Nimh battery type question

Archived from groups: rec.photo.digital (More info?)

John wrote:
> Why is it that some device manuals (such as my Gameboy Advance among others)
> indicate that I cannot use Nimh type batteries in my unit. Is this true, and
> will it ruin my gameboy, Walkman, Discman, GPS if I do indeed use Nimh type
> batteries in them?
>
> Thanks
>
>
> John

Hi...

"Regular" alkaline and old carbon-zinc batteries are
1.5 volts.

Nimh and nicd's are 1.2 volts.

However, trying them should't hurt the device.

Ken

Archived from groups: rec.photo.digital (More info?)

Bob Salomon <bob_salomon@mindspring.com> wrote:

> In article <ylmqd.360224$Pl.76361@pd7tw1no>,
> Ken Weitzel <kweitzel@shaw.ca> wrote:
>
> > However, trying them should't hurt the device.
>
> Bad advice. NiMh cells out gas and are ventilated. The products that use
> them also have to be vented. A classic example occurred a few years ago
> with a major brand of underwater flash equipment. Their flash units at
> that time were not properly ventilated for NiMh cells and several
> exploded while being used with NiMh cells.
>
> There are also other differences between NiMh and alkaline cells besides
> the nominal voltage. Things like the discharge curves and the current
> rating.
>
> I own an RCA remote for entertainment centers that uses four AAA cells.
> I get far longer operation on a set of alkaline cells then I do with
> NiMh cells with this system. Unfortunate as I would rather not continue
> buying the alkaline cells.

What about rechargeable alkalines?

--
Andy Hewitt ** FAF#1, (Ex-OSOS#5) - FJ1200 ABS
Honda Civic 16v: Windows free zone (Mac G5 Dual Processor)
http://www.thehewitts.plus.com

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"Bob Salomon" <bob_salomon@mindspring.com> wrote in message
news:bob_salomon-3B9107.11055428112004@news.isp.giganews.com...

> I own an RCA remote for entertainment centers that uses four AAA cells.
> I get far longer operation on a set of alkaline cells then I do with
> NiMh cells with this system.

You will do - NiMh's have a very high (relatively) self discharge. Leave
them fully charged for a few weeks doing nothing and they'll discharge all
on their own. Using them in low current drain devices like remote controls,
clock and so on is a waste as you get poor performance.

....

Archived from groups: rec.photo.digital (More info?)

Nice advice but that wasn't the question, plus they don't lose their charge
any where near as fast as poster's in this group would suggest.
Dave Cohen

"Harvey" <harvey@not.ntlworld.com> wrote in message
news:HOnqd.1289$Pi3.259@newsfe2-win.ntli.net...
>
> "Bob Salomon" <bob_salomon@mindspring.com> wrote in message
> news:bob_salomon-3B9107.11055428112004@news.isp.giganews.com...
>
>> I own an RCA remote for entertainment centers that uses four AAA cells.
>> I get far longer operation on a set of alkaline cells then I do with
>> NiMh cells with this system.
>
> You will do - NiMh's have a very high (relatively) self discharge. Leave
> them fully charged for a few weeks doing nothing and they'll discharge all
> on their own. Using them in low current drain devices like remote
> controls, clock and so on is a waste as you get poor performance.
>
> ...
>
>

Archived from groups: rec.photo.digital (More info?)

Batteries are cheap--abuse them! NiMH batteries self-discharge at about 1%
per day. Simply top off your batteries the night before you venture forth
with camera in hand and you will be happy. If you are not going to be using
the batteries for a while, forget about them. Store NiMH batteries at about
50% capacity then simply charge them up before use. I don't fully discharge
mine intentionally. They only need a couple or 3 good charge and discharge
cycles when new to "condition" them. They won't build up a "memory" effect
like NiCd batteries, but that only happens with NiCd batteries in rare
circumstances. NiCd batteries do like to be bottomed out before recharging
however, but you can still short charge them. As for NiMH batteries, slow
charging with a smart charger is much better and easier on them than a high
current fast charger. Either of the Maha chargers work well, and the more
expensive one that trickle charges and fast charges individual cells is the
best one.

Rudy, K8SWD
"Bill Tuthill" <can@spam.co> wrote in message news:41ab7f41@news.meer.net...
> Drifter <zespectre@askme.com> wrote:
>>
>> NiMH batteries start out with a lower nominal voltage (1.2v) than
>> alkaline batteries (1.5v) however there are a couple of additional
>> factors to consider.
>
> Actually NiMH batteries have a nominal voltage of 1.25 V and I have
> measured them close to 1.3 V when fresh.
>
> Somebody asked about rechargeable alkalines -- they provide about
> 1.5 V, and their self-discharge rate is negligible even over months.
> They last longer with shallow discharge/recharge cycles.
>
>> On the other hand are items like flashlights that will drain every
>> last erg of energy out of the cells (I.E. bottom them out). This is
>> very damaging to NiMH batteries and can cause the cells to fail early,
>> or even make them pop.
>
> I don't think this is true. In fact when new, NiMH cells should be
> conditioned by deep discharge. When older, they don't need this,
> as do NiCd cells. It is true that a full discharge counts more against
> total NiMH lifetime than a partial discharge. Whether or not it is
> proportional, I can't say.
>
> What you say in the above paragraph is true of rechargeable alkalines.
>

Archived from groups: rec.photo.digital (More info?)

"Bill" <bill@c.a> wrote
>
> Fully charged NiMH and NiCad battery cells should be 1.44v per cell.
> Nominal voltage is 1.20v per cell. Depleted cells should read 1.00v per
> cell. Going below 1.00v is not healthy and they should never be deep
> cycled (fully discharged).

There's absolutely nothing wrong with depleting a NiMH cell fully to 0v. It
will not damage it. People have that mistaken belief, because it *is* true
that you should never fully deplete a NiMH battery made up of more than 1
cell in series. Doing so risks that some of the cells will drain before
others and be "reverse charged". That will damage the weaker cells.

But if your device only uses 1 cell, you can leave it on for weeks and not
risk damaging the cell.

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"John" <crucifyself03@aol.comREMOVE> wrote in message
news:20041128084811.11907.00001045@mb-m16.aol.com...
> Why is it that some device manuals (such as my Gameboy Advance among
> others)
> indicate that I cannot use Nimh type batteries in my unit. Is this true,
> and
> will it ruin my gameboy, Walkman, Discman, GPS if I do indeed use Nimh
> type
> batteries in them?

Probably because of the slightly lower voltage.

NiCd and NiMH batteries are 1.25 volts under load; carbon-zinc alkaline
batteries, 1.5 volts. No damage will result from using an NiCd or NiMH
battery, but it will seem to be too weak and won't last long.

If they say NiCd is OK but NiMH isn't, that's a much harder problem, since
there is almost no electrical difference between them. The only device that
should suit one and not the other is a charger, because NiMH has higher
capacity and some NiCd chargers don't deliver enough power into them.

Archived from groups: rec.photo.digital (More info?)

"Ken Tough" <ken@objectech.co.uk> wrote
>>
>>But if your device only uses 1 cell, you can leave it on for weeks and not
>>risk damaging the cell.
>
> Yes, but how many digital cameras use only one AA cell?

Bill specifically referred to "cell", not "battery" or "multiple cells". I
do have flashlights that use a single cell, and therefore have no worries
about draining it completely.

If you use cells of the same brand, capacity, and purchase date, you're
probably pretty safe with letting them drain just about completely, even in
a flashlight. i.e., you could leave the flashlight on until it's producing
no light. Those cells will have very similar capacities, and all drain to
near 0v at the same time. (Besides, if one cell is significantly weaker, you
probably want to replace it anyway because it's defective. So who cares
about damaging an already defective cell?)