Thanks for the clarification.
I have E-mailed Maxwell to inquire directly as to the
availability of a
hybrid/ultra-capacitor in their product line that can
overcome the ESR
barrier.
Will share if/when they reply.
BTW: This hybrid:
http://www.sonicelectronix.com/item_13509_Power+Acoustik+CAPCELL-300.html
claims "4.5 Milliohm int. resistance", based upon your
calculations that is 3.5MOhm
too high?
> Michael Keane K1MK wrote:
> On 6/19/2009 11:31 PM, kd4e wrote:
>> The specs on these claim "exceptionally low ESR".
>
> Number pleeez... ;-)
>
>> What is the ESR you would say is necessary for effective results?
>
> Rough Order of Magnitude you want 1/RC to be of order the frequency of
> the load variation that you're trying to smooth. So, for C = 1 F and f =
> 1kHz you want R < 1 milliOhm.
>
> Consider this device
> <http://www.maxwell.com/pdf/uc/datasheets/BC_15V_PAK_power_1009645_rev4.pdf>
>
> 20F and 32 mohm ==> 1/RC = 1.6 Hz that's not useful for load variation
> at audio frequencies.
>
>>>> I need to manage the load-spikes from a SSB modulated HF signal
>>>> through a solid state RF amp.
>>>>
>>>> Rather than two $190. 90lb batteries I can use one large battery and
>>>> one Hybrid cap and in my intermittent load application be in good
>>>> shape.
>>>>
>>>> Yes?
>>>
>>> No. The cap is of no benefit for the dynamic load application
>>>
>>> Because of its relatively high equivalent series resistance, an
>>> electrochemical capacitor cannot discharge quickly enough to help
>>> supply some of the current needed on voice peaks.
>>>
>>> Used in a car, an electrochemical cap is effective at keeping the
>>> headlamps from dimming because the filaments in the lamps respond
>>> slowly. But in that application, such a device doesn't prevent the
>>> car stereo (or radio) from seeing the same voltage fluctuations under
>>> modulation. That's why these super capacitors for car audio systems
>>> are all hype; it's the wrong application for this technology.
>>>
>>> 73,
>>> Mike K1MK
--
Thanks! & 73, doc, KD4E
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