Nimh battery type question

What about rechargeable alkalines?

Worst of several worlds, from what I hear.

"Bob Salomon" wrote in message
...

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.

....

"Bob Salomon" wrote in message
...

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.

....

"Bob Salomon" wrote in message
...

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.

....

On 28 Nov 2004 13:48:11 GMT, EMOVE (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?

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.

#1 NiMH batteries (as someone else mentioned) do a bit of outgassing
when in use. This can have a corrosive effect on some electronics
that don't have the little "pellet" catalyst somewhere inside. For
something like a gameboy this probably isn't much of an issue as it's
not airtight.

#2) Discharge rate. This is probably the issue with the gameboy (and
with some other types of equipment). An alkaline battery has a
somewhat "self controlled" discharge rate when hooked to a short
circuit. They will certainly overheat and pop, but it takes longer.
NiMH batteries will "run wild" pretty quickly and can potentially burn
up an unregulated circuit in a matter of seconds.

#3 "Bottoming out". NiMH batteries are great for high-demand devices
that eat up batteries, but only when such devices shut down
automatically after the voltage drops below a certain level. Devices
of this type would be CD players, digital cameras, GPS devices, etc.
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.

There may be other issues that I either forgot to mention or don't
know about, but manufacturers usually put those warnings on for a
reason.


Drifter
"I've been here, I've been there..."

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" wrote in message
...

"Bob Salomon" wrote in message
...

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.

...

Drifter 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.

Drifter 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.

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" wrote in message ...
Drifter 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.

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" wrote in message ...
Drifter 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.