[ILUG] [Q] broken mouse work-arounds / replacements
watty at eircom.net
Fri May 29 09:28:26 IST 2009
Josh Glover wrote:
> 2009/5/28 Frank Peelo <f26p at eircom.net>:
>> Timothy Murphy wrote:
>>> On Thursday 28 May 2009 08:41:30 Josh Glover wrote:
>>>> 2009/5/26 Brian Foster <blf at utvinternet.ie>:
>>>>> I'm presuming the impact of rechargeable[s]
>>>>> is less than the impact of all the non-rechargeables.
Most studies are for NiCd. Which have about 1000 cycles, but about 1/2
to 1/3rd capacity of Alkaline.
Zinc Carbon can have 1/5th capacity of Alkaline and are same waste.
Alkaline work out much cheaper, so Zinc Carbon should be banned as wasteful.
NiMh can have similar capacity to Alkaline, but can self discharge in 2
weeks rather than 2 months of NiCd. They are also often only good for
about 300 charge cycles.
For clocks, Microphones, Memory backup and emergency torch the
Alkaline is best as storage can be up to 5 years and operation 1 to 2
years. NiCd no use as it goes flat, NiMH is even worse.
For Military or very high power the lower capacity NiCd is preferred
still due to much lower resistance (lower losses at very high power) and
much slower self discharge.
NiCd are very toxic to dispose of. NiMh is only slightly toxic.
Lithium batteries can even be landfilled as they are not toxic.
LiPoly are just a lower capacity physical structure to the 4 main
Lithium chemistries (one of which is not rechargeable.)
* The overall cost in money, carbon and environment is much lower
for NiMH and Lithium rechargeable than Alkaline.
* In suitable applications even Toxic NiCd and LeadAcid makes more sense
than disposable primary batteries.
Only 1/2 discharged Alkaline can be charged. Without a smart charger
there is risk of hydrogen vent and explosion. More than 1/3rd discharged
won't charge and any attempt is very likely to gas. It makes no sense
compared with NiMH.
Zinc Carbon should never be used.
Alkaline (or for 5 year micro amp Lithium primary) is best for very low
current / intermittent / emergency devices.
NiMH are to be preferred over NiCd on grounds of toxicity, though they
have higher self discharge. The 1/3rd as many charge cycles is offset by
Metal cased Lithium batteries are preferable for new designs, but need
special charging circuits.
LiPoly is only suitable for shorter life or very compact consumer
products as the lifetime is shorter and capacity is a bit less.
They are more easily pierced and prone to expansion.
Lead Acid (calcium) liquid, glass mat or Gel are still best for standby
(UPS) as NiMH or Lithium may fail or lose capacity on float charge, high
current (car starter, wheel chair etc). The Calcium technology means a
12V (6 cell) is nominally 14.2V rather than the traditional 13.8V, but
means the cell(s) stop passing current on charge and thus don't gas
hydrogen/oxygen using up the water.
>>>> I hope this is true, as I labour under the same presumption. :)
>>>> Has anyone pointers to research on this topic?
>>> [C]ommon sense seems to me to suggest you are wrong.
>>> Suppose a rechargeable battery can be re-charged 100 times
>>> and holds 1/2 the charge of a non-rechargeable.
>>> Then you would be saying that for some reason
>>> 50 non-rechargable batteries require less re-cycling
>>> than 1 rechargeable.
>> As I read it, they seem to be saying the opposite - that the environmental
>> impact of the rechargeable "is less than the impact of all the
> That's what I thought Brian was saying as well, and my editing (above)
> seems to support that fact. Once I removed all the supporting clauses
> and qualifiers, his sentence is quite clear.
> Common sense would dictate that recyclables have less of an
> environmental impact, but common sense is sometimes, er, a little too
> common. ;)
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