My 2018 Kia Sedona all the power outlets are fused at 20 amp from the factory. The USB power port at 15 amps! No alternator whine in this vehicle thankfully. https://fuse-box.info/kia/kia-sedona-2015-2018-fuses-and-relay
I have Hyundai Elantra GT I use for places my Tundra TRD wont fit well. One outlet is fused 20a the other 15a and is shared with the outlet in the rear hatchback where I went inside the opening and spliced in to feed power to my FTM-400. My Tundra has a 15a fused outlet in the console,this is were I tap power off for both the FTM-400 and my FT-891 in the truck. However I use an Li-Iron battery for the FT-891 for full power and use the truck to charge the battery when it is running only. I have an Epic power gate that also charges it from my solar panels I can deploy on the Tundra's Bed Cover. Ironic my 2018 USA built Toyota Tundra, I considered that buying a truck built by Americans.
Did you ever check the state of the supply wires after running your rig for years off that nominally 10A circuit? Might be interesting...
I hope that's an attempt at humor ? otherwise, it's a really BAD IDEA vehicle fires are no joke, except for your insurance company when they read your post .
Is an extra S unit worth the risk of torching your dashboard...? Run 30 watts and put more aluminum up.
Yes, voltage drop is a HUGE deal. I have a Kenwood ts450s that wont work at all below 12 volts. In the friendly user manual they make note of the wire size requirement for the DC power cord, and warn about voltage drop. All sorts of issues show up when the supply voltage drops below 12 volts; and the voltage available at the rig with too small of wire size will drop when the unit starts drawing enough current e=ir . This device with the large value caps sounds nice indeed. 73 Dave WA7AXT
My VW Golf has a 20A fuse feeding both sockets with a proviso in the manual of a 10A rating for each one. Big caps can indeed be dangerous (like misused batteries). Many years ago I worked in an electronics development lab where amongst other things we designed and built big float chargers an power supplies for alarm systems. Typically capable of 100A continuous at 48V I recall. One day the apprentice finished one and powered it up for a soak test before leaving for lunch. Yes you guessed it .. he wired the big electrolytic capacitors (8 of them) in reverse. A couple of minutes later there were several HUGE bangs and we had nice new holes in the false ceiling where the cans had punched right through. The air was filled with masses of pretty floating aluminium shreds. It took a week for the cleaners to get rid of it all.
This discussion might have been (_should_ have been) a lot shorter if the writers had seen a picture of the MFJ unit, or had read the catalog. It's not something you'd keep in your car all the time. Well, maybe if you're single, you might. To quote the catalog listing, it's for an "instant and foolproof portable/mobile emergency communications center". "Complete 'grab-and-go' communications center". It has a 3/8-24 mount for "such as a hamstick". And a built-in, full range automatic antenna tuner. It's definitely not "just a noise filter". It's made to hold a specific radio, too. It came out for the IC-706, models have come out for the IC-7000 and FT-897D (in the 2019 catalog). Just for those. AND it costs $430 (in the 2019 catalog) plus $21 or $30 for shipping. The AD5X review is available online as a PDF. Spoiler alert - he likes it!
A Li-Iron battery of a current rating that your radio will pull plus a charge controller for it will always be better than Super caps in a box at about + or - about 15% of the cost of that silly MFJ Box and "can be" about the same size...
Of course there is a reason. The reason is that the system is only designed for a maximum of 10A! Popping in a 20 amp fuse is asking for trouble. I have done a fair bit of commercial and industrial vehicle installations and have generally installed a 12 or 10 gauge wire from both the + and - battery terminals, even for 25 watt radio's. The 25F caps would likely reduce the instantanious current requirements for SSB, but not likely for CW or AM. I have seen too many instances where pushing the current limits of wire in vehicles have caused problems. Crimp connectors are notorious for causing fires, especially in older vehicles where the connections corrode and become a high resistance. Because of this, I always solder my crimp connections, and do not use crimp splices, EVER. Better safe than sorry. Clint, VE3CMQ
A properly crimped connector will never corrode because the contact surface between copper strands and the metal connector is airtight and fully metallic. Even the strands are deformed to hexagonal shape and no air exists between the strands. If done properly with enough force. There's plenty of literature to be found with microscopy pictures that show this. The problem is that most people who add/modify their cars' wiring are not willing to spend $300-$400 for a proper crimp tool. Instead, they use the cheap $10 rubbish from Home Deport or what have you. Soldering connections in cars is even against code. Vibrations and movenment of the wires make the solder joint brittle and it eventually breaks. Adding solder to a mediocre crimp-connection will however get you more mileage than without.
