the information Dudley- that is a great help.:)

    Good news that the scope is working OK.

    You probably can't upload images because you are new to ETO. If you contact one of the ETO moderators they may be able to help. There is also a setting in your browser which may prevent you from searching your directories to find an image. If you get this problem, just post and I will post a possible cure.

    spec
     
    Last edited: Nov 19, 2016
  7. spec

    spec Well-Known Member Most Helpful Member

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    About the scope battery, is it a rechargeable type as far as you know?

    Because the battery is most likely a special type, as I see it, you have only one practical option and that is to reverse engineer a replacement battery pack.

    The good news is that battery performance has improved dramatically since the 1980s so you should end up with a much longer battery duration. The battery can also be much lighter, if you go for a Lithium Ion battery pack, assuming the original battery was Lead/acid or NiCad.

    22.3V can be achieved, close enough, by six of LiIon cells in series to give a nominal voltage of 6 * 3.6V = 21.6V.

    The total cost of the battery pack and charging/protection circuits would probably be around £30UK as a guide.

    spec
     
    Last edited: Nov 19, 2016
  8. Dudley

    Dudley New Member

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    Yes it has a charging circuit so presumably protection as it has a charge indicator to tell when battery is being charged. the last time I purchased some of these batteries I could not get one end of the batt to solder, any suggestions would be gratefully received?
     
  9. spec

    spec Well-Known Member Most Helpful Member

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    Can you describe what batteries you are talking about?

    Some batteries are available with tags that you can solder to. Alternatively you can weld tags to a battery and kits are available on ebay. I used to know how the welding was done but have forgotten.

    The other method is to use battery holders, like this: http://www.ebay.co.uk/itm/like/2816...=9045657&device=c&campaignid=661151662&crdt=0

    spec
     
  10. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    • Informative Informative x 1
  11. spec

    spec Well-Known Member Most Helpful Member

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  12. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    Li-Ion requires special charging circuitry. You can substitute Ni-MH for Ni-Cd without problems. I have done this for cordless phones. NiCd's are getting scarce. Lithium didn't likely exist back then.

    Digi-key and other electronics suppliers sell packs of various cell configurations with the heat shrink over wrap. If you can find the right geometry, generally you solder the connector from the old pack (assuming wire leads).

    Making the pack yourself requires you to weld the tabs on the batteries. You can also buy batteries with tabs, but sometimes there isn't room to solder them too.

    I have a Tek scope that uses batteries and that pack is very unusual, but still made if you really hunt.

    Yep.
     
    Last edited: Nov 19, 2016
  13. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    You may be new and attachment uploading may be disabled for a day or so. Unknown what the criteria is.

    You can also try disabling the "Flash uploader" under "Preferences" when you click you handle on the top right of the page.

    And for some reason on some platforms the case of the extension has to match. i.e. jpg vs JPG. The accepted extensions are listed.
     
  14. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    Volume not area. You have a missing dimension. I'm, sort, of thinking 2 X 12 V or 1 x 24 V primarily based on the era and the operating voltage.
     
  15. Dudley

    Dudley New Member

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    Thanks to everybody for your advice will give the Li-ion batteries a try. In what way are the charging circuits different
     
  16. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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  17. Tony Stewart

    Tony Stewart Well-Known Member Most Helpful Member

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    LiPo's are fast charged at 4.2V per cell with a float voltage of 3.7 after current declines by 80% . I suggest the charger should be limited to 3.7V per cell for simplicity. With a >= 125W soldering gun and tungsten needle points instead of copper loop , you may be able to weld to the steel shim with 100A , but spring contact sockets may suffice.
     
  18. Dudley

    Dudley New Member

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    If I charge 6 li-ion cells Which I believe would be 22.2v with a constant 18v would that be ok do you think?
     
  19. Les Jones

    Les Jones Well-Known Member

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    Hi Dudley,
    Charging lithium ion cells is not as simple as charging Ni Mh, Ni cd or lead acid batteries. The charging of each individual cell has to be controlled. so it is not just a simple matter of connecting them in series. If you take a laptop battery apart you will find quite a lot of electronics inside it to control the charging as well as the cells.

    Les.
     
  20. Dudley

    Dudley New Member

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    I appreciate all the help but we seem to have lost sight of the objective, which is, the oscilloscope was designed to run on an internal battery which it automatically charges and this is ideally what I would like to replace.
     
  21. spec

    spec Well-Known Member Most Helpful Member

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    Not quite sure what you are saying there. For a simple charge/discharge regime with six Lithium Ion (LiIon) cells in series you need 4 * 6 =24V constant voltage with a current limit of 1 * C say (C is the the battery capacity, say 3.4 A/H). Any lower current limit would also be suitable.

    A conservative cutoff voltage would be 6 * 3 = 18V.

    To make a suitable LiIon battery pack you would connect six LiIon cells in series and also connect a battery balancing and protection circuit to the six cells in series. The parts to do this are reasonably cheap and widely available.

    How to connect the batteries in series? There are a few practical options:
    (1) Buy batteries with leads attached
    (2) Ask the battery vendor to attach the leads for you
    (3) Use battery holders (as previously mentioned).

    In my view (3) is by far the simplest approach, provided, of course, that you have room for the battery holders (they are not very big): http://www.ebay.co.uk/itm/Batteries...721376?hash=item1a1c3a2160:g:c5kAAOSw8w1X4NGD

    Here is a link for a 6 cell LiIon battery balancer, protector and cut-off circuit: http://www.ebay.co.uk/itm/6S-Cell-1...368332?hash=item3d2537070c:g:bl4AAOSwGtRX0uW1

    Don't worry about LiIon batteries. They are normally trouble free and simple to use. They are employed all over the place from mobile phones, thru cameras, thru power tools, through electric wheel chairs, to electric vehicles, typified by Tesla cars, which use LiIon 18650 cells and a conservative charge/cut-off regime.:) The reason for LiIon batteries wide use is that no other commonly available battery can match them. They have around 2.5x the energy volume and x 0.33 the weight for a given energy storage. LiIon batteries also have the best energy retention of all commonly available high-power rechargeable batteries. They also have a relatively stable voltage and low internal resistance throughout their discharge cycle and you can use most of the energy stored, within a particular regime. The other major advantage of LiIon batteries is that they have a charging efficiency approaching 100% compared to 50% for some other battery types. This means faster charging and less wasted energy.

    This is not a high current drain application, so LiPo batteries are not necessary. Genuine LiPo batteries have a lower nominal voltage of 3.4V, which will complicate the issue anyway.

    Just a word of caution, only use mainline manufacturer's batteries (Panasonic, Sanyo, Samsung, LG, Sony) from a a reliable source. Don't be tempted to buy batteries that appear to be cheap and high performance- they are a rip off. This is the supplier I would recommend to get decent batteries at a reasonable price: http://batteriesplus.co.uk/acatalog/copy_of_Lithium_Ion__Li-Ion___3.7V_Batteries-1.html

    The only problem I can see with this project is the volume available to house the battery pack. Can you please specify this?

    spec
     
    Last edited: Nov 19, 2016

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