Since I have already done a few videos on mobile installs I thought I would throw this one in too. The MFJ-4403 Transceiver Voltage Conditioner! The MFJ-4403 Voltage ConditionerIs a pretty amazing item in that it not only protects your radio, but it will also allow you to plug into a cigarette lighter and run your radio at 100 watts SSB! The MFJ-4403 has six 4.16 Farad capacitors and blade fuses at the input and output. In this video I show that you can in fact use the MFJ-4403 Voltage Conditioner to make a contact using 100watts while plugged into a cigarette lighter.
I've been running my Icom IC-706 for years through a cigarette lighter plug with no problems since I replaced the 10 amp fuse in the fuse box with a 20 amp fuse. Used to blow the 10 amp fuses when the radio was up to full power.
Let's do some math here. The energy stored in a capacitor is 0.5 * C * V * V. So at 13.5V, these caps store roughly 1500 Joule which equals 1500 Ws. This sounds like a lot of energy and it is. However, suppose they charge up to 13.5V and under full load, the voltage at the cigarette lighter socket drops to 12V. In that situation, the caps only "bridge" the drop from 13.5V to 12V. That's 1.5V. The amount of energy used from the caps is then 18J or 18Ws. 18 Watt during one second. Or 100W during 0.18 second. That begs the question if that device does anything at all but drain your wallet.
TWENTY FIVE FARADS! Holy cow, thats a lot of short term energy storage in such a small box! Today few cars are equipped with actual cigar-lighters. Instead they have "accessory power outlets" and there is a slight but significant mechanical difference in the respective sockets, depth spec of plug center pole, etc. In theory this makes a cigar-lighter socket work with either a heating element or an accessory plug, but a cigar-lighting heater ought not activate if inadvertaently plugged into an accessory socket unless pushed in really hard which can be a safety issue as accessory sockets may not be designed to handle the heat load (plastic). The amp capacity of a modern socket varies too. My Mazda accessory socket is fused at only 10 amps. My old Thunderbird cigar-lighter socket was much more. But the problem plugging a 100w radio into either is not ampacity, but VOLTAGE DROP. At low load there was 12v at the socket. Receiving and QRP rigs can work just fine. But with more QRO, at instantaneous peak loads, > 10a / 100w input, this could drop to less than 10v. The wire guage, intermediate connectors, etc, for an accessory socket, are just too wimpy. This voltage drop can cause bizarre reactions in many rigs. Distorted audio, if not outright just shut off or power cycling. Serious damage could probably occur if prolonged. Plus that conducted high peak load power distortion can propagate throughout the vehicle to other devices and systems causing dimming lights or even other much worse weird problems, engine or brake electronics malfunctions. Large capacitance banks have been commonly applied for years in automotive high-end audio installations. Sometimes called "stiffening caps" they provide isolation and peak power capability for outboard power amps that supply bass woofer speakers, often remotely mounted under seats or in the trunk, which is a long wire run from the primary power source battery / alternator. Certainly its best to add a large gauge wire power feed directly from the battery post into the cabin or trunk for QRO radios / amps, but this is impractical for RENTALS. When flying and renting a car I like to take a small HF rig along with a triple-mag mount and a fist-full of Hamsticks or little Hustler whips. And with poor propagation today, the five watts of a FT-817 alone just doesn't hack it, bring the lite IC-7300. Expecially for enabling that to work better, this nicely packaged little MFJ unit seems like a good deal. 73, John, WØPV
This kind of crap gives ham radio operators a really bad name. This is exactly why pros consider hams CB operators. They have no clue what they are doing.
I wonder how this compares to something far cheaper, like this from Powerwerx: https://powerwerx.com/dc-line-noise-filter-powerpole-connectors The MFJ voltage conditioner can claim handling higher power, polarity protection, fuses, and a few other bits but I can buy 3 or 4 of those noise filters from Powerwerx for the same price. With Powerpole plugs there should not be any swapping of polarity. Assuming the car socket, the radio cord, or any other bits between the radio and battery have the correct fuses then the fuses and lights in the MFJ box adds nothing. If someone wants polarity checking then there's a cheap and quick fix for that too: https://powerwerx.com/testbuddy-powerpole-led-polarity-tester This looks like a relatively large and expensive box for what it does. If it had more Powerpole outputs, perhaps another switch to power up the outputs separately, a volt meter, breakers instead of fuses, and/or whatever, then it might be something I'd consider even if it cost a bit more.
The 20 amp fuse is great if the wire can take it without melting down. There may be some but I've never encountered a lighter plug that was fused higher than 10 amps. Do you suppose there's a reason for that?
I always wonder how much stuff MFJ sends out to these video makers? If their print ads is any indication I would guess a lot.
I own one and use it with my Yaesu 2m fm FT-2900 Or? FT-2980, I forget which I have mobile, LOL. For my previous vehicle it was badly needed, as the factory power outlet was rated 15 amps, and at high power I overloaded the fuse. Replaced the fuse with a 15 amp circuit breaker, and had it trip a couple times. Put the MFJ-4403 inline, no more problems. It does take a moment to charge the capacitors, so it is not instant On when starting the vehicle if it was off for more than just a few short minutes; such as a fuel stop. When I switched vehicles I transferred this into the current minivan. 73 K2HAT edited to spell fuse versus fuze, LOL...... duh more coffee...
Two different function devices. The Powerwerx appears to be a inline noise FILTER, while the MFJ is a parallel ENERGY STORAGE local supply.
I'm confused. Unless I'm in a friend's car or a rental, I would always run the power from the battery and not the cigarette / accessory outlet in my car. I MAY be able to understand this device if I'm going on a road trip in a borrowed vehicle...but not as a permanent install in my own ride. I've installed lots of car stereos and radios and never had too much trouble getting through the firewall. Shoot, didn't the Technician and above question pools say something about not using this socket for high power applications?
My 2016 Ram Promaster City; and 2018 Kia Sedona vehicles, I could not find a good place to route power thru the firewall, and was not going under the car and up through the floor LOL. I also do not drill a hole in the roof for a 2 meter antenna, a mag mount works okay. Yes it is all a compromise. I don't have an HF radio in the minivan, so this is my solution, and probably not needed in the Kia Sedona.
