Why can't my electric stapler use Nicad batteries ?

Probably has to do with surge current.

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

Hi all,

I just got an inexpensive ($15) electric stapler from Staples and the manual says that it is ok to use alkaline batteries but not to use regular manganese or nickel cadmium ones. Anyone know why ? will it hurt the nicads if I do use them ?

Thanks

"Rodo" schreef in bericht news:x8z%e.2630$UD6.393@trnddc04...

manual

nicads

Not enough current and/or voltage. Nicads are 1.2 volt. It won't hurt but probably don't stitch either.

--
Thanks, Frank.
(remove \'q\' and \'.invalid\' when replying by email)

Nickel-based rechargables have a relatively high self-discharge rating.

Which is not what you want in something that sits doing nothing most of the time, such as remote-control handsets or staplers.

Alkaline cells will typically last a year in an IR handset, whereas NiCd/NiMH cells self-discharge way sooner.

Nickel cells are best suited for things that get through cells quickly, e.g. power drills, Walkmans, MP3 players, etc.

I read in sci.electronics.design that Clive Tobin wrote (in ) about 'Why can't my electric stapler use Nicad batteries ?', on Sat, 1 Oct

2005:

The other answer is that the low Ah capacity of cells, especially NiCds, other than hot alkalines has generated complaints about the product 'eating batteries'.

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Nicads don't like large loads on them. a stapler can produce large loads. and also they are lower in voltage and dont last as long .

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Not so. The can deliver very high currents. That's why they are used in drills and screwdrivers. Cheers, Roger

I wonder about a very cheap mechanism, that relies on the stall torque of the motor to not damage the mechanism. Torque will be higher with NiCd at high loads.

This may make sense. The stapler has a small motor to do the stapling.

Thanks .. to everyone.

i beg to differ, yes they are used in cordless screw drivers and such. and when it comes to high currents!, i have seen nicads blow their caps off from inrush of too many accurancies. the factor between nicads and Alkaline is that they can be recharged and that is the main reason whey they are used in such equipment. most devices that expect inrush currents are designed not to put the nicad cells into a state of super heating. the fact remains that Alkaline provides higher voltages and actually maintain a charge for longer periods. and yes, a stapler can get Alkalines hot also when used in successions. etc. P.S. i don't give much crecdence in Rechargeable Alkalines, i haven't found any yet that can maintain the life cycle like a non rechargeable type.

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Real Programmers Do things like this.
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"Jamie"

** On the contrary - they thrive on heavy loads.

......... Phil

"Rodo"

** The warning against Ni-Cds is most likely a safety issue.

An alkaline AA will deliver about 10 amps if shorted while a Ni-Cd AA can deliver up to 50 amps - enough to burn wiring and destroy small motors.

........ Phil

Can you post some urls that support your position? Ed

yes they are used in cordless screw drivers and such.

I suspect it is though...

There are several that will support this. Try:

or: Note particularly the comments uder the NiCd type. Historically, this is why NiCd batteries ar still favoured, in 'traction' type applications (together with lead acid). There are new generation NiMh batteries that are starting to move into this market (look at cordless drills, where some makes are now moving to NiMh), and these have comparable or even slightly better maximum currents. There ae two 'parts' to this, both the relatively low internal resistance (which is what matters in the mobile phone application), and also relatively good performance from the cell as it's temperature rises. This is why lead-acid, or NiCd batteries are being used in current electric car designs, and NiCd batteries for electric flight. NiMh, give higher total power capacities, but it their high capacity versions, have higher self-disharge rates.

As with all such things, there is a problem with 'generalisations'. High capacity batteries, usually have less actual electrolyte, thinner electrodes, and higher internal resistances. If one of these is substituted into an application designed for a battery supporting high currents, the result can very easily be cell rupture. Most manufacturers do both types in a specific chemistry. NiCd cells designd for traction use, are different 'beasties', from the sort commonly sold.

I suspect the real problem, is in cell voltage. The original poster, refers to the battery as 1.5v nominal, and then points out that a significant percentage of it's 'life', will be spent with a working voltage comparable to the NiCd cell. The 1.5v nominal voltage and discharge curve being talked about, sounds like that for a zinc-carbon battery, not the alkaline cell. For medium loads, this maintains a voltage over 1.25v much further into the design life, than for a zinc-carbon, or NiCd cell. I suspect the stapler, is one of an unfortunately 'common' class of devices, which only uses the first perhaps 40% to 50% of the cells capacity, and requires the higher voltage available here, which is not offered by the NiCd cell...

Best Wishes

Roger, I think you missed his point. He - the poster who said "I beg to differ" stated earlier: "Nicads don't like large loads on them. a stapler can produce large loads. and also they are lower in voltage and dont last as long . " He differs with the statement that nicds "can deliver very high currents. That's why they are used in drills and screwdrivers. "

Ed

Try:

OK. I was 'differing' with the wrong person. :-) However it is important to realise that a high capacity NiCd battery, not built for high loads, would then agree with the differer!. This is the big problem with such generalisations....

Best Wishes

in message

The design may depend on the internal resistance of the cell(s) being in a certain range. NiCds being lower in source impedance than alkalines might fry the innards.

Before you laugh, there are plenty of LED flashlights that use the battery resistance as the only series resistance outside of the LED itself.

Best regards, Spehro Pefhany

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You read the manual?

I have a suspicion that this might have something to do with it. I got a little digital camera the other day (well, some months ago) and it specifically states, in the Fine Manual, NOT to use Ni-Cads. Use only alkalines or NiMHs. NiMHs, it turns out, are pretty much a waste of time, but apparently the makers of the camera (Fuji) knew about the shortcomings of NiMHs - there's a menu selection, "Discharge", presumably so that when you need to recharge the NiMHs, you can put a totally empty cell in the charger. But it does admonish the user, "Do Not Use The Discharge Function On Alkaline Batteries!"...

But why not NiCds?

Ah! Found it!

"In the camera, use AA-size alkaline or nickel-metal hyydride batteres and the rechargeable battery NH-10. Do not use AA-size manganese or nickel-cadmium (Ni-Cd) batteries in your FinePix A205/A205S/A210 because the heat generated by the batteries could damage the camera or cause malfunctions."

So, they don't want their stapler to be blamed for a fire. :-)

Hope This Helps! Rich