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Re: [OM] Battery types [was - iPods from Apple]

Subject: Re: [OM] Battery types [was - iPods from Apple]
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Mon, 20 Dec 2010 07:37:23 -0500
Thanks.  I'm not sure what I was looking at before but 5 x 3.6 volts 
makes a lot more sense for an 18 volt pack.

Chuck Norcutt


On 12/20/2010 5:55 AM, Tim Hughes wrote:
> Chuck, ok I went and checked  the dewalt website this dewalt 18V pack
> has 10 smaller size A123 cells , so here they paralleled 5 pairs of
> cells to make the pack a little more compact:
> http://dewaltownersgroup.com/index.php?PHPSESSID=d886b14708b013d8bdc7af2fbf9af5f6&topic=168.0
>
>  this 12V dewalt is likely sony lifepo4 cells, but can't be sure, no
> label:
> http://dewaltownersgroup.com/index.php?PHPSESSID=d886b14708b013d8bdc7af2fbf9af5f6&topic=387.0
>
>  The rc model groups have reallly good information on
> dissecting/using the dewalt nano-packs for other purposes.Including
> 10min charging, abusive cycling etc.
>
> Tim Hughes
>
>
>
> --- On Mon, 12/20/10, Tim Hughes<timhughes@xxxxxxxx>  wrote:
>
>> From: Tim Hughes<timhughes@xxxxxxxx> Subject: Re: [OM] Battery
>> types [was - iPods from Apple] To: "Olympus Camera
>> Discussion"<olympus@xxxxxxxxxxxxxxxxx> Date: Monday, December 20,
>> 2010, 1:57 AM Chuck, I am not sure which of packs you are looking
>> at, as the dewalt line includes many types NiCd (old) ,NiMh,LiFePO4
>> (A123) and I believes some other technology Li-ion cells now too
>> (maybe Sony) in its cheaper Li line. The website is quite good
>> because it identifies cells used in quite a few vendors products.
>>
>> The VPX line from Black and decker use A123 nano-cells, but it is a
>> smaller size 1.1Ah cells.
>>
>> At the 18V pack level I believe you can use both the NiMH packs or
>> the LiFePO4 packs interchangeably in the 18V Dewalt tools and they
>> even have multifunction intelligent chargers that handle both
>> types.
>>
>> I seem to remember they have a lightweight Li pack and a heavy
>> weight pack at 18V one using 5x 2.3Ah cells and one using 5x 1.1Ah
>> cells. here are cell specs, download data sheet:
>> http://www.a123systems.com/a123/products  the 2.3Ah cell is model
>> 26650
>>
>> The Dewalt 36V 2.2Ah  packs are the most popular for dissection or
>> use in electric scooters etc. These contain 10 cells. Typically you
>> can get them new for ~$100 off ebay with patience. If you short the
>> cell while dissembling, you can literally vaporize the thick metal
>> tab. The actual voltage per cell averages more like ~3.3V . So an
>> 18V pack is actually about 16.5V in use, but due to the low
>> impedance is more constant under heavy load than say a NiMh.
>>
>> Just off charge the cells are about 3.55V or just under 18V for
>> pack. The common lithium ion etc batteries in laptops are just
>> under 4.2V coming off charge, but average a bit higher voltage than
>> LiFePO4,something like 3.5V or even 3.6 depending on particular
>> chemistry.  The energy density advantage of regular Li-cells, even
>> at low rates, soon fades as the cells automatically lose ~20% pa if
>> kept fully charged and lose even more when cycled. Cycle life is 5
>> to 10 times worse and self discharge is much higher for Li-Co
>> laptop type cells.
>>
>> Tim Hughes
>>
>>
>> --- On Sun, 12/19/10, Chuck Norcutt<chucknorcutt@xxxxxxxxxxxxxxxx>
>> wrote:
>>
>>> From: Chuck Norcutt<chucknorcutt@xxxxxxxxxxxxxxxx> Subject: Re:
>>> [OM] Battery types [was - iPods from
>> Apple]
>>> To: "Olympus Camera Discussion"<olympus@xxxxxxxxxxxxxxxxx> Date:
>>> Sunday, December 19, 2010, 6:24 AM Interesting.  But I was
>>> confused by the DeWalt link which appears to show a 12 volt
>>> battery with 3 cells and an 18 volt
>> battery
>>> with 6 cells. Aren't all of these rechargeable lithium
>> chemistries
>>> nominally 3.2 volts/cell?
>>>
>>> Chuck Norcutt
>>>
>>>
>>> On 12/19/2010 3:22 AM, Hughes wrote:
>>>> 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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