1/3AA Lithium battery

[Gareth Magennis]

Hi,

I am having difficulty finding a 1/3AA Lithium battery.

It is for this application, any substitute has to fit in pretty much the
same space as 1/3AA, there is no spare room.
http://wolzow.mindworks.ee/analog/jx-10-m-16c.htm


I did find rechargeable NiMH types, but I don't think they will keep their
charge for the years expected of a memory backup battery?


Perhaps I could utilise watch type button cells, if I could find a holder
for them.


Cheers,


Gareth.

[pf...@aol.com]

On Friday, March 10, 2017 at 1:13:57 PM UTC-5, Gareth Magennis wrote:
> Hi,
>
> I am having difficulty finding a 1/3AA Lithium battery.
>
> It is for this application, any substitute has to fit in pretty much the
> same space as 1/3AA, there is no spare room.
> http://wolzow.mindworks.ee/analog/jx-10-m-16c.htm
>

This one?

http://www.batteryspace.com/nimh-rechargeable-cell-1-3-aa-1-2v-280mah-nimh-rechargeable-batteries.aspx

This one?

https://www.amazon.com/300-Mah-Nimh-Battery-Tabs/dp/B00JA0BIPW

Or a bunch here?

https://www.batterygiant.com/Primary-Cells/showcell.asp?cell=1/3%20AA

Prices may vary.


Peter Wieck
Melrose Park, PA

[pf...@aol.com]

I know they are not LiPo batteries, but if they are to be rechargeable, that should not matter. I am hunting another source for an actual LiPo device.

[Gareth Magennis]

wrote in message
news:304c6be3-e26b-4599...@googlegroups.com...

*****************************************************************


Hi Peter,

all those are rechargeable NiMH cells.

I need a battery that will keep it's charge over many years without
recharging.
This is a memory backup application, where charging of the backup battery is
not possible.



Cheers,


Gareth.

[Gareth Magennis]

wrote in message
news:e2963c78-4737-47ed...@googlegroups.com...

****************************************************************


Sorry, I'm replying to your posts in the wrong order!

So, how long would you think a 1/3AA NiMH would remain able to backup a
memory chip?
I suspect current draw is negligible, it is more down to shelf life
charged.


Cheers,


Gareth.

[pf...@aol.com]

>
> I need a battery that will keep it's charge over many years without
> recharging.
> This is a memory backup application, where charging of the backup battery is
> not possible.

OK. Is this the standard 3.7V of the typical LiPo style battery or something else? If it is that standard, how high can you go and how low can you go? I am thinking that you will need to cobble something with button cells to the correct voltage and use conventional watch cells. You could use LiPo watch cells and stack them - but in parallel, not series using little ladder devices (I could send you a sketch, having done it) and then shrink-wrap the results to make it one piece. LiPos self-discharge at about 2%/year, or at least the very good ones do, so several in parallel should do nicely for as much as 15 years before becoming 30% down (other than from actual use).

[pf...@aol.com]

Lithium Iron-suphide (Li-FeS2) has a 10-year service life in applications such as you describe.

Lithium Iron batteries (if you can even find them) go to 20 years, and are highly resistant to extreme ambient conditions.

I have not seen either of this in the configuration you need, nor have I really done any searching. But I have seen LiPo button cells - so that may be the most expedient approach.

[Gareth Magennis]

wrote in message
news:acc680b8-e90b-41ab...@googlegroups.com...

**************************************************************


Datasheet says 2v minimum, it is a 5 volt device.
Anywhere in between should be good.

http://www.datasheetcatalog.com/datasheets_pdf/H/M/6/2/HM6264LP-70.shtml



I'm willing to try the watch cell thing, but am a little nervous about
soldering directly to a Lithium battery.

I'm also thinking that in this particular application, you wouldn't
necessarily expect another 15 years out of it.
A good few years would probably cope with expectation here, we are talking
Vintage Synths.



Cheers,


Gareth.

[pf...@aol.com]

>
>
> Datasheet says 2v minimum, it is a 5 volt device.
> Anywhere in between should be good.
>
> http://www.datasheetcatalog.com/datasheets_pdf/H/M/6/2/HM6264LP-70.shtml
>
>
>
> I'm willing to try the watch cell thing, but am a little nervous about
> soldering directly to a Lithium battery.
>
> I'm also thinking that in this particular application, you wouldn't
> necessarily expect another 15 years out of it.
> A good few years would probably cope with expectation here, we are talking
> Vintage Synths.

Y'all don't need to solder. you will get two small pieces of brass or copper flat-stock, and some thin PTFE (Teflon) sheeting. Stack the batteries to the correct height for the use. Between each goes a small piece of Teflon as an insulator. Cut the flat-stock so little legs come out at battery-height for each battery. One goes *UP* for the one pole, the other goes *DOWN* for the other. Shrink-wrap the entire shebang. That makes positive contact for as many cells as needed in parallel, not series. Lace your fingers, put a piece of paper between each, the left hand fingers are on the bottom of the piece, the right hand fingers on the top as illustration. If you are a fanatic, you will use a drop of electronics-grade (no acetic acid) silicon to seal the top and bottom but for where the copper strip comes out for connecting to the board.

Been there, done that. The application was a bias cell for a vintage 1930s Coronado radio.

http://antiqueradios.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=29062&g2_serialNumber=2

That was 15 years ago, still going strong. I needed only 1.5V, but I wanted a bit more longevity than a single watch cell would provide.

[Gareth Magennis]

wrote in message
news:c155d687-4a1f-4290...@googlegroups.com...

*****************************************************************************************************

I haven't the room to do that.

I don't want to rely on physical contacts unless I have to, I would rather
solder.
That way I can guarantee a jolt would not erase the memory contents.



Cheers,

Gareth.

[Robert Roland]

On Fri, 10 Mar 2017 18:13:53 -0000, "Gareth Magennis"
<soundser...@outlook.com> wrote:

>I am having difficulty finding a 1/3AA Lithium battery.

They are called CR1/3N or CR11108. Search for that, and you'll find.
If you can find them with solder tabs, however, is another matter.

>It is for this application, any substitute has to fit in pretty much the
>same space as 1/3AA, there is no spare room.
>http://wolzow.mindworks.ee/analog/jx-10-m-16c.htm

It looks to me like this battery is used only for keeping the SRAM
data alive. If so, the current draw will be very low. If you can find
a smaller 3V cell, that will still work for a long time.

You could also stack two LR44 cells. The size should be about right.

>I did find rechargeable NiMH types, but I don't think they will keep their
>charge for the years expected of a memory backup battery?

Rechargeables are not the right tool for this job.

>Perhaps I could utilise watch type button cells, if I could find a holder
>for them.

That is a good idea. If you can find a combination of holder and
battery that will fit, that would be a good solution. You could look
for both dual 1.5V or single 3V solution.

Looking at the device, it does not look complicated at all. Are the
high prices because of the collectible value, or would people be
willing to pay similar money for a new, compatible device?
--
RoRo

[Gareth Magennis]

"Robert Roland" wrote in message
news:m4k7cc5eejjhhhvtv...@4ax.com...

**********************************************************


Ah, thanks for that, I was only searching 1/3AA.

Farnell have this, which I could make fit.
http://uk.farnell.com/varta/6131201501/battery-lithium-cr1-3n-170mah/dp/1781983


I think the original Roland cartridges would have some
collectible/sentimental value, but mostly people just want a working RAM
cartridge, as for some equipment this is the only way to get sounds in and
out of it.



Cheers,


Gareth.