Electrical Experts - Question re. Capacitor installation
LL - NY
larrycleung at gmail.com
Wed Oct 31 08:54:05 PDT 2007
No, a power lead with a cap MUST be in parallel. And the Cap should be
capable of filling in voltage drops IF it's of sufficient capacitance. In
reality, in order to properly size the cap, you really should O-scope the
ignition/injector power source current/voltage (scopes really only read
voltage) to find what frequency the drops/spikes are acting at. I don't
recall the equation needed (it's a diffy Q) to size the cap, but someone
here who does this more often can possibly help.
LL - NY
On 10/31/07, Ben Swann <benswann at verizon.net> wrote:
> Well I definitely don't want this acting like a choke – this is not
> points or hall-effect trigger. I would be using this as a stiffening
> capacitor, partially to compensate for inadequate wiring – even if the
> wiring is truly sufficient. I merely want to assure more than adequate
> power delivery to the coil even when there are power lags elsewhere,
> especially when running at very high RPM, eg. 8000+. The circuit should
> also have adequate reserve to pop the injectors open too.
> Of course I'll have one supplying the power amp in the rear of the car
> too. I saw a diagram that showed a cap in series to a power amp – I think
> it was a 4 farad. That did not make sense that the cap was wired with no
> other + feed. Would that be a correct hookup to an amp? Does having it in
> parallel have a detrimental effect, or is the series wiring not necessarily
> a good idea?
> Just trying to gain a more practical understanding of using power supply
> *From:* LL - NY [mailto:larrycleung at gmail.com]
> *Sent:* Wednesday, October 31, 2007 10:19 AM
> *To:* Ben Swann
> *Cc:* quattro at audifans.com; URQ
> *Subject:* Re: Electrical Experts - Question re. Capacitor installation
> A cap installed in a series in a DC circuit will not pass
> current until the circuit is actually shut down. It MUST
> be wired in parallel to be used as a part of a filter system
> for a DC power source. Choke Coils, OTOH should be
> installed in-line (series).
> The idea for both devices is to make the DC that goes
> to the head unit (or amp) *more* DC like, as they act as
> dampers to voltage (and by I = V/R) and current fluctuations.
> That being said, when we broke down one of our Magnetizers
> at work, I took a HUGE (as in 1.2 Farad) cap from the machine
> to use as a filter on my 4KQ's rear amp. It was meant for
> huge currents (around 200 Amps) at voltages well above
> automotive use (120V). Net filtering effect. Virtually nothing.
> LL - NY
> On 10/31/07, *Ben Swann* <benswann at verizon.net> wrote:
> I found this article to be helpful and shows the concept I was referring
> It looks like installing in parallel is OK, just need to be careful about
> charging and discharging.
> From: Ben Swann [mailto:benswann at verizon.net]
> Sent: Wednesday, October 31, 2007 8:24 AM
> To: quattro at audifans.com; 'URQ'
> Cc: 'Ben Swann'
> Subject: Electrical Experts - Question re. Capacitor installation
> Something new to my realm of expertise.
> I would like to install an electrolytic capacitor to act as a buffer for
> an ignition
> system - sort of like placing a second battery up close to the
> load.. Since the
> distance of the battery to the coil is about 7-8' and my understanding
> that a circuit
> may lag, it seems installing a large capacitor might be a good idea. If
> so, it makes
> sense that I'd install it in parallel with respect to feed wire and
> ground, however
> diagrams for most stereo AMP installations show the cap to be inline, with
> no other
> current path to the amp.
> Is it OK to install an electrolytic cap. as sort of a buffer or quick
> batteryin parallel with the circuit? That is basically to connect the
> positive end to
> battery post near load and ground as normal, leaving the original positive
> feed path
> intact. I have some 1 and 2 Farad caps and this is mainly to prevent lag
> at high RPM,
> similar to stereo clipping at high volume.
> Good Idea or ??? I'm doing some searches, but not finding a solid answer.
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