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Battery holder for Duracell MN27 battery

06/14/2009 11:24 PM

Hi Everyone,

I am working on some small size op-amp and in-amp applications, but with ±10V outputs. Therefore I need ±12 to ±24 V input to my voltage regulators. I have been trying to find a battery holder for a Duracell MN27 battery. The battery is 12V, similar in SHAPE to an AAA battery. The dimensions are 0.3in/7.5mm OD x 1.07in/27.2mm Length.

I have searched the internet high and low to no avail. I'm suspecting that holders are built-in to custom cases and no standard holders are available.

If someone out there knows where I can find a case for this battery, whether 1-cell, 2-cell, or more, please let me know.

Mike

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#1

Re: Battery holder for Duracell MN27 battery

06/15/2009 10:44 AM

Try www.digikey.com or www.newark.com for these. One would think that battery holders were easier to find. I know the feeling!

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#2
In reply to #1

Re: Battery holder for Duracell MN27 battery

06/15/2009 4:43 PM

Hi NotUrOrdinaryJoe'

I should have said I've tried these places also (got desktop links to Digi-Key and Mouser) - no luck there.

Thanks for the reply though.

Mike

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#3

Re: Battery holder for Duracell MN27 battery

06/16/2009 4:02 AM

Tricky!

Can you change from an MN27 to an MN21 (a bit bigger).

Then use an N cell holder. An N cell is slightly larger than an MN21 but I think it should hold one okay; you'd need to check it out.

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#6
In reply to #3

Re: Battery holder for Duracell MN27 battery

06/16/2009 10:11 PM

Hi Randall,

Actually, due to a lack of foresight on my part, I have a number of the MN27s on hand already and want to make use of them before their shelf-life runs out.

I did look at the N-cell holder, and thanks for your input. It may be that I can use them via MNIce's suggestion.

Mike

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#4

Re: Battery holder for Duracell MN27 battery

06/16/2009 12:58 PM

I would suggest using some small invert and boost "point of use" switching supplies. Then common AAA batteries and the vast collection of holders could be used instead. An added advantage doing it this way would be that you could design the supply to regulate on a nearly exhausted battery at half voltage. The switching supplies will likely be much more efficient than a linear supply to also maximize battery drain. This approach will also allow you to increase circuit longevity by simply switching to C or D size battery packages without a circuit redesign.

One word of warning, be very conscious of phase margin with your op-amp circuits. Having just one loop drifting into oscillation will quickly drain your batteries.

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#7
In reply to #4

Re: Battery holder for Duracell MN27 battery

06/16/2009 10:22 PM

Hi redfred,

One of my goals was keeping the circuit & enclosure as small as possible, hence the higher-voltage small batteries. I already have a number of them on hand and want to use them before I'm too far into the shelf life. This is not a long term design - more for my own enjoyment than anything else.

Thanks for the input on op-amp design; I've been using Analog Devices devices(), using their ADIsim Design Tools:

http://designtools.analog.com/dtAPETWeb/dtAPETMain.aspx

I appreciate the input.

Mike

P.S. Like your signature statement!

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#9
In reply to #7

Re: Battery holder for Duracell MN27 battery

06/17/2009 9:57 AM

AD makes a lot of good analog devices. I particularly find their lack of "specmanship" refreshing. I fully understand the idea of using what you've got before it spoils. I do this often myself, and not just to keep the refrigerator from breeding.

You still might want to consider the switching supply regulators. This will permit using one battery instead of two, along with the other reasons I posted earlier.

Have Fun

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#5

Re: Battery holder for Duracell MN27 battery

06/16/2009 7:30 PM

If this is a one-of-a-kind project, you could use an N-battery holder by making a plastic cradle and metal spacer to adapt the MN27 to fit. The cradle could be a 12 mm plastic or wood dowel drilled to fit the battery and cut slightly shorter so it doesn't interfere with the contacts. A 3 mm x 12 mm steel disk to make up the difference in battery length, placed on the spring contact end, would do the rest.

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#8
In reply to #5

Re: Battery holder for Duracell MN27 battery

06/16/2009 10:27 PM

Hi MNIce,

Thanks so much for the input! I am not an ME and so hadn't got to making a "spacing" workaround. I have found N holders and, with your suggestion, I will proceed down that road.

If I could cast 2 votes, you would have a GA!

Mike

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Users who posted comments:

Mikerho (4); MNIce (1); NotUrOrdinaryJoe (1); Randall (1); redfred (2)

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