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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