No, they are both low pass filters. Calling one a noise filter and the other an energy buffer is a distinction without a difference. I don't know what's inside the Powerwerx device but there are circuit diagrams available for the MFJ device. They put in a simple "pre-charge circuit" for the capacitors which may or may not be necessary to limit the inrush current to keep fuses from blowing. A similar effect could likely be achieved with an inductor, and that may be what the Powerwerx device does. Depending on the severity of the problem trying to be solved here, be it noise or voltage sag, will set just how complex the low pass filter needs to be. I'm quite certain that a half dozen little capacitors are insufficient to prevent voltage sag on a transceiver putting out more than a dozen watts for even a few seconds. After the capacitors lose what little extra power they can provide for those seconds then the voltage drops and they become a low pass filter. It may be a very nice low pass filter capable of filtering out considerable noise from the engine but it's really just a low pass filter at that point. To be any meaningful kind of energy storage will take something far larger than those capacitors in the MFJ voltage conditioner.
Absolutely, and this is what is so scary and disturbing, a trained licensed operator should know why. There are a few factors that determine how much current and voltage a conductor can withstand. The 4 most important factors are: Wire material (copper, aluminum, silver), insulation type and thickness of material, environment, and how many conductors are involved. It all boils down to heat. Each industry has their own electrical codes. Examples are building power and lighting (NEC), Marine, (ABYC), Automotive (SAE). Of those 3, the strictness in order is ABYC, NEC, and last SAE. In NEC codes a very common wire is 12 AWG. How much current can a 12 AWG handle? Well in NEC ranges from 8 to 40 amps. If a 12 AWG conductor has a 90 degree insulation inside a conduit with 40 or more conductors is limited to just 8 amps. Same conductor, a single in free air can handle 40 amps. Unlike NEC and ABYC where life safetyis priority 1, life safety is not #1 priority, weight and space are top priority. Automotive uses a high temperature insulation (105 degrees) as thin as possible (low voltage of 300 volts), and push as much current as the wire can handle. For most circuits in automotive only use one wire circuits (positive). Bottom line here is SAE or Automotive, pushes the thermal limits to the extreme, and replacing a 10-amp fuse with a 20 amp fuse in a automobile is something a CBer or ham radio operator would do. No professional or anyone who cares about life safety would ever do that. Only a fool would do that.
The MFJ-4403 manual diagram (page 6) is a bit confusing but the OP video clears it up nicely at 1:41. Its stated these six capacitors are 4.16 Farad, thats with a capital F, each, for nearly 25 FARAD total. To put in another persepective that's 25 MILLION microfarads (mF). Physical size aside, I would hardly call that "little" electronically. PLENTY of charge holding capacity to eliminate even serious peak voltage sags. More per watt then is even used for audio woofer amps. It's like a small short-term UPS with large caps instead of a small battery. There doesn't appear to be any low-pass filtering included in the MFJ, but it may inherently perform some anyway. The manual says it takes a FULL MINUTE after turning switch off for the bleeder resistor to fully drain the cap bank. I wonder if the 12vdc input is interrupted (without turning the 4403 off) just how long a small load like the FT-891 receiver (no xmit) would stay alive. Perhaps the OP @WJ6F could comment on that further.
If that's a 25 farad capacitor bank then I'm the queen of England. I've seen 4 farad capacitors before on hi-fi car audio installations and they were the size of a quart oil can. Taking a minute to discharge from the bleeder resistor means nothing, that's just saying it's not taking a large load. How big are those resistors by the way? Perhaps one whole watt? There's no heat sinks on those things and if it takes only a minute to discharge with those tiny things then just how much energy can those capacitors hold? I'd say a maximum of 6 watt-minutes. If the radio is pulling 120 watts then how many seconds will that last? I'll give my usual disclaimer again. I've been a code monkey for many years since I studied electrical engineering at university so it's quite possible I'm mistaken on a great many things. Even so I can do a little arithmetic using Ohm's law and recognize some basic electronic components. I'm thinking someone dropped a few orders of magnitude on the size of those capacitors somewhere.
Correction - staring at the schematic harder I see now they are six 25 Farad lower voltage caps in SERIES making the total for the bank 4.16 F. That is still a very impressive energy storage tank. Plenty for this application. Lower voltage super-caps are SMALL can be easily found by googling around like this example. And the OP vid pic of the insides clearly shows a big honkin' stone 15w resistor, probably the bleeder.
Your Majesty I present for your inspection a manufacture data sheet for Ultra Capacitors ranging in size from 1 to 3000 F. Quite small Form Factor for a capacitor, but like all capacitors have piss poor energy density. However your skepticism is well founded. To power a 12 volt toy from a super cap is no small affair and would require a Power Converter. You would need a capacitor to charge up to at least 100 volts or more. All one has to do is look at the discharge curves of any capacitor to understand why. If you were to only charge a capacitor to say 14 volts like an vehicle, none of the energy below 11-volts is not available to you. It forces you to leave roughly 80% of the energy inside without a noisy Buck Converter.
So when I do the math again, using 4.16F, this thingamabob would power your rig for a whopping 45 milliseconds during 100W peaks!
This thread makes me laugh. It is snake-oil looking for pigeons to pluck with very bad science. Super and Ultra Capacitors certainly have their applications, but this is not one of them. It is such a misuse of a technology, makes me wonder who the fools are? The one making them, or the ones buying them. Once you set the objectives, examine the options, cost, and complexity, Super Caps get eliminated very early as there are much better alternatives. Example, lets say we want to use a Power Port in a modern vehicle to provide 12 volt power to a small Transceiver like a VHF/UHF that requires 100 watt input. From a safety POV nothing needs to be done except fit the radio power cable fitted with the Port Connector. Consult Owners Manual but most Power Ports are limited to 150 watt maximum load which is a bit over-stated because the fuse will be 10-amps. So a 100-watt design limit is reasonable safety margin while getting the most power you can safely draw from the circuit. However from a Power Quality POV using the Power Port is unacceptable. The voltage loss, and common mode noise levels are just not acceptable. Well a Super Cap can resolve the noise issue, but cannot do squat about voltage loss unless you use a Noisy Power Converter. Doh!. Not only very expensive and complex, does not meet the objective. A better option and extremely effective is a Battery Pack. Same concept RV's, Telecom, Engineering, LMR, Competition A/V using a house battery, just on a much smaller scale. Use the vehicle alternator to keep the battery charged and supply power when running. Any power interface requires some precautions be taken. In this application a method to limit charge current, prevent house or auxiliary battery from back feeding, and a fuse between battery and radio. Two battery types come quickly to mind because they use the exact same voltages your vehicle uses. Either a small sealed AGM @ 20 AH range, or 4S LFP @ 10 AH. You could go as small a 4S LFP @ 5 AH. Eliminates voltage loss and noise using isolation from current limiter. Battery voltage will be roughly 14 volts at rest, and full load only dropping slightly outperforming a direct connection to the vehicle SLI battery in permanent installations. Can even work for a few hours with the Power Port turned off by the ignition. Not only would meet the objective, you blew them away for less cost. A few ways to get it done, but Super Caps is not one of them.
Not applicable - a stiffening capacitor only needs to dynamically compensate for the inductance and resistance of the leads to the lead-acid car battery. It NEVER should be expected to supply 100% (100w) of the power. Instead only the fraction needed to make up for instantaeous upstream power feed loss. An autotranformer in voltage boost configuration on an AC feed, far lower power rated then the actual load, is a loose analogy. Of course nothing is for free. The operating mode is important. It only enhances to a higher point SSB with its complex waveform, 10-20% average vs PEP. CW Morse code is derated (based on QRQ WPM? ) No benefit for RTTY, SSTV, nor even FT8
I disagree with you. Every transceiver has a few large capacitors directly connected to the power socket/leads. This is imperative for proper operation. So at the power leads you will never see a high frequency transient/peak in current draw. So any inductance of the power leads plays no role at all. Mind you: my FT-897 and IC-9700 each came with a 3m power lead, much longer than you will ever find in a car between the battery and the cigarette lighter. So the only thing this device and its capacitors will do is compensate a tiny little bit for the resistance of the fairly thin wires you find in a car. It forms an RC network with a small R and a large C. The only thing that happens if the transceiver needs 100W for a brief period of time, and the voltage drops from, say 13.5V to 12V across the internal car wiring is delay that drop for 45 milliseconds, based on the drop of 1.5V from a 4F capacitor. Anyone can do that math. And in my opinion, 45ms is way to short to have any positive effect on the peak output power of the transceiver, as the envelope of the peaks in a voice last much longer than that 45 ms.
Although I don't like the cigarette lighter/powerport connection for high current applications because of contact resistance, would be nice to see a real BEFORE and AFTER comparison with a volt meter at the radio power input and a watt meter at the radio antenna output. Show the benefit or lack there of using this device.
Utter engineering and marketing cobblers. More MFJ overpriced rubbish The only reliable solution is a direct feed off A battery. As someone else also alluded to, modern cars [anything in the last 20 years] REALLY do not like low battery voltage levels : all sorts of malfunctions and weirdness can occur if it drops just a little. And if you do feed it off the primary battery, make sure the engine is running. People who know what they are doing in Australia run separate batteries for accessories so they also don't run the chance of killing their starter battery and this dying in the middle of nowhere.
This is a second life for capacitors that were sold to make cars faster by "insert some weird jibberish about the fuel injection" that actually did absolutely nothing As has been pointed out, cars to run really small wiring for the load. I am always amazed at how hard the wiring is pushed when I work on a car. The lighter outlet is a really bad place to tap radio power if you have ANY other way to do it.
