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  1. #21
    Co-Pilot Antoni's Avatar
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    If you are saying you've got 18 Volts on your battery electrics you have a major problem and it does not involve the capacitor.

    If you can measure 18 volts with the engine running your regulator-rectifier is definitely up the junction.
    Last edited by Antoni; 20-09-18 at 00:48 AM.
    "The single biggest problem in communication is the illusion that it has taken place" - G.B.S.


  2. #22
    Co-Pilot oldbaldyman's Avatar
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    Or even one from China (ebay)63 volts 22000mf 1.99 works great!


  3. #23
    Wannabe Pilot Jinx's Avatar
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    This massive coke can (airplane size) capacitor is now fitted, it's quite different to the old capacitor that looked like a square of ravioli, still not sure of its value as it was in a lump of heat shrink.

    Most of the time my voltage sits around 14V but it does still peak at about 18 every now and then. Maybe it is time for a new regulator. I noticed this one ( https://www.carmo.nl/index.php?main_...oducts_id=2276) which doesn't require a massive capacitor. Wondered if anyone has tried it or has any recommendations to get the voltage down from 18v. Would probably need a mod to be submitted.

    I think the subtle buzzing has been attenuated too which is a bonus. Eventually it will be high end hi-fi quality on the intercom.


  4. #24
    Co-Pilot Arielarts's Avatar
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    It's a pretty evil waveform out of these regulators. The AC output voltage of the generator coils is allowed to build up to ~14.5v each half-cycle, then shorted out. A decent battery will smooth the resultant 'sawtooth' well, a large capacitor, less well. A cheap digital voltmeter may well respond to a spike of 18v, even though it's unlikely to have much energy. Best checked with a decent load connected - say a 12v 5W sidelight bulb.


  5. #25
    New Member GladBok's Avatar
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    Hi...i am a new user here. As per my knowledge actually 2.2mf is correct the esr wants to be lower than 10% ideally don't be a cheapskate go for low esr caps or forever suffer a high pitched whine, that's not me in year back seat its that cheap cap.


  6. #26
    Co-Pilot Antoni's Avatar
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    Welcome to the forum GladBok

    Like questions on this sort of subject.

    A near perfect 2.2mF capacitor (= 2200uF), ie one with low ESR and physically large enough to dissipate the heat generated within that ESR would be a better absorber of alternator whine than a good battery IMHO.

    But I don't understand your comment of ESR less than 10%. Do you mean not 10% more than the calculated reactance?


    [Edit: just noticed post 25 above contains a direct quote from post 4 of this thread]
    Last edited by Antoni; 20-09-18 at 00:49 AM.
    "The single biggest problem in communication is the illusion that it has taken place" - G.B.S.


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