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Old 08-01-2009, 08:25 PM
Hoppy Hoppy is offline
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Join Date: Sep 2008
Posts: 241
Quote:
Originally Posted by Harvey View Post
From where I sit, it seems we want a higher amplitude ring if possible. The frequency of that ring will depend on the battery and inductor combined resonance. Perhaps Hoppy or Milehigh can offer suggestions on methods of determining the battery capacitance so we can actually engineer a resonant circuit. My time is divided greatly over the next few days, but I will help where I can.

The Avalanche circuit inside the HEXFET serves to snub the ringing, but under certain conditions can actually exacerbate it when it encourages an increased current draw at the start of the spike but on the next cycles of the ring the Avalanche diode turns off for some reason. That would result in an increased field energy that dissipates in the ringing.

Rosemary, were any voltage measurements taken across the HEXFET? Did they ever exceed 1KV?

EDIT:
How can I measure the capacitance (NOT capacity) of a battery? - Yahoo! Answers
Chapter 9: Internal Battery Resistance
Although I have seen the fundamental resonant frequency of an LA battery quoted to be anywhere from 8.0KHz to 3.5MHz, the only resonance I can see possibly applying to this exercise is what is termed the 'absorbtion resonance' I have found this to be around 700Hz to 800Hz for an SLA battery. The absorbtion resonant frequency is the frequency where the battery can take maximum charge with least internal resistance at the commencement of the charging process. It is not IMO viable to see this circuit working in a classic resonant mode. Furthermore, as I've pointed out in an earlier post, given that batteries are non-linear systems, I can see no useful purpose using battery drain measurements by conventional load testing as an acceptable method of proving that this circuit is working overunity, unless the test circuit does in fact work at COP17 as claimed, in which case a straight 'before and after' battery capacity meter reading (BCM), although quite innacurate, will at least confirm that the system is working OU and should be more readily accepted by academics.

Hoppy
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Last edited by Hoppy; 08-01-2009 at 08:30 PM.