Chuck,
The Newer LiFePO4 are truly outstanding, particularly the
"nano-technology" ones (A123), although the new Sony ones are a cheaper and
reasonable alternative now apearing, but not as high peak power. Dewalt
unfortunately charges a hefty premium for A123, but they are really worth it
for high power professional tools. You can get battery operated saws for
example, as powerful as line operated ones (1.5Hp). Black and Decker consumer
VPX series, also use A123 cells for small devices.
These have very Low self discaharge,very high peak power, not as high energy
density, but unlike normal Li-ion/poly they will maintain power for years of
abuse. I converted my Metz CT60 flashes to use them, and cut the weight to less
than that of smaller Oly CT45 for a more powerful 200J portable flash, with a
larger number of flashes too. Recharge in less than an hour.
If you are into tinkering the small VPX packs are easy to convert for use in
lots of different equipment and can be bought on ebay, at lower prices. I have
a number of old small screwdrivers,drills etc converted to use them. Just don't
drain them right down, keep a couple of packs and swap at first sign of
slacking and they will last and last. Some of the LiFePO4 packs now have
reasonable warrantys 2+years.
To see how powerful and relatively abuse proof the A123 cells are, go and read
the RC helicopter websites where they abuse these cells getting >250W from each
large c-cell and then recharging them in ~20minutes.
This website has lots of info on the cells used in different power tools mainly
dewalt, but includes others:
http://dewaltownersgroup.com/index.php?PHPSESSID=d886b14708b013d8bdc7af2fbf9af5f6&board=26.0
Lots of people buy LiFePO4 cell drill/saw packs for modifying, for all sorts of
high power applications off of ebay. This is often the cheapest way to get them
if you want to convert your old high power battery tools.
Tim Hughes
--- On Thu, 12/16/10, Bill Pearce <bs.pearce@xxxxxxx> wrote:
> From: Bill Pearce <bs.pearce@xxxxxxx>
> Subject: Re: [OM] Battery types [was - iPods from Apple]
> To: "'Olympus Camera Discussion'" <olympus@xxxxxxxxxxxxxxxxx>
> Date: Thursday, December 16, 2010, 2:02 PM
> I recently got a powered screwdriver,
> a Bosch. It says it has NiMH. It holds
> a charge for a really long time and lasts forever.
>
>
>
> From: Chuck Norcutt [mailto:chucknorcutt@xxxxxxxxxxxxxxxx]
>
> Sent: Thursday, December 16, 2010 1:57 PM
> To: Olympus Camera Discussion
> Subject: Re: [OM] Battery types [was - iPods from Apple]
>
>
>
> I think the perseverance of NiCd cells in certain
> applications is
> readily understandable in terms of the rate of self
> discharge. NiCd
> cells (until recently) have had much lower self discharge
> rates than
> NiMH cells. NiCD persists for a walkie-talkie or
> portable drill since
> you haven't been able to count on an NiMH powered device to
> have any
> charge left if you haven't used it in 3-6 months.
>
> But that all started to change recently. You may
> recall the
> announcement posted here the other day by Tim Hughes
> concerning three
> new types of NiMH batteries from Sanyo Eneloop. The
> newest cells
> promise 75% power after 3 years sitting on the shelf.
> That's probably
> better than NiCd, maybe even much better.
>
> Also, I note that drill drivers are starting to show up
> that have
> lithium-ion batteries. The last I noticed they were
> expensive enough
> that I wasn't willing to replace my own NiCD powered drill
> but the next
> power tool purchase could be something different.
>
> Chuck Norcutt
>
>
> On 12/16/2010 12:54 PM, Jan Steinman wrote:
> >> From: Moose<olymoose@xxxxxxxxx>
> >>
> >> On 12/15/2010 11:00 AM, Jan Steinman wrote:
> >>> Although it's open on my desktop, I've not
> looked at the
> >>> BatteryUniversity.com site yet, but my
> understanding of classic
> >>> NiCd is that repeated incomplete discharging
> to about the same
> >>> level causes a crystalline precipitate to form
> at a certain
> >>> location related to the discharge depth,
> therefore causing the
> >>> mis-named "memory effect." (It should really
> be called the
> >>> "forget effect." :-)
> >>>
> >>> Memory effect is not a problem when the cell
> is repeatedly
> >>> discharged to different levels. Classic case:
> a cop runs a
> >>> walkie-talkie for eight hours a day and drops
> it in the charger
> >>> overnight -- bad news for NiCd cell life. But
> memory effect is
> >>> not likely if you're using a flash or motor
> drive for various
> >>> periods of time and then topping off on a
> charger.
> >>
> >> "Among rechargeable batteries, nickel-cadmium
> remains a popular
> >> choice for two-way radios,"
> >>
> >> Since what you say here doesn't agree with what's
> on that site,
> >> perhaps you might read it and resolve the
> differences.
> >
> > Yea, I'll have to check that out, because it doesn't
> go along with my
> > experience as a ham-radio operator, my work as a
> repair tech in a
> > two-way communications shop, nor my stint as an RF
> engineer.
> >
> > I don't know of any hams who still use NiCd cells in
> their two-way
> > radios, but note that the OEM battery packs you get
> from Icom for
> > older radios still have them. Perhaps its just because
> NiCd's are
> > still cheaper. (New hand-held ham gear is almost all
> lithium
> > powered.)
> >
> > NiCds do have lower internal resistance than NiMH,
> which might make
> > them preferable in high-current applications -- like
> photo strobes.
> > But that wouldn't explain hand-held radios, which have
> relatively
> > moderate current needs. And if they're so good for
> hand-helds, why
> > don't you ever see them in cell phones? Puzzle.
> >
> > But such fun has to wait. I have to go pick up a buck
> to romance our
> > four Nubian goats today.
> >
> > Obligatory camera content: I need to take some photos
> of our
> > zero-mile raw goat milk ice cream... if there's any
> left...
> >
> > ---------------- Religions are the great fairy tales
> of conscience.
> > -- George Santayana :::: Jan Steinman, EcoReality
> Co-op ::::
> >
> --
> _________________________________________________________________
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>
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> --
> _________________________________________________________________
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>
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