Logitech wireless keyboard and rechargeble batteries

[ATCSMike]

I just got a Logitech Cordless Mx Duo and the insert said not to use
rechargeble NiMH batteries in the keyboard. Anyone know why? Seems to me
they should work just fine. Anyone using rechargeble batteries in their
wireless keyboards?

Mike
--
AOL AIM: Jon Ne Reb
Yahoo Messenger: frostbitemike
United States Navy 1979-1982
Aviation Machinists Mate 2nd Class
VT-23, HS-1, USS Carl Vinson CVN70 (Plank Owner)

email treesqueak (at) gci (dot) net

 

[JAD]

yes - Logitech cordless optical duo.

 

[John Doe]

The short answer to your question is "don't worry about it, use the
rechargeables if you feel like it". The long answer is below.

I just got a Logitech Cordless Mx Duo and the insert said not to use
rechargeble NiMH batteries in the keyboard. Anyone know why?

Without looking, I think they would say rechargeable without
specifying NiMH.

Seems to me they should work just fine.

Yes, they should work just fine.

For what it's worth. The NiMH rechargeable might run longer than
alkalines, but not in very low current applications like my wireless
keyboard and probably yours. The problem is leakage current.
Alkalines last very long in very low current applications because
alkalines do not leak electricity like rechargeables do.

Anyone using rechargeble batteries in their wireless keyboards?

Currently I am using alkalines in my keyboard. I am using
rechargeable NiMH in my mouse, gamepad, and joystick. The keyboard
alkalines last for more than six months (probably, it's a very long
time). The mouse NiMH last for about one month (not really sure, but
I think it's short enough to justify using NiMH). If you put NiMH
rechargeables in your keyboard, they probably won't last long as
alkalines. But, if you think the rechargeables don't last long enough
in your keyboard, you can always try alkalines.

Have fun.




--
By the way. I would avoid Energizer's recharger. Their $30 model is
giving me fits. It charges AA batteries OK but it forces me to
reinsert AAA batteries over and over again until the stupid thing
will begin charging them. It is the ultimate in frustration. Next
time I am going to buy the Duracell charger. It will also charge
individual batteries (1 to 4). Good luck.

 

[ATCSMike]

The short answer to your question is "don't worry about it, use the
rechargeables if you feel like it". The long answer is below.




Without looking, I think they would say rechargeable without
specifying NiMH.




Yes, they should work just fine.

For what it's worth. The NiMH rechargeable might run longer than
alkalines, but not in very low current applications like my wireless
keyboard and probably yours. The problem is leakage current.
Alkalines last very long in very low current applications because
alkalines do not leak electricity like rechargeables do.




Currently I am using alkalines in my keyboard. I am using
rechargeable NiMH in my mouse, gamepad, and joystick. The keyboard
alkalines last for more than six months (probably, it's a very long
time). The mouse NiMH last for about one month (not really sure, but
I think it's short enough to justify using NiMH). If you put NiMH
rechargeables in your keyboard, they probably won't last long as
alkalines. But, if you think the rechargeables don't last long enough
in your keyboard, you can always try alkalines.

Have fun.

Thanks for the info. I didn't know about the battery leakage stuff. I'll
stick with regular batteries for the keyboard. I've been seeing Lithium
batteries (non-rechargeble) showing up in stores lately, I wonder how
they would do in the keyboard.

Mike

--
AOL AIM: Jon Ne Reb
Yahoo Messenger: frostbitemike
United States Navy 1979-1982
Aviation Machinists Mate 2nd Class
VT-23, HS-1, USS Carl Vinson CVN70 (Plank Owner)

email treesqueak (at) gci (dot) net

 

[dg]

Lithium batteries (non-rechargeable kind) are known for having the longest
shelf life of any kind of battery. Also known for having the highest cost
of any battery I have ever seen. I bet they would work well in a keyboard,
but not well enough to justify the cost.

--Dan

 

[nobody]

I just got a Logitech Cordless Mx Duo and the insert said not to use
rechargeble NiMH batteries in the keyboard. Anyone know why? Seems to me
they should work just fine. Anyone using rechargeble batteries in their
wireless keyboards?

Mike

Two possible problems:

1) The voltage of a standard alakline cell is 1.5V,
whereas NiMH give only 1.2V.

2) Alkalines are very good for low-current, long-duration uses,
as their high internal resistance virtually stops charge leakage.
NiMH, on the other hand, will self-discharge rapidly. I've see
figures for NiMH self-discharge rates of between 3% & 10% per
day.

 

[JAD]

well that would put these Ni's at a (negative) -8 volts by now.....KB
NI's are in for over a month now....still over 60% of the charge left.

 

[spodosaurus]

I just got a Logitech Cordless Mx Duo and the insert said not to use
rechargeble NiMH batteries in the keyboard. Anyone know why? Seems to me
they should work just fine. Anyone using rechargeble batteries in their
wireless keyboards?

Mike

I have the older version of the logitech wireless keyboard and wireless
optical mouse. The mouse chews through NiCd batteries like they were
candy. NiMH batteries work well in it (it = mouse). I now use my old
NiCd batteries in the keyboard. I don't know why there would be a
prohibition against using NiMH batteries in the keyboard unit, but I'm
sure one of the other contributors here will get an answer to you.

Cheers,

Ari

--
spammage trappage: replace fishies_ with yahoo

I'm going to die rather sooner than I'd like. I tried to protect my
neighbours from crime, and became the victim of it. To jump to the end
of the story, as a result of this I need a bone marrow transplant. Many
people around the world are waiting for a marrow transplant, too. Please
volunteer to be a marrow donor:
http://www.abmdr.org.au/
http://www.marrow.org/

 

[nobody]

...well that would put these Ni's at a (negative) -8 volts by now......

Wrong.

Self-discharge refers to reduction in a battery's real capacity,
rather than (specifically) its voltage.

Say your NiMH AA battery has a capacity of 1400mAH and it's fully
charged and topped-off.

Leave it on the shelf for 24 hours, and its capacity is now:

1400 - ((1400/100) * 3) = 1358mAH
(assuming a 3%/day self-discharge rate)

Leave it on the shelf another 24 hours, and its real capacity is:

1358 - ((1358/100) * 3) = 1317mAH

....etc etc.

...KB NI's are in for over a month now....still over 60% of the charge left.

How is the remaining charge being measured?

 

[John Doe]

My estimate for NiMH leakage current would be less, but still many
times higher than alkalines.

Even if not for high leakage current, why would you want to use
NiMH rechargeables in a very low current device?

If your NiMH rechargeables last for six months, you would be able to
recharge them roughly 120 times in 60 years. They are rated for 1000
recharges.

Are NiMH rechargeables safer for the environment than alkalines? I
know they are much less harmful than nickel cadmium rechargeables.

 

[JAD]

Freakin setup....so you can explode your prowess to the functions of
batteries.....WRONG! indeed...there in for more than a month- 3% to
10% a day would be ridiculous............ and its was an arbitrary
remark...the gist is....there in- they work -and don't die in a
week... of course if your constantly using a keystroke to zoom in and
out of porn pictures your battery life will suffer......allota nothing
bout nothing

<<How is the remaining charge being measured?

With a battery tester,,,no wait I put them on my tongue\\

cousin of _tom?

 

[JAD]

whats the header for?

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Subject: Re: Logitech wireless keyboard and rechargeble batteries
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My estimate for NiMH leakage current would be less, but still many
times higher than alkalines.

Even if not for high leakage current, why would you want to use
NiMH rechargeables in a very low current device?

If your NiMH rechargeables last for six months, you would be able to
recharge them roughly 120 times in 60 years. They are rated for 1000
recharges.

Are NiMH rechargeables safer for the environment than alkalines? I
know they are much less harmful than nickel cadmium rechargeables.

 

[John Doe]

Say your NiMH AA battery has a capacity of 1400mAH and it's fully
charged and topped-off.
Leave it on the shelf for 24 hours, and its capacity is now:
1400 - ((1400/100) * 3) = 1358mAH
(assuming a 3%/day self-discharge rate)
Leave it on the shelf another 24 hours, and its real capacity is:
1358 - ((1358/100) * 3) = 1317mAH

According to the graph I have, the capacity drop is much steeper at
first.

At 25°C the capacity drops to about 92% in 24 hours, then it becomes
roughly linear while dropping to about 82% in 10 days.

At 37°C the capacity drops to 80% in two days.

Have fun anyway.

 

[John Doe]

I thought we were all wild and free? [teasing].

 

[ATCSMike]

I have the older version of the logitech wireless keyboard and wireless
optical mouse. The mouse chews through NiCd batteries like they were
candy. NiMH batteries work well in it (it = mouse). I now use my old
NiCd batteries in the keyboard. I don't know why there would be a
prohibition against using NiMH batteries in the keyboard unit, but I'm
sure one of the other contributors here will get an answer to you.

Cheers,

Ari

I've decided to keep alkaline batteries in the Keyboard, maybe I'll
switch to Lithium when they die. My mouse uses NiMH, I thought they were
NiCd. I didn't even know NiMH existed. Du oh!

Mike
--
AOL AIM: Jon Ne Reb
Yahoo Messenger: frostbitemike
United States Navy 1979-1982
Aviation Machinists Mate 2nd Class
VT-23, HS-1, USS Carl Vinson CVN70 (Plank Owner)

email treesqueak (at) gci (dot) net

 

[spodosaurus]

I've decided to keep alkaline batteries in the Keyboard, maybe I'll
switch to Lithium when they die. My mouse uses NiMH, I thought they were
NiCd. I didn't even know NiMH existed. Du oh!

Mike

I have a nice Maha (Powerex) fast charger for my NiMH batteries that I
bought for my digital camera (I got it from www.thomasdistributing.com)
that I absolutely love for use with my mouse as the mouse gets a lot
more use than the camera.

Cheers,

Ari


--
spammage trappage: replace fishies_ with yahoo

I'm going to die rather sooner than I'd like. I tried to protect my
neighbours from crime, and became the victim of it. To jump to the end
of the story, as a result of this I need a bone marrow transplant. Many
people around the world are waiting for a marrow transplant, too. Please
volunteer to be a marrow donor:
http://www.abmdr.org.au/
http://www.marrow.org/

 

[nobody]

Freakin setup....so you can explode your prowess to the functions of
batteries.....WRONG! indeed...there in for more than a month- 3% to
10% a day would be ridiculous............ and its was an arbitrary
remark...the gist is....there in- they work -and don't die in a
week... of course if your constantly using a keystroke to zoom in and
out of porn pictures your battery life will suffer......allota nothing
bout nothing

No need to get all pissy.

I have no expertise in battery technology (witness my goof regarding
the big loss of charge during the first 24h), just been looking into
different battery techs with a view to building up a rechargable pack
for a bike light.

Look on the bright side: We both now know a little bit more than when
this thread started.

<<How is the remaining charge being measured?

With a battery tester,,,no wait I put them on my tongue\\

I'd treat the charge indicator on a consumer-grade battery charger
with a degree of scepticism - NiMH's have a very flat discharge curve,
so deriving the state of charge from their voltage is going to be
pretty inaccurate. The charger *could* be pushing some charge into the
batteries, and looking at dV/dt, and guesstimating from there, but I
doubt it.

Doesn't really matter anyway, since small NiMH's are so cheap these
days, who cares if you only get 300 charges out of them due to a
little mistreatment, rather than 500?