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[OM] Re: rechargable lithium ion batteries

Subject: [OM] Re: rechargable lithium ion batteries
From: Tim Hughes <timhughes@xxxxxxxx>
Date: Sun, 27 Apr 2008 03:51:08 -0700 (PDT)
They may be somewhat similar to these Chinese CR-V3 rechargeable batteries :
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1084
>From the vague specs for these, these might well be LiIon rather than LiFePO4. 
>They claim they
work well with the small flashes in the digital cameras, but who knows what 
that means in max
current terms.

Here is an actual vendor but specs are worthless:
http://www.globalsources.com/gsol/I/Camera-battery/p/sm/1006279291.htm
These vendors do seem to say though, "protection circuits built in" or similar.

The rechargeable versions of the smaller CR123A camera batteries, seem most 
often to be LiFePO4,
sometimes with added  electronics protection/voltage reduction. Those have 
current ratings of
under 1A.

Steve's Digcams lists a variety of retail sources for these CRV-3 some marked 
Digital camera
battery:
http://www.steves-digicams.com/nimh_batteries.html 
They point out the different chargers and cells are incompatible, which could 
mean different
chemistry depending on vendor.   A lot of these are rated at 1.3Ah-1.4Ah. If 
you assume they can
only do 1-2C max, a fairly typical rating for small cells, this means 1.4A to 
maybe 2.8A with
luck, but if they have active current limit then an alkaline might well do 
better.

Retail specs list voltage as: 3V for some of these cells,3.1V, 3.6V and 2.4V 
for the NiMH
versions. The NiMh will drop to 2.2V to extract reasonable capacity, so clearly 
these  digi
cameras are not too picky! 

Tim Hughes


--- John Hudson <OM4T@xxxxxxxxxxx> wrote:

> 
> The re-chargeable CR-V3s are labelled "Digital Rechargeable". There is no 
> manufacture's name specified nor a place of manufacture.
> 
> The warning label on the outer wrapping reads, in part  "........Keep the 
> battery in dry and cool environment. Keep battery out of children [sic] 
> reach."
> 
> Draw your own conclusions as to where these things originated.
> 
> jh
> 
> 
> 
> 
> ----- Original Message ----- 
> From: "Chuck Norcutt" <chucknorcutt@xxxxxxxxxxxxxxxx>
> To: <olympus@xxxxxxxxxx>
> Sent: Saturday, April 26, 2008 8:50 PM
> Subject: [OM] Re: rechargable lithium ion batteries
> 
> 
> > Probably all you have to do is check the specs for current draw on the
> > manufacturer's web page and compare to alkaline.
> >
> > Chuck Norcutt
> >
> > John Hudson wrote:
> >> I'd be quite willing to send Tim the batteries so that he could do the
> >> necessary diagnostics.
> >>
> >> Do I have a taker?
> >>
> >> jh
> >>
> >>
> >>
> >> ----- Original Message ----- 
> >> From: "Tim Hughes" <timhughes@xxxxxxxx>
> >> To: <olympus@xxxxxxxxxx>
> >> Sent: Saturday, April 26, 2008 7:10 PM
> >> Subject: [OM] Re: rechargable lithium ion batteries
> >>
> >>
> >>> Chuck,
> >>>      Actually most common Li ion batteries are not "rated" to give
> >>> particularly high current,
> >>> many are only rated 2C.  There are some types rated for higher currents
> >>> typically using a
> >>> different electrode material, but they are not so common except for
> >>> special uses radio control
> >>> helicopter users and power drills.  Most common Li-ion cells have built 
> >>> in
> >>> internal curent
> >>> limiting electronics, so you cannot draw too high a current, to prevent
> >>> them self igniting!   The
> >>> NiMH are actually frequently rated for higher current and more
> >>> importantly, don't have any built
> >>> in protection electronics.
> >>>
> >>> In this  particular case, of the so called  "3V " lithium batteries 
> >>> these
> >>> are frequently not
> >>> Li-ion, but some other Li chemistry like Li-FePO4 (~3.3) with 
> >>> electronics
> >>> or a diode to reduce the
> >>> voltage a bit more. They reqiuire a special lower voltage charger too. 
> >>> I
> >>> would not be surprised
> >>> if their rated current was quite modest, like <2A.
> >>> But this is a guess based on not seeing the batteries so, I can't say
> >>> definitively, except the
> >>> symptoms fit well with them having limited current capability.
> >>>
> >>> Tim Hughes
> >>>
> >>>
> >>> --- Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx> wrote:
> >>>
> >>>> But remember that these are supposedly rechargeable lithium ion
> >>>> batteries and not elemental lithium.  The thing that makes lithium ion
> >>>> batteries potentially dangerous is that they are capable of delivering
> >>>> far higher currents than alkaline or even NiMH batteries.
> >>>>
> >>>> So, I don't think your analysis can be correct if these are truly
> >>>> lithium  ion batteries.  But maybe the problem is that they're not
> >>>> lithium ion.
> >>>>
> >>>> Chuck Norcutt
> >>>>
> >>>>
> >>>> Tim Hughes wrote:
> >>>>> John,
> >>>>>      I am Making some big assumptions here, since I don't have enough
> >>>>> info from what you have
> >>>>> said, but I think this is what happens:
> >>>>>
> >>>>> When the flash capacitor is completely discharged at a cold start then
> >>>>> initially the current
> >>>> draw
> >>>>> is greatest. As the capacitor charges up a little the current is
> >>>>> somewhat reduced and then
> >>>>> eventually drops off rapidly near full charge.
> >>>>>
> >>>>> It may be the particular Li batteries you have, can't supply the very
> >>>>> high initial current of
> >>>> a
> >>>>> completely discharged flash capacitor and the internal electronics 
> >>>>> then
> >>>>> stops the charging,
> >>>> when
> >>>>> the battery voltage drops too much at cold start.  Once the capacitor
> >>>>> is slightly charged
> >>>> using
> >>>>> the regular batteries, then the Li batteries can supply the lower
> >>>>> current to continue charging
> >>>> it
> >>>>> up. The flash capacitor does not completely discharge even after a 
> >>>>> full
> >>>>> dump, so once you have
> >>>>> charged up the capacitor a little, with the regular batteries then it
> >>>>> will operate fine
> >>>>> thereafter, off the Li, until you switch it off and leave it to
> >>>>> discharge completely.
> >>>>>
> >>>>> Tim Hughes
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> --- om4t@xxxxxxxxxxx wrote:
> >>>>>
> >>>>>> I normally use two rechargable 3 volt lithium ion battery packs in an
> >>>>>> OM flash gun with my
> >>>> E510.
> >>>>>> The flash is a dedicated gun for the E series.
> >>>>>>
> >>>>>> When the flash has not been used for several days the battery packs 
> >>>>>> do
> >>>>>> not bring the flash
> >>>> gun
> >>>>>> to life. If I change over to four Ultra Duracell 1.5 volt batteries
> >>>>>> the gun springs to life.
> >>>> If
> >>>>>> I then change yet again to the LI battery packs the flash springs to
> >>>>>> life immediately. It is
> >>>>>> almost as if the flash needs to be initially energized with the
> >>>>>> Duracell batteries before the
> >>>> LI
> >>>>>> packs become operative.
> >>>>>>
> >>>>>> The LI packs are only a matter of a few weeks old, are fully charged
> >>>>>> and the connector points
> >>>> on
> >>>>>> both packs and in the camera are clean.
> >>>>>>
> >>>>>> When I start off from "cold" with the LI packs installed in the flash
> >>>>>> gun, the gun still
> >>>> remains
> >>>>>> inoperative even if I jiggle the packs slightly or apply a little
> >>>>>> pressure to the slide mount
> >>>>>> cover on the flash gun casing so as to effect a "better" contact
> >>>>>> between the terminals on the
> >>>>>> packs and in the camera.
> >>>>>>
> >>>>>> Does anyone have any idea about what might be ailing my flash gun and
> >>>>>> / or LI battery packs?
> >>>>>>
> >>>>>> John Hudson
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> ==============================================
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> >>>>>>
> >>>>>
> >>>>>
> >>>>>
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> >>>>>
> >>>>>
> >>>>>
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> >>>>
> >>>
> >>>
> >>>
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> >>>
> >>
> >>
> >> ==============================================
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> >>
> >>
> >>
> >
> > ==============================================
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> > ==============================================
> > 
> 
> 
> ==============================================
> List usage info:     http://www.zuikoholic.com
> List nannies:        olympusadmin@xxxxxxxxxx
> ==============================================
> 




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